This document presents a new preon model with three fundamental spin-1/2 preons (α, β, δ) that can combine to form nine leptons, nine quarks, and nine heavy vector bosons. The preons have charges of +e/3, -2e/3, and +e/3. Quarks and leptons are composed of combinations of one spin-1/2 preon and one spin-0 "dipreon" made of two spin-1/2 preons. This model aims to address shortcomings of the standard model such as the large number of fundamental particles and mixings between particles, through a more fundamental layer of preons with an underlying symmetry.
A study of_the_dark_core_in_a520_with_hubble_space_telescope_the_mystery_deepensSérgio Sacani
This document summarizes a study using Hubble Space Telescope images to further examine the dark core detected in the galaxy cluster A520 in a previous study using ground-based data. The HST data provides over 3 times as many galaxies that can be used for weak lensing analysis, significantly enhancing the mass reconstruction. The analysis confirms the detection of the dark core coincident with the X-ray peak but lacking luminous galaxies at over 10 sigma significance. Several substructures are also clearly detected, including a new one labeled P5. However, the comparison of dark matter, hot gas, and galaxy distributions remains peculiar compared to other merging clusters.
The document studies small excitonic complexes in a disk-shaped quantum dot using the Bethe-Goldstone equation. It examines systems with up to 12 electron-hole pairs. For symmetric configurations where the number of electrons equals the number of holes, it finds:
1) The triexciton and four-exciton system show weak binding or possible unbinding in the weak confinement regime.
2) Higher complexes beyond four pairs exhibit binding in the weak confinement regime.
3) The Bethe-Goldstone approach provides better energies than the BCS variational method in the weak confinement regime.
This document provides a list and overview of various subatomic and composite particles categorized by type, including:
- Elementary particles like fermions (quarks and leptons) and bosons that mediate forces
- Hypothetical particles predicted by theories like supersymmetry
- Composite particles like hadrons (baryons like protons/neutrons and mesons) and atomic/molecular structures
It describes key properties and classifications of the different particles, such as their constituents, charges, and roles in the standard model of particle physics.
A multiband study_of_hercules_a_ii_multifrequency_vlaSérgio Sacani
This document summarizes a multi-frequency study of the radio galaxy Hercules A using the VLA radio telescope. The observations revealed that the bright jets and prominent rings have a flatter spectrum than the surrounding lobes and bridge, suggesting they represent a recent outburst from the active nucleus. The magnetic field closely follows the edges of the lobes, jets, and rings. There is also an asymmetry in the spectral properties between the two lobes that can be explained by relativistic beaming and light travel delays.
On Characterizations of NANO RGB-Closed Sets in NANO Topological SpacesIJMER
This document discusses nano rgb-closed sets in nano topological spaces. It begins by introducing the concept of nano topological spaces and various nano generalized closed sets. It then defines nano rgb-closed sets as sets whose nano b-closure is contained in any nano regular open set containing the set. Several properties of nano rgb-closed sets are established, including that every nano b-closed set is nano rgb-closed. Characterizations with nano rgb-closed sets and other nano generalized closed sets are provided, along with counterexamples showing the reverse implications do not hold. Continuity notions associated with nano rgb-closed sets are also introduced.
This document discusses research being done by Robert Ehrlich on the possibility that neutrinos may be tachyons, or hypothetical particles that can travel faster than light. Ehrlich believes that neutrinos, specifically the electron neutrino, may have a mass that would be consistent with it being a tachyon. He summarizes 6 observations from particle physics, cosmology and cosmic ray data that are all consistent with the electron neutrino having the mass of a tachyon. Definitive proof could come from the Katrin experiment measuring tritium beta decay or from observing fine structure in supernova neutrino signals.
The document discusses probing CP violation in supersymmetric stop decays at the LHC. It proposes using triple product asymmetries, which are CP-odd observables, to measure CP-violating phases like φAt and φμ. These asymmetries could allow detection of CP violation in stop decays via spin correlations with the second lightest neutralino at the LHC, providing an alternative to constraints from electric dipole moments. Large asymmetries and sensitivity to the CP phases are possible, and a detailed experimental analysis is motivated.
This document discusses principles of relative and absolute dating of geologic events.
[1] Relative dating involves determining the sequence of events without knowing exact ages, by applying principles like superposition, cross-cutting relationships, and inclusion. Absolute dating determines exact ages in years using radiometric dating techniques that rely on radioactive decay of isotopes like carbon-14 and uranium-238.
[2] Five diagrams are presented and labeled for practice determining the sequence of rock layers, faults, and unconformities using relative dating principles. Radiometric dating equations are also shown relating radioactive parents and stable daughter isotopes to calculate the time since a rock formed.
A study of_the_dark_core_in_a520_with_hubble_space_telescope_the_mystery_deepensSérgio Sacani
This document summarizes a study using Hubble Space Telescope images to further examine the dark core detected in the galaxy cluster A520 in a previous study using ground-based data. The HST data provides over 3 times as many galaxies that can be used for weak lensing analysis, significantly enhancing the mass reconstruction. The analysis confirms the detection of the dark core coincident with the X-ray peak but lacking luminous galaxies at over 10 sigma significance. Several substructures are also clearly detected, including a new one labeled P5. However, the comparison of dark matter, hot gas, and galaxy distributions remains peculiar compared to other merging clusters.
The document studies small excitonic complexes in a disk-shaped quantum dot using the Bethe-Goldstone equation. It examines systems with up to 12 electron-hole pairs. For symmetric configurations where the number of electrons equals the number of holes, it finds:
1) The triexciton and four-exciton system show weak binding or possible unbinding in the weak confinement regime.
2) Higher complexes beyond four pairs exhibit binding in the weak confinement regime.
3) The Bethe-Goldstone approach provides better energies than the BCS variational method in the weak confinement regime.
This document provides a list and overview of various subatomic and composite particles categorized by type, including:
- Elementary particles like fermions (quarks and leptons) and bosons that mediate forces
- Hypothetical particles predicted by theories like supersymmetry
- Composite particles like hadrons (baryons like protons/neutrons and mesons) and atomic/molecular structures
It describes key properties and classifications of the different particles, such as their constituents, charges, and roles in the standard model of particle physics.
A multiband study_of_hercules_a_ii_multifrequency_vlaSérgio Sacani
This document summarizes a multi-frequency study of the radio galaxy Hercules A using the VLA radio telescope. The observations revealed that the bright jets and prominent rings have a flatter spectrum than the surrounding lobes and bridge, suggesting they represent a recent outburst from the active nucleus. The magnetic field closely follows the edges of the lobes, jets, and rings. There is also an asymmetry in the spectral properties between the two lobes that can be explained by relativistic beaming and light travel delays.
On Characterizations of NANO RGB-Closed Sets in NANO Topological SpacesIJMER
This document discusses nano rgb-closed sets in nano topological spaces. It begins by introducing the concept of nano topological spaces and various nano generalized closed sets. It then defines nano rgb-closed sets as sets whose nano b-closure is contained in any nano regular open set containing the set. Several properties of nano rgb-closed sets are established, including that every nano b-closed set is nano rgb-closed. Characterizations with nano rgb-closed sets and other nano generalized closed sets are provided, along with counterexamples showing the reverse implications do not hold. Continuity notions associated with nano rgb-closed sets are also introduced.
This document discusses research being done by Robert Ehrlich on the possibility that neutrinos may be tachyons, or hypothetical particles that can travel faster than light. Ehrlich believes that neutrinos, specifically the electron neutrino, may have a mass that would be consistent with it being a tachyon. He summarizes 6 observations from particle physics, cosmology and cosmic ray data that are all consistent with the electron neutrino having the mass of a tachyon. Definitive proof could come from the Katrin experiment measuring tritium beta decay or from observing fine structure in supernova neutrino signals.
The document discusses probing CP violation in supersymmetric stop decays at the LHC. It proposes using triple product asymmetries, which are CP-odd observables, to measure CP-violating phases like φAt and φμ. These asymmetries could allow detection of CP violation in stop decays via spin correlations with the second lightest neutralino at the LHC, providing an alternative to constraints from electric dipole moments. Large asymmetries and sensitivity to the CP phases are possible, and a detailed experimental analysis is motivated.
This document discusses principles of relative and absolute dating of geologic events.
[1] Relative dating involves determining the sequence of events without knowing exact ages, by applying principles like superposition, cross-cutting relationships, and inclusion. Absolute dating determines exact ages in years using radiometric dating techniques that rely on radioactive decay of isotopes like carbon-14 and uranium-238.
[2] Five diagrams are presented and labeled for practice determining the sequence of rock layers, faults, and unconformities using relative dating principles. Radiometric dating equations are also shown relating radioactive parents and stable daughter isotopes to calculate the time since a rock formed.
1) The Fermi bubbles are giant gamma-ray emitting structures extending above and below the galactic center.
2) The bubbles may have been formed by periodic capture of stars by the supermassive black hole at the galactic center, releasing energy of around 3x10^52 ergs per capture.
3) This energy injection could produce very hot plasma, accelerating electrons that produce radio and gamma-ray emission through synchrotron radiation and inverse Compton scattering.
The OPERA experiment measures the velocity of neutrinos produced at CERN and detected 730 km away at the Gran Sasso laboratory to high precision. To do so it must accurately measure the time of flight of neutrinos between the two sites by precisely synchronizing clocks at CERN and Gran Sasso, determining the baseline distance through geodesy, and calibrating the timing of the proton beam and neutrino detection. This allows OPERA to search for small deviations from the speed of light in the measurement of the neutrino velocity.
1) The document describes small-scale graben (extensional faults) discovered on the Moon using images from the Lunar Reconnaissance Orbiter Camera.
2) Some graben are located near lobate scarps (contractional faults), while others are found in mare basalts and in the highlands.
3) The graben crosscut small impact craters, suggesting they formed recently, within the last 50 million years. This indicates the Moon has experienced recent extensional tectonic activity.
Teachable moment the japan earthquake and tsunamiSérgio Sacani
On March 11, 2011, a 9.0 magnitude earthquake struck off the coast of Honshu, Japan, generating a powerful tsunami. This was one of the largest earthquakes in Japanese history and caused widespread damage. The earthquake and tsunami highlighted Japan's vulnerability to natural disasters due to its location at the boundary of four tectonic plates.
Stefano Sposetti and Marco Iten detected a probable lunar impact event on February 11, 2011 while monitoring the moon from two separate observatories in Switzerland. Their videos showed a flash of light on the lunar surface at 20:36:58 UTC. Analysis of the light curves and location of the flash place the impact in a region of craters near 86°W, 16°N. The editorial board of Selenology Today notes that images from the Lunar Reconnaissance Orbiter before and after the reported event can be searched to look for an impact crater at the reported coordinates.
1. INTEGRAL observations of the SNR IC443 region detected several sources, including the pulsar wind nebula (Src #5) and the enigmatic hard X-ray source Src #11.
2. JEM-X images in the 6-10 and 10-20 keV bands tentatively identified counterparts for Src #5 and Src #11. Measured fluxes from JEM-X were consistent with XMM spectra but did not provide strong constraints.
3. Optical and infrared images showed possible counterparts for Src #11, including point sources and diffuse 2MASS-Ks emission thought to originate from shocked molecular hydrogen, suggesting a correlation between X-ray and infrared emission.
Vegetti et al. discovered a satellite galaxy located around a more distant elliptical galaxy acting as a gravitational lens. They were able to detect the satellite galaxy through its effect on distorting light from a background source, causing detectable "dents and blobs" in the ring of light formed by the main lens galaxy. This satellite galaxy has a mass of about 113 million solar masses, making it one of the lowest-mass satellite galaxies detected so far. The discovery provides evidence that gravitational lensing techniques can be used to find satellite galaxies beyond the Local Group and help test theories of galaxy formation and evolution.
Measurement of lmpulsive Thrust from a Closed Radio Frequency Cavity in VacuumSérgio Sacani
A vacuum test campaign evaluating the impulsive thrust performance of a tapered RF test article excited in the TM212 mode at 1,937 megahertz (MHz) has been completed. The test campaign consisted of a forward thrust phase and reverse thrust phase at less than 8 x 10-6 Torr vacuum with power scans at 40 watts, 60 watts, and 80 watts. The test campaign included a null thrust test effort to identify any mundane sources of impulsive thrust, however none were identified. Thrust data from forward, reverse, and null suggests that the system is consistently performing with a thrust to power ratio of 1.2 ± 0.1 mN/kW.
The document summarizes the quark model proposed in 1964 to describe the internal structure of hadrons such as protons and neutrons. It states that all hadrons are composed of more fundamental particles called quarks, which come in three flavors: up, down, and strange. The model was later expanded to incorporate three colors and additional quark flavors as more particles were discovered. The quark model provided explanations for experimental findings and made accurate predictions that were later verified, gaining broad acceptance.
Lattice Energy LLC Changes in Solar Neutrino Fluxes Alter Nuclear Beta-decay ...Lewis Larsen
This document discusses a new theory of nucleosynthesis proposed by Lattice Energy LLC. The theory suggests that nucleosynthesis may occur in many locations beyond just stellar cores, fission reactors, and supernovae. It highlights evidence that nucleosynthesis could take place in places like the solar photosphere, corona, and flux tubes as well as in phenomena like lightning. The theory also suggests that solar neutrino fluxes may alter beta decay rates on Earth. If true, this new understanding of nucleosynthesis would significantly change current astrophysical paradigms.
Topic 7.3 - The structure of matter.pptxHashemYamani
This document provides an overview of particle physics and the standard model of particle interactions. It discusses the fundamental particles that make up matter, including quarks, leptons, and force carriers. Quarks combine to form hadrons like protons and neutrons, while leptons include electrons. Particles are classified according to their interactions via the strong, weak, electromagnetic, and gravitational forces. Conservation laws like charge, baryon number, and lepton number must be obeyed in particle reactions. The Higgs boson is described as giving other particles their mass through interactions with the Higgs field.
Particle physics studies the fundamental constituents of matter and the interactions between them. Protons and neutrons are composed of quarks, which have fractional electric charges and come in six flavors. Quarks and leptons also have corresponding antiparticles. Particles interact through four fundamental forces carried by force carrier particles - the photon for electromagnetism, gluons for the strong force, and W/Z bosons for the weak force. Theories propose all forces arise from an exchange of these carrier particles between matter particles.
Unknown 2019 - expand “explorations at and beyond the neutron dripline ”LinhBui343479
The EXPAND project aims to investigate the structure of light neutron-rich nuclei near and beyond the neutron dripline using the RIBF facility at RIKEN. It focuses on augmenting the neutron detection capabilities of the existing SAMURAI setup by transforming the two-wall NEBULA array into the NEBULA-Plus four-wall array. This will enable the routine detection of 3 and 4 neutrons and significantly increase single and two-neutron detection efficiencies. The project has faced delays and budget issues but now plans to equip 60-70 of the 90 acquired scintillator modules for NEBULA-Plus within the existing budget to provide significant gains in neutron detection capabilities.
This document reviews prospects for detecting dark matter particles at the LHC and compares them to prospects for direct and indirect astrophysical dark matter searches. It summarizes that LHC searches may have good chances to observe supersymmetry in the near future, and direct astrophysical dark matter searches may also detect dark matter particles. The document then analyzes constraints on supersymmetric models from theoretical considerations and experimental data to identify preferred regions of parameter space for the lightest supersymmetric particle to be a dark matter candidate consistent with cosmological dark matter density measurements.
Rings in the_haloes_of_planetary_nebulaeSérgio Sacani
This document presents the discovery of ring structures in the haloes of eight planetary nebulae, tripling the number known to have such rings. The rings are analyzed using image processing techniques to enhance their visibility. They find ring spacings range from less than 0.01 pc to 0.06 pc. This suggests ring spacing increases with time after the asymptotic giant branch phase. The properties of the rings support predictions of dust-driven wind instability models of mass loss but do not rule out other models. Analyzing the new detections provides insights into mass modulation processes late in stellar evolution.
AN INTRODUCTION TO BASIC PHENOMENA OF PLASMA PHYSICSDr. Ved Nath Jha
Plasma is a set of neutral and charged particles which reveals a number of collective behaviors. The very
long range coulomb forces enable the charged particles in plasma to work together with one another
simultaneously. The study of plasma is actually a really ancient area of investigation in plasma physics
and it remains to be among the vital fields due to the crucial role of its in most plasma uses including
plasma processing, fabrication of semiconductor systems, etching, etc. except the presence of just ions
and electrons, the plasma in many instances, has a number of other species of ions like negative ions
which impact the complete plasma behaviour. Within this paper we study about the fundamental ideas of
plasma physics.
This document discusses interference and diffraction of light waves. It begins by introducing Young's double slit experiment and discussing how it demonstrates the wave nature of light through superposition. It then discusses why two slits are used, explaining that single light sources cannot maintain a constant phase difference due to thermal agitation. It also discusses how diffraction occurs when a plane wave passes through a slit and produces an interference pattern on a screen. The document compares interference and diffraction, and discusses how diffraction can be used to prove the uncertainty principle of quantum mechanics. It concludes by discussing how gravity can cause decoherence in double slit experiments and briefly summarizing G.P. Thomson's experiment using electron diffraction through thin metal films.
The document discusses particle physics and compares it to concepts in Jainology. It summarizes current knowledge in particle physics including the three families of elementary particles - quarks, leptons, and gauge bosons. It outlines future areas of research in particle physics like determining particle masses and the nature of dark matter. The document then explains similar concepts in Jainology like paramanu being the most fundamental particle and that Jain concepts could enhance understanding of areas still unknown in particle physics like dark matter and provide insights into other scientific domains.
1) The document discusses the Maxwell-Boltzmann distribution, which describes the distribution of velocities or energies of particles in a gas. Maxwell and Boltzmann developed this distribution based on assumptions about molecular motion in gases.
2) The Maxwell-Boltzmann distribution can be derived using statistical mechanics and considering the multiplicity, or number of arrangements, of particles into different energy states. Maximizing the multiplicity subject to conservation constraints leads to the Maxwell-Boltzmann distribution.
3) The derivation utilizes concepts such as the density of states function, integrals over energy states, and results in identifying temperature as proportional to the average kinetic energy per particle divided by the Boltzmann constant.
CHAPTER 5 Wave Properties of Matter and Quantum Mechanics I
5.1 X-Ray Scattering (review and some more material)
5.2 De Broglie Waves
5.3 Electron Scattering / Transmission electron microscopy
5.4 Wave Motion
5.5 Waves or Particles?
5.6 Uncertainty Principle
5.7 Probability, Wave Functions, and the Copenhagen Interpretation
5.8 Particle in a Box
1) The Fermi bubbles are giant gamma-ray emitting structures extending above and below the galactic center.
2) The bubbles may have been formed by periodic capture of stars by the supermassive black hole at the galactic center, releasing energy of around 3x10^52 ergs per capture.
3) This energy injection could produce very hot plasma, accelerating electrons that produce radio and gamma-ray emission through synchrotron radiation and inverse Compton scattering.
The OPERA experiment measures the velocity of neutrinos produced at CERN and detected 730 km away at the Gran Sasso laboratory to high precision. To do so it must accurately measure the time of flight of neutrinos between the two sites by precisely synchronizing clocks at CERN and Gran Sasso, determining the baseline distance through geodesy, and calibrating the timing of the proton beam and neutrino detection. This allows OPERA to search for small deviations from the speed of light in the measurement of the neutrino velocity.
1) The document describes small-scale graben (extensional faults) discovered on the Moon using images from the Lunar Reconnaissance Orbiter Camera.
2) Some graben are located near lobate scarps (contractional faults), while others are found in mare basalts and in the highlands.
3) The graben crosscut small impact craters, suggesting they formed recently, within the last 50 million years. This indicates the Moon has experienced recent extensional tectonic activity.
Teachable moment the japan earthquake and tsunamiSérgio Sacani
On March 11, 2011, a 9.0 magnitude earthquake struck off the coast of Honshu, Japan, generating a powerful tsunami. This was one of the largest earthquakes in Japanese history and caused widespread damage. The earthquake and tsunami highlighted Japan's vulnerability to natural disasters due to its location at the boundary of four tectonic plates.
Stefano Sposetti and Marco Iten detected a probable lunar impact event on February 11, 2011 while monitoring the moon from two separate observatories in Switzerland. Their videos showed a flash of light on the lunar surface at 20:36:58 UTC. Analysis of the light curves and location of the flash place the impact in a region of craters near 86°W, 16°N. The editorial board of Selenology Today notes that images from the Lunar Reconnaissance Orbiter before and after the reported event can be searched to look for an impact crater at the reported coordinates.
1. INTEGRAL observations of the SNR IC443 region detected several sources, including the pulsar wind nebula (Src #5) and the enigmatic hard X-ray source Src #11.
2. JEM-X images in the 6-10 and 10-20 keV bands tentatively identified counterparts for Src #5 and Src #11. Measured fluxes from JEM-X were consistent with XMM spectra but did not provide strong constraints.
3. Optical and infrared images showed possible counterparts for Src #11, including point sources and diffuse 2MASS-Ks emission thought to originate from shocked molecular hydrogen, suggesting a correlation between X-ray and infrared emission.
Vegetti et al. discovered a satellite galaxy located around a more distant elliptical galaxy acting as a gravitational lens. They were able to detect the satellite galaxy through its effect on distorting light from a background source, causing detectable "dents and blobs" in the ring of light formed by the main lens galaxy. This satellite galaxy has a mass of about 113 million solar masses, making it one of the lowest-mass satellite galaxies detected so far. The discovery provides evidence that gravitational lensing techniques can be used to find satellite galaxies beyond the Local Group and help test theories of galaxy formation and evolution.
Measurement of lmpulsive Thrust from a Closed Radio Frequency Cavity in VacuumSérgio Sacani
A vacuum test campaign evaluating the impulsive thrust performance of a tapered RF test article excited in the TM212 mode at 1,937 megahertz (MHz) has been completed. The test campaign consisted of a forward thrust phase and reverse thrust phase at less than 8 x 10-6 Torr vacuum with power scans at 40 watts, 60 watts, and 80 watts. The test campaign included a null thrust test effort to identify any mundane sources of impulsive thrust, however none were identified. Thrust data from forward, reverse, and null suggests that the system is consistently performing with a thrust to power ratio of 1.2 ± 0.1 mN/kW.
The document summarizes the quark model proposed in 1964 to describe the internal structure of hadrons such as protons and neutrons. It states that all hadrons are composed of more fundamental particles called quarks, which come in three flavors: up, down, and strange. The model was later expanded to incorporate three colors and additional quark flavors as more particles were discovered. The quark model provided explanations for experimental findings and made accurate predictions that were later verified, gaining broad acceptance.
Lattice Energy LLC Changes in Solar Neutrino Fluxes Alter Nuclear Beta-decay ...Lewis Larsen
This document discusses a new theory of nucleosynthesis proposed by Lattice Energy LLC. The theory suggests that nucleosynthesis may occur in many locations beyond just stellar cores, fission reactors, and supernovae. It highlights evidence that nucleosynthesis could take place in places like the solar photosphere, corona, and flux tubes as well as in phenomena like lightning. The theory also suggests that solar neutrino fluxes may alter beta decay rates on Earth. If true, this new understanding of nucleosynthesis would significantly change current astrophysical paradigms.
Topic 7.3 - The structure of matter.pptxHashemYamani
This document provides an overview of particle physics and the standard model of particle interactions. It discusses the fundamental particles that make up matter, including quarks, leptons, and force carriers. Quarks combine to form hadrons like protons and neutrons, while leptons include electrons. Particles are classified according to their interactions via the strong, weak, electromagnetic, and gravitational forces. Conservation laws like charge, baryon number, and lepton number must be obeyed in particle reactions. The Higgs boson is described as giving other particles their mass through interactions with the Higgs field.
Particle physics studies the fundamental constituents of matter and the interactions between them. Protons and neutrons are composed of quarks, which have fractional electric charges and come in six flavors. Quarks and leptons also have corresponding antiparticles. Particles interact through four fundamental forces carried by force carrier particles - the photon for electromagnetism, gluons for the strong force, and W/Z bosons for the weak force. Theories propose all forces arise from an exchange of these carrier particles between matter particles.
Unknown 2019 - expand “explorations at and beyond the neutron dripline ”LinhBui343479
The EXPAND project aims to investigate the structure of light neutron-rich nuclei near and beyond the neutron dripline using the RIBF facility at RIKEN. It focuses on augmenting the neutron detection capabilities of the existing SAMURAI setup by transforming the two-wall NEBULA array into the NEBULA-Plus four-wall array. This will enable the routine detection of 3 and 4 neutrons and significantly increase single and two-neutron detection efficiencies. The project has faced delays and budget issues but now plans to equip 60-70 of the 90 acquired scintillator modules for NEBULA-Plus within the existing budget to provide significant gains in neutron detection capabilities.
This document reviews prospects for detecting dark matter particles at the LHC and compares them to prospects for direct and indirect astrophysical dark matter searches. It summarizes that LHC searches may have good chances to observe supersymmetry in the near future, and direct astrophysical dark matter searches may also detect dark matter particles. The document then analyzes constraints on supersymmetric models from theoretical considerations and experimental data to identify preferred regions of parameter space for the lightest supersymmetric particle to be a dark matter candidate consistent with cosmological dark matter density measurements.
Rings in the_haloes_of_planetary_nebulaeSérgio Sacani
This document presents the discovery of ring structures in the haloes of eight planetary nebulae, tripling the number known to have such rings. The rings are analyzed using image processing techniques to enhance their visibility. They find ring spacings range from less than 0.01 pc to 0.06 pc. This suggests ring spacing increases with time after the asymptotic giant branch phase. The properties of the rings support predictions of dust-driven wind instability models of mass loss but do not rule out other models. Analyzing the new detections provides insights into mass modulation processes late in stellar evolution.
AN INTRODUCTION TO BASIC PHENOMENA OF PLASMA PHYSICSDr. Ved Nath Jha
Plasma is a set of neutral and charged particles which reveals a number of collective behaviors. The very
long range coulomb forces enable the charged particles in plasma to work together with one another
simultaneously. The study of plasma is actually a really ancient area of investigation in plasma physics
and it remains to be among the vital fields due to the crucial role of its in most plasma uses including
plasma processing, fabrication of semiconductor systems, etching, etc. except the presence of just ions
and electrons, the plasma in many instances, has a number of other species of ions like negative ions
which impact the complete plasma behaviour. Within this paper we study about the fundamental ideas of
plasma physics.
This document discusses interference and diffraction of light waves. It begins by introducing Young's double slit experiment and discussing how it demonstrates the wave nature of light through superposition. It then discusses why two slits are used, explaining that single light sources cannot maintain a constant phase difference due to thermal agitation. It also discusses how diffraction occurs when a plane wave passes through a slit and produces an interference pattern on a screen. The document compares interference and diffraction, and discusses how diffraction can be used to prove the uncertainty principle of quantum mechanics. It concludes by discussing how gravity can cause decoherence in double slit experiments and briefly summarizing G.P. Thomson's experiment using electron diffraction through thin metal films.
The document discusses particle physics and compares it to concepts in Jainology. It summarizes current knowledge in particle physics including the three families of elementary particles - quarks, leptons, and gauge bosons. It outlines future areas of research in particle physics like determining particle masses and the nature of dark matter. The document then explains similar concepts in Jainology like paramanu being the most fundamental particle and that Jain concepts could enhance understanding of areas still unknown in particle physics like dark matter and provide insights into other scientific domains.
1) The document discusses the Maxwell-Boltzmann distribution, which describes the distribution of velocities or energies of particles in a gas. Maxwell and Boltzmann developed this distribution based on assumptions about molecular motion in gases.
2) The Maxwell-Boltzmann distribution can be derived using statistical mechanics and considering the multiplicity, or number of arrangements, of particles into different energy states. Maximizing the multiplicity subject to conservation constraints leads to the Maxwell-Boltzmann distribution.
3) The derivation utilizes concepts such as the density of states function, integrals over energy states, and results in identifying temperature as proportional to the average kinetic energy per particle divided by the Boltzmann constant.
CHAPTER 5 Wave Properties of Matter and Quantum Mechanics I
5.1 X-Ray Scattering (review and some more material)
5.2 De Broglie Waves
5.3 Electron Scattering / Transmission electron microscopy
5.4 Wave Motion
5.5 Waves or Particles?
5.6 Uncertainty Principle
5.7 Probability, Wave Functions, and the Copenhagen Interpretation
5.8 Particle in a Box
The document summarizes key concepts about crystalline and amorphous solids, including:
- Crystalline solids exhibit long-range order while amorphous solids only have short-range order.
- Ionic crystals like NaCl and CsCl form face-centered cubic or body-centered cubic structures to maximize interactions between oppositely charged ions.
- The cohesive energy of ionic crystals can be calculated by considering contributions from Coulomb attraction, electron overlap repulsion, ionization energies, and electron affinities.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
A herschel and_apex_census_of_the_reddest_sources_in_orion_searching_for_the_...Sérgio Sacani
This document summarizes a study that uses Herschel and APEX data to identify the reddest, youngest protostar candidates in the Orion molecular clouds. 55 new protostar candidates are detected at 70 and 160 microns that were too faint or undetected at 24 microns in previous Spitzer data. The 11 reddest candidates with log(70 micron flux / 24 micron flux) > 1.65 are considered reliable protostars, while the remaining 44 have less extreme colors and higher contamination potential. Combining these with previously known protostars yields 18 sources called PACS Bright Red sources (PBRs) with the reddest colors. Analysis finds the PBRs have properties of very young Class 0 sources like
The document discusses the scientific method and how it has evolved over time. It begins by defining science as the empirical study of nature. It then discusses three main methodologies in science: reductionism, which explains phenomena in terms of underlying mechanisms; structuralism, which studies complex phenomena as original systems; and "universalism", which makes statistical predictions about classes of similar systems. The document traces how these methodologies have developed from classical physics to modern fields like quantum mechanics and biology. It also explores how mythologies can provide metaphorical insights that inspire scientific hypotheses.
Organic chemistry has two main divisions. One division deals with aliphatic (fatty) compounds, the first compounds you encountered in Organic Chemistry I. The second division includes the aromatic (fragrant) compounds, of which benzene is a typical example.
The document discusses string theory, extra dimensions, and cosmology. It notes that inflation and dark energy require new physics beyond general relativity and quantum field theory. Most string cosmology models invoke string theory, branes, or extra dimensions as approximations of string theory solutions. However, reliably anchoring cosmology in string theory has proven difficult, with success being rare. While cosmological observations can't determine the nature of dark energy, understanding fundamental physics through experiments like the LHC remains a key hope.
Structure Of Atom_STUDY MATERIALS_JEE-MAIN_AIPMTSupratim Das
1. Dalton's atomic theory proposed that atoms are indivisible, hard spheres that differ in properties based on their unique structure.
2. Rutherford's gold foil experiment showed that atoms have a small, dense nucleus containing their mass, with electrons orbiting the nucleus.
3. Bohr used Planck's quantum theory to explain electron orbits in hydrogen atoms, stabilizing Rutherford's model and beginning modern atomic theory.
Compositions of iron-meteorite parent bodies constrainthe structure of the pr...Sérgio Sacani
Magmatic iron-meteorite parent bodies are the earliest planetesimals in the Solar System,and they preserve information about conditions and planet-forming processes in thesolar nebula. In this study, we include comprehensive elemental compositions andfractional-crystallization modeling for iron meteorites from the cores of five differenti-ated asteroids from the inner Solar System. Together with previous results of metalliccores from the outer Solar System, we conclude that asteroidal cores from the outerSolar System have smaller sizes, elevated siderophile-element abundances, and simplercrystallization processes than those from the inner Solar System. These differences arerelated to the formation locations of the parent asteroids because the solar protoplane-tary disk varied in redox conditions, elemental distributions, and dynamics at differentheliocentric distances. Using highly siderophile-element data from iron meteorites, wereconstruct the distribution of calcium-aluminum-rich inclusions (CAIs) across theprotoplanetary disk within the first million years of Solar-System history. CAIs, the firstsolids to condense in the Solar System, formed close to the Sun. They were, however,concentrated within the outer disk and depleted within the inner disk. Future modelsof the structure and evolution of the protoplanetary disk should account for this dis-tribution pattern of CAIs.
Signatures of wave erosion in Titan’s coastsSérgio Sacani
The shorelines of Titan’s hydrocarbon seas trace flooded erosional landforms such as river valleys; however, it isunclear whether coastal erosion has subsequently altered these shorelines. Spacecraft observations and theo-retical models suggest that wind may cause waves to form on Titan’s seas, potentially driving coastal erosion,but the observational evidence of waves is indirect, and the processes affecting shoreline evolution on Titanremain unknown. No widely accepted framework exists for using shoreline morphology to quantitatively dis-cern coastal erosion mechanisms, even on Earth, where the dominant mechanisms are known. We combinelandscape evolution models with measurements of shoreline shape on Earth to characterize how differentcoastal erosion mechanisms affect shoreline morphology. Applying this framework to Titan, we find that theshorelines of Titan’s seas are most consistent with flooded landscapes that subsequently have been eroded bywaves, rather than a uniform erosional process or no coastal erosion, particularly if wave growth saturates atfetch lengths of tens of kilometers.
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
�
(
�
−
�
)
∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
000
±
2
,
000
km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
�
Ca-rich population. Although such an object is too red for any low-
�
cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
≲
1
�
) with
Λ
CDM. Therefore unlike low-
�
Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
�
truly diverge from their low-
�
counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary S...Sérgio Sacani
Wereport the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the R–I spectral index by 1.0 ±0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ287 as well as the dense monitoring sample of Krakow.
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Sérgio Sacani
Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H−K and K−L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (≈15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20◦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holes– stars: formation– Galaxy: center– galaxies: star formation
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
Anti-Universe And Emergent Gravity and the Dark UniverseSérgio Sacani
Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law for entanglement entropy. The extension to de Sitter space requires taking into account the entropy and temperature associated with the cosmological horizon. Using insights from string theory, black hole physics and quantum information theory we argue that the positive dark energy leads to a thermal volume law contribution to the entropy that overtakes the area law precisely at the cosmological horizon. Due to the competition between area and volume law entanglement the microscopic de Sitter states do not thermalise at sub-Hubble scales: they exhibit memory effects in the form of an entropy displacement caused by matter. The emergent laws of gravity contain an additional ‘dark’ gravitational force describing the ‘elastic’ response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newton’s constant and the Hubble acceleration scale a0 = cH0, and provide evidence for the fact that this additional ‘dark gravity force’ explains the observed phenomena in galaxies and clusters currently attributed to dark matter.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Tr...Sérgio Sacani
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the
atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets
receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric
composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet
transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (Porb) of 12.76 days.
The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous Porb from TESS data. We
confirmed the transit signal and Porb using ground-based photometry with MuSCAT2 and MuSCAT3, and
validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as
well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope
and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host
star is inactive, with an X-ray-to-bolometric luminosity ratio of log 5.7 L L X bol » - . Joint analysis of the light
curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R⊕,a3σ mass upper limit of
3.9 M⊕, and an equilibrium temperature of 315 ± 6 K assuming zero albedo. The transmission spectroscopy metric
(TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small
list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Sérgio Sacani
We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a
bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from the Solar system with one of the
lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors
42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations
with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory,
as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of
12.76144 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 K. Gliese 12 b has excellent
future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar
compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool
stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy.
The importance of continents, oceans and plate tectonics for the evolution of...Sérgio Sacani
Within the uncertainties of involved astronomical and biological parameters, the Drake Equation
typically predicts that there should be many exoplanets in our galaxy hosting active, communicative
civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is
often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing
the importance of planetary tectonic style for biological evolution. We summarize growing evidence
that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern
plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated
emergence and evolution of complex species. We further suggest that both continents and oceans
are required for ACCs because early evolution of simple life must happen in water but late evolution
of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox
(1) by adding two additional terms to the Drake Equation: foc
(the fraction of habitable exoplanets
with significant continents and oceans) and fpt
(the fraction of habitable exoplanets with significant
continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by
demonstrating that the product of foc
and fpt
is very small (< 0.00003–0.002). We propose that the lack
of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on
exoplanets with primitive life.
A Giant Impact Origin for the First Subduction on EarthSérgio Sacani
Hadean zircons provide a potential record of Earth's earliest subduction 4.3 billion years ago. Itremains enigmatic how subduction could be initiated so soon after the presumably Moon‐forming giant impact(MGI). Earlier studies found an increase in Earth's core‐mantle boundary (CMB) temperature due to theaccumulation of the impactor's core, and our recent work shows Earth's lower mantle remains largely solid, withsome of the impactor's mantle potentially surviving as the large low‐shear velocity provinces (LLSVPs). Here,we show that a hot post‐impact CMB drives the initiation of strong mantle plumes that can induce subductioninitiation ∼200 Myr after the MGI. 2D and 3D thermomechanical computations show that a high CMBtemperature is the primary factor triggering early subduction, with enrichment of heat‐producing elements inLLSVPs as another potential factor. The models link the earliest subduction to the MGI with implications forunderstanding the diverse tectonic regimes of rocky planets.
Climate extremes likely to drive land mammal extinction during next supercont...Sérgio Sacani
Mammals have dominated Earth for approximately 55 Myr thanks to their
adaptations and resilience to warming and cooling during the Cenozoic. All
life will eventually perish in a runaway greenhouse once absorbed solar
radiation exceeds the emission of thermal radiation in several billions of
years. However, conditions rendering the Earth naturally inhospitable to
mammals may develop sooner because of long-term processes linked to
plate tectonics (short-term perturbations are not considered here). In
~250 Myr, all continents will converge to form Earth’s next supercontinent,
Pangea Ultima. A natural consequence of the creation and decay of Pangea
Ultima will be extremes in pCO2 due to changes in volcanic rifting and
outgassing. Here we show that increased pCO2, solar energy (F⨀;
approximately +2.5% W m−2 greater than today) and continentality (larger
range in temperatures away from the ocean) lead to increasing warming
hostile to mammalian life. We assess their impact on mammalian
physiological limits (dry bulb, wet bulb and Humidex heat stress indicators)
as well as a planetary habitability index. Given mammals’ continued survival,
predicted background pCO2 levels of 410–816 ppm combined with increased
F⨀ will probably lead to a climate tipping point and their mass extinction.
The results also highlight how global landmass configuration, pCO2 and F⨀
play a critical role in planetary habitability.
Fueling AI with Great Data with Airbyte WebinarZilliz
This talk will focus on how to collect data from a variety of sources, leveraging this data for RAG and other GenAI use cases, and finally charting your course to productionalization.
Skybuffer SAM4U tool for SAP license adoptionTatiana Kojar
Manage and optimize your license adoption and consumption with SAM4U, an SAP free customer software asset management tool.
SAM4U, an SAP complimentary software asset management tool for customers, delivers a detailed and well-structured overview of license inventory and usage with a user-friendly interface. We offer a hosted, cost-effective, and performance-optimized SAM4U setup in the Skybuffer Cloud environment. You retain ownership of the system and data, while we manage the ABAP 7.58 infrastructure, ensuring fixed Total Cost of Ownership (TCO) and exceptional services through the SAP Fiori interface.
Essentials of Automations: Exploring Attributes & Automation ParametersSafe Software
Building automations in FME Flow can save time, money, and help businesses scale by eliminating data silos and providing data to stakeholders in real-time. One essential component to orchestrating complex automations is the use of attributes & automation parameters (both formerly known as “keys”). In fact, it’s unlikely you’ll ever build an Automation without using these components, but what exactly are they?
Attributes & automation parameters enable the automation author to pass data values from one automation component to the next. During this webinar, our FME Flow Specialists will cover leveraging the three types of these output attributes & parameters in FME Flow: Event, Custom, and Automation. As a bonus, they’ll also be making use of the Split-Merge Block functionality.
You’ll leave this webinar with a better understanding of how to maximize the potential of automations by making use of attributes & automation parameters, with the ultimate goal of setting your enterprise integration workflows up on autopilot.
Discover top-tier mobile app development services, offering innovative solutions for iOS and Android. Enhance your business with custom, user-friendly mobile applications.
Conversational agents, or chatbots, are increasingly used to access all sorts of services using natural language. While open-domain chatbots - like ChatGPT - can converse on any topic, task-oriented chatbots - the focus of this paper - are designed for specific tasks, like booking a flight, obtaining customer support, or setting an appointment. Like any other software, task-oriented chatbots need to be properly tested, usually by defining and executing test scenarios (i.e., sequences of user-chatbot interactions). However, there is currently a lack of methods to quantify the completeness and strength of such test scenarios, which can lead to low-quality tests, and hence to buggy chatbots.
To fill this gap, we propose adapting mutation testing (MuT) for task-oriented chatbots. To this end, we introduce a set of mutation operators that emulate faults in chatbot designs, an architecture that enables MuT on chatbots built using heterogeneous technologies, and a practical realisation as an Eclipse plugin. Moreover, we evaluate the applicability, effectiveness and efficiency of our approach on open-source chatbots, with promising results.
Northern Engraving | Nameplate Manufacturing Process - 2024Northern Engraving
Manufacturing custom quality metal nameplates and badges involves several standard operations. Processes include sheet prep, lithography, screening, coating, punch press and inspection. All decoration is completed in the flat sheet with adhesive and tooling operations following. The possibilities for creating unique durable nameplates are endless. How will you create your brand identity? We can help!
Monitoring and Managing Anomaly Detection on OpenShift.pdfTosin Akinosho
Monitoring and Managing Anomaly Detection on OpenShift
Overview
Dive into the world of anomaly detection on edge devices with our comprehensive hands-on tutorial. This SlideShare presentation will guide you through the entire process, from data collection and model training to edge deployment and real-time monitoring. Perfect for those looking to implement robust anomaly detection systems on resource-constrained IoT/edge devices.
Key Topics Covered
1. Introduction to Anomaly Detection
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12. Jupyter Notebooks with Code Examples
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Your One-Stop Shop for Python Success: Top 10 US Python Development Providers
Peron star
1. Preon Trinity - a new model of leptons and
quarks 1
Jean-Jacques Dugne†, Sverker Fredriksson‡, Johan
Hansson‡ and Enrico Predazzi§
arXiv:hep-ph/9909569v3 12 Oct 1999
† Laboratoire de Physique Corpusculaire, Universit´ Blaise Pas-
e
cal, Clermont-Ferrand II, FR-63177 Aubi`re, France
e
‡ Department of Physics, Lule˚ University of Technology,
a
SE-97187 Lule˚ Sweden
a,
§ Department of Theoretical Physics, Universit´ di Torino,
a
IT-10125 Torino, Italy
Abstract. A new model for the substructure of quarks, lep-
tons and weak gauge bosons is discussed. It is based on three
fundamental and absolutely stable spin-1/2 preons. Its preon
flavour SU (3) symmetry leads to a prediction of nine quarks,
nine leptons and nine heavy vector bosons. One of the quarks
has charge −4e/3, and is speculated to be the top quark (whose
charge has not been measured). The flavour symmetry leads
to three conserved lepton numbers in all known weak processes,
except for some neutrinos, which might either oscillate or decay.
There is also a (Cabibbo) mixing of the d and s quarks due to
an internal preon-antipreon annihilation channel. An identical
channel exists inside the composite Z 0 , leading to a relation
between the Cabibbo and Weinberg mixing angles.
1. Introduction
In this talk I will present a new preon model where leptons, quarks and
heavy vector bosons are composite objects with a fairly simple inner struc-
1 Presented by S.F. at Beyond 99, Tegernsee, Germany, June 7-11, 1999; to be
published in the Proceedings
1
2. ture. It is the result of a collaboration between the universities of Clermont-
Ferrand, Torino and Lule˚ within an EU-sponsored network, where also
a
groups from Paris and Thessaloniki are involved in other projects.
Our inspiration has come from a certain fatigue with the standard model
and its rather complicated Higgs mechanism, but also from its phenomeno-
logical success, which has convinced us that “there is something more fun-
damental behind”. Let me therefore start by giving our favourite preon
arguments, and first two of a more general nature:
Why not?
It should be fully natural to speculate about compositeness, especially as
it is impossible to prove, by any means, that a particle is not composite!
So, why not composite preons? Well, pre-preons already exist (. . . in the
literature).
There is always a deeper layer. . .
History tells us that whenever a model of matter has become more and
more complicated without providing a deeper understanding, another layer
of fundamental particles has been suggested - and found. But another
lesson of history is that a vast majority of all researchers have treated the
currently known fundamental particles as the ultimate level, until the facts
have been obvious!
Among the more detailed arguments, we would like to list the following
(many of which, but not all, have been discussed before [1]):
(i) There are by now “too many” leptons and quarks. It is a puzzle why
God the Almighty would prefer twelve fundamental particles. The only
reason I can find is that he chose one per Apostle, but that would restrict
the standard model to Christianity, which seems a too limited scope. Three
is a more universally sacred number.
(ii) There is a pattern among the six leptons and six quarks, i.e., the
family structure. Historically, such patterns have led to ideas about com-
positeness, with the quark model as a typical example.
(iii) The mathematically least attractive features of the standard model
come from the fact that the weak interaction has gauge bosons that are
massive (as well as unstable and of different charges). In preon models, they
can be seen as composite states. The weak interaction is a “leakage” of
multi-preon states, in analogy to the nuclear force being mediated by quark-
antiquark states. If so, there is no fundamental electroweak unification
and no need for the Higgs mechanism (nor for multi-Higgs, higgsinos or
composite Higgs).
(iv) An overlooked hint is that most quarks and leptons are unstable,
which in our view disqualifies them as fundamental particles. Historically,
2
3. all decays of “elementary” particles have sooner or later been interpreted
in terms of more fundamental objects.
(v) There are mixings, transitions, or oscillations among some of the
“fundamental” particles, such as among some quarks, and also among neu-
¯
trinos. This reminds about the mixing of K0 and K0 , now being understood
in terms of quarks.
(vi) There are conserved quantum numbers such as lepton numbers and
weak isospin, which we do not understand. When isospin and strangeness
were introduced in particle physics, the explanation turned out to be in
terms of quarks and (partly) conserved quark flavours. One of the visions
for any preon model should be to reduce the flora of ad hoc quantum
numbers.
2. General preon considerations
Preon models have so far focused on explaining the lightest family of two
quarks (u and d) and two leptons (e and νe ) with as few preons as possible.
This means either a minimal number of (two) different preons, e.g., the
“rishons” [2, 3], or a minimal number of (two) preons inside a quark or
lepton, e.g., the “haplons” [4].
The two heavier families are either considered “excitations” of the light
one, or prescribed to have a completely different internal structure, e.g.,
with different numbers of preons inside different quarks. As a result, no sim-
ple, consistent and predictive preon model exists. Neither have preon mod-
els been able to explain the cornerstones of the standard model from preon
properties. Rather, lepton number conservation, the Cabibbo-Kobayashi-
Maskawa (CKM) mixings [5], and the similarities between leptons and
quarks, have either been left unexplained, or implemented on the preon
level.
Nevertheless, we have been much inspired by the work of others, when
formulating our model. In particular, we would like to mention that we
have stolen, and customised, the following ideas:
(i) the idea from the original SU (3) quark model by Gell-Mann and
Zweig [6] that all hadrons known in the early 1960s can be explained in
terms of only three light quarks, with a (broken) flavour-SU (3) symmetry;
(ii) the idea from the rishon model that members of the lightest family
have three preons each;
(iii) the idea from the haplon model that the members of the lightest
family can be built by one spin-1/2 and one spin-0 object;
(iv) the idea of diquark models [7] that quarks like to pair-up in tightly
bound spin-0 systems;
3
4. Table 1. Our “supersymmetric” preon scheme.
charge +e/3 −2e/3 +e/3
spin-1/2 preons α β δ
spin-0 (anti)dipreons ¯¯
(β δ) α¯
(¯ δ) α¯
(¯ β)
(v) the idea of supersymmetry that spin-1/2 objects have relatives with
spin 0, even if only in a phenomenological sense, such as the “supersym-
metry” between quarks and diquarks in mesons and baryons [7].
3. A trinity of preons
A preon model for six leptons and six quarks must have at least five different
preons in the sense of the haplon model, i.e., three with spin 1/2 and two
with spin 0, or vice versa. In order to get a more symmetric scheme it seems
reasonable to have three of each, giving nine leptons and nine quarks.
The spin-1/2 and spin-0 preons can be given pairwise identical charges,
which by “accident” are those of the three lightest quarks. In order to
bring down the number of preons, we suggest that the spin-0 ones are not
fundamental, but tightly bound “dipreon” pairs of the spin-1/2 preons.
Calling the preons α, β and δ, and giving them charges +e/3, −2e/3 and
+e/3 (for simplicity; there is an ambiguity between the names preon and
antipreon), we get the simple and symmetric scheme in Table 1. Each preon
has a partner, which is the dipreon formed by the other two (anti)preons.
This model leads to a surprisingly rich spectrum of predictions and
explanations connected to the standard model. But before building up lep-
tons, quarks and vector bosons by combining preons with dipreons and/or
their anti-particles, we list the properties of the preons themselves.
(i) Mass: In order to understand why only six leptons, six quarks and
three vector bosons have been seen, it is tempting to speculate that one of
the preons is superheavy, say the δ. The α and β are much lighter. The
“heaviness” of the δ preon hence plays the role of strangeness in the quark
model. It should be noted though, that the more bound a fundamental
particle is, the less precise is the definition of its mass. An illustrative
paradox is that dipreons containing the δ do not seem to be superheavy.
(ii) Spin and electric charge: These are just implemented on the preon
level. It might be worthwhile here to contemplate the fundamental differ-
4
5. ence between the α and δ preons. Maybe this is in terms of a different
magnetic charge, coupled to both electric charge and spin.
(iii) QCD colour: It is necessary to assume that all preons are colour-3∗
in normal QCD, in order to understand why leptons and vector bosons are
colour singlets and quarks colour triplets. The assignment 3∗ instead of 3
is again a technicality because of our definition of preons vs. antipreons.
Then also the (anti)dipreons in Table 1 are 3∗ (3 ⊗ 3 = 3∗ ⊕ 6).
(iv) Preon flavour: The preon flavour plays, at first sight, the same role
in this model as the quark flavours did in the original quark model, i.e., the
model has an approximate flavour-SU (3) symmetry. It cannot be exact for
masses and wave functions, but unlike the quark model, we suggest that
the net flavours are exactly conserved in nature, as a consequence of the
next point. Note that the preons are flavour-3, the dipreons 3∗ , and the
antidipreons 3.
(v) Absolute stability!: Unlike the situation for “fundamental” particles
in the conventional standard model, we assume that preons are absolutely
stable against decay. All weak decays in nature are therefore consequences
of a mere reshuffling of preons into particles with a lower total rest mass.
(vi) “Hypercolour”?: Most preon models rely on some new, superstrong
force that keeps leptons and quarks together. Assuming that it is QCD
like, it is usually called hyper-QCD or super-QCD, with hyper-gluons etc.
There are also suggestions that it might not be SU (3) symmetric, but obey
some more complicated group theory, such as SU (4).
It is noteworthy that no other preon quantum properties are needed in
order to understand all quantum numbers of leptons and quark. So, there
is no lepton number, no baryon number, no isospin, strangeness or weak
isospin on the preon level.
4. The leptons
Leptons are assumed to be three-preon states, in the form of a preon and a
dipreon, all in colour-singlet (3∗ ⊗ 3 = 1 ⊕ 8). We assume that colour-octet
leptons do not exist. The lepton scheme that we favour is given in Table 2.
Note that this matrix is set up as a rough scheme, without a deeper con-
sideration of what the actual preon wave functions would be, i.e., quantum-
mechanical mixings of the simple products of single-preon wave functions.
We will turn back to such questions later. Next we discuss the lepton
properties, point by point.
(i) All leptons are correctly reproduced with all their quantum num-
bers (except, possibly, helicity, since it is not obvious from the scheme why
neutrinos are left-handed and antineutrinos right-handed). There is an am-
biguity in the scheme, since it would work equally well with the “electron”
5
6. Table 2. Leptons as three-preon states.
(βδ) (αδ) (αβ)
α νe µ+ ντ
β e− νµ
¯ τ−
δ νκ1
¯ κ+ νκ2
¯
column interchanged with the “τ ” column. We will discuss this ambiguity
later.
(ii) There are three new (superheavy) leptons, all containing an “iso-
lated” δ preon. Two of these are neutrinos, which must be heavier than
half the Z 0 mass, in order not to violate the finding that there are only
three light neutrinos. These neutrinos must naturally be unstable.
(iii) There is no subscheme in terms of three lepton families. The only
mathematical structure is the one given by preon-flavour SU (3), which
splits up the nonet in one octet and one singlet, exactly like with the three-
quark baryon octet (3⊗3∗ = 8⊕1). When constructing true flavour-SU (3)
based wave functions the singlet is to be found as a linear combination of the
three neutrino cells on the main diagonal, while the other two combinations
are the lepton equivalents of the baryons Σ0 and Λ0 in the quark model.
(iv) The basic scheme contains the electron and the antimuon on equal
footing, and similarly for their neutrinos. This whets the appetite for
speculations that helicity has to do with the properties of the “naked”
preon outside the spin-0 dipreon.
(v) There is no simple mass-ordering in the scheme, which makes it a
much tougher challenge to find mass-formulas and a dynamics, than in the
quark model. One trend is that the mass increases along all diagonal lines
from upper left to lower right.
(vi) The three traditional lepton numbers are conserved in all well-
established processes. This mirrors the conservation of preon flavour. As to
the best of our knowledge, this is the only preon model that links the lepton
numbers, and the virtual three-family structure, to a more fundamental
¯ α¯
concept. Muon decay, µ− → νµ + e− + νe , is a typical example: α(¯ δ) →
¯
¯ αδ) + β(βδ) + α(β δ). The dipreon goes into the muon neutrino, while the
β(¯ ¯ ¯ ¯¯
preon hides inside a W − = β α, which then decays into the electron and its
¯
neutrino. All efforts to violate lepton number conservation by splitting up
the leptons differently lead to final states that violate energy conservation.
(vii) There is no general lepton number conservation! First of all, there
6
7. is no fourth lepton number connected to the superheavy κ and its two neu-
trinos. Rather, their decays must violate also the normal lepton numbers,
an illustrative example being: κ+ → µ+ + νe + ντ . ¯
(viii) An attractive aspect of the lack of a general lepton number conser-
vation is that the three neutrinos, νe , νµ and νκ2 along the main diagonal
¯ ¯
can mix quantum-mechanically, because they have identical preon contents,
differing only in the internal spin composition: νe = α(βδ), νµ = β(αδ) and
¯
νκ2 = δ(αβ). This brings up the issue of the ambiguity between the left-
¯
most and right-most columns in Table 2, since a shift of columns would
involve the ντ in the mixing, instead of the νe . A three-neutrino mix-
ing might induce neutrino oscillations, νe ↔ νµ ↔ νκ2 . But there could
¯ ¯
also be decays, like the electromagnetic νµ → νe + γ, or the more exotic
¯
νµ → νe + φ, where φ is a light scalar, such as a Goldstone boson, or a
¯
bound scalar preon-antipreon state, say (αα). The photon decay has been
¯
studied recently by one of us within the same formalism as the quark anal-
ogy Σ0 → Λ0 + γ [8], but no conclusion can be drawn about the neutrino
lifetime or the photon spectrum. Finally, it should be noted that it is the
antimuon neutrino that mixes with the electron (or tau) neutrino. This is
not obviously forbidden by helicity conservation, since massive neutrinos
have both left-handed and right-handed components. One can also think
of helicity-conserving oscillations, where the neutrino appearing with the
wrong helicity is sterile. Such sterile neutrinos are often needed in ambi-
tious efforts to fit all neutrino data in terms of oscillations.
(ix) A final, but important point, is that the lack of lepton number con-
servation cannot, in our scheme, allow for mixings of the charged leptons.
Such mixings can occur only if there is a more basic, quantum-mechanical
(“Cabibbo”) mixing of the α and δ preons inside leptons and quarks. That
would violate the exact conservation of three preon flavours, but cannot be
excluded, on the per mille level, by the experimental data. We will discuss
this issue again in connection to quarks.
5. The quarks
In a similar spirit as with the leptons, we now construct, in Table 3, the
quarks as bound states of a preon and an antidipreon in colour triplet
(3∗ ⊗ 3∗ = 3 ⊕ 6∗ ). Again, the contents of the cells are not meant to give
the exact preon wave functions of the quarks.
The following list of quark properties takes up several new features that
do not appear for leptons.
(i) All known quarks are correctly reproduced. There is no overall
ambiguity in the scheme.
7
8. Table 3. Quarks as preon-antidipreon states.
¯¯
(β δ) α¯
(¯ δ) α¯
(¯ β)
α u s c
β d X b
δ t? g h
(ii) There are three new quarks, but these are not obviously the ones
with an “isolated”, superheavy δ preon. Two of them belong to this cat-
egory, the g and h quarks (for “gross” and “heavy”), but the third (X) is
on the second line, and not clearly superheavy.
(iii) On the other hand, the top quark is among the superheavies, which
would explain why it is so much heavier than its conventionally assigned
partners, the b quark and the τ lepton. This would also give some hope
that “superheavy” in our model means around a few hundred GeV, which
would make the CERN LHC ideal for discovering the remaining leptons,
quarks and vector bosons. They might even be within reach of the Fermilab
Tevatron.
(iv) The quarks have no three-family grouping either, but here the
flavour-SU (3) decomposition is into a sextet and an anti-triplet (3 ⊗ 3 =
6 ⊕ 3∗ ). The anti-triplet contains the three quarks on the main diagonal,
while the other quarks form the sextet. Here it should be mentioned that a
flavour-sextet assignment for quarks has been suggested also by Davidson
et al. [9], and speculated to be a consequence of a preon substructure,
although without reference to any particular preon model.
(v) The appearance of the X quark with charge −4e/3 opens up for some
thrilling speculations. At first sight it should not be superheavy, since it
does not have a naked δ. However, the X belongs to a flavour antitriplet
together with the u and h, and different SU (3) representations can have
different mass formulas. Another idea is that a “light” X quark has escaped
discovery. Searches for new quarks seem to focus on a “fourth-family” b′
with charge −e/3 [10]. They rely on model-dependent assumptions on b′
decay [11] in ways that would make the suggested decay of the X “invisi-
ble”. Neither has there been searches for new resonances in e+ e− collisions
at high energies in the traditional way of fine-tuning the total energy in
small steps. It is, however, unlikely that a light X would not have been
detected in the search for the top quark [12]. The case for an X with a
mass below, say, the W mass is therefore weak.
(vi) A final speculation about the X is that it is indeed identical to the
8
9. discovered top quark. This idea cannot easily be dismissed, since there is
no measurement of the top charge [12]. The top quark was found through
its presumed main decay channels, namely semi-leptonic ones like t →
¯
b + ℓ+ + ν, or non-leptonic ones like t → b + u + d, where a few b quarks
have been “tagged” by a charged muon in semi-leptonic decays. However,
the situation is rather complex because a total event contains the decay of
¯
the full tt pair into several leptons and hadronic jets, and the identification
and matching of those are non-trivial. The corresponding decay channels
for the antiquark X would be X → ¯ + ℓ+ + ν and X → ¯ + u + d, so that
¯ ¯ b ¯ b ¯
the full X X ¯ decay would give the same leptons and jets as in a tt decay,
¯
although with a different b − W matching. A study along these lines [13]
shows that only a couple of events give a weak support for the conventional
charge, in the sense of χ2 fits to different jet identifications, while the bulk
of events are inconclusive. Hopefully, this issue will be settled soon at the
upgraded Tevatron, thanks to better statistics and also better possibilities
to study outgoing particles much closer to the interaction vertex. It is
interesting to note that also Chang et al. [14] have suggested that the
top charge is −4e/3, although within an analysis built on details of the
standard model that do not appear in our preon model (e.g., the Higgs
mechanism).
(vii) Quark decays are mostly similar to lepton decays, since they nor-
mally mean a regrouping of preons. An example is beta decay: d →
¯¯ ¯¯ ¯ ¯¯
u + e− + νe , which is β(β δ) → α(β δ) + β(βδ) + α(β δ). However, some
¯
quarks have pairwise identical net preon flavour, just like the three neu-
trinos discussed earlier. The best example is the d and s quarks, having
the flavour of the δ. This makes possible a quantum-mechanical mixing of
the two quarks, and another type of transition between them, compared
to normal quark decays. This is the preonic explanation of the Cabibbo
mechanism. An s ↔ d transition goes through annihilation channels like
¯
αα ↔ β β involving the “naked” preon and the corresponding antipreon
¯
inside the dipreon. No such channels exist for leptons, but as we will see
below, they are important also inside the preon-antipreon Z 0 . In terms of
wave functions and the notions of the Cabibbo theory, the d and s quarks
are the flavour-SU (3) eigenstates produced in preon processes, while the
mass eigenstates, d′ and s′ , relevant for weak decays, are mixtures of these
preon states, parametrised by the Cabibbo angle. As the Cabibbo mech-
anism is just put in “by hand” in the standard model, we regard this
connection between the preon substructure and the mixing of d and s one
of the most promising features of our model.
(viii) The smaller elements of the CKM matrix cannot be accounted
for by such preon annihilation channels, although it is noteworthy that
they are much smaller than the Cabibbo mixing, and hence might have
a different explanation. We point out that such effects can result from a
9
10. Table 4. Vector bosons as preon-antipreon states.
α
¯ ¯
β ¯
δ
α Z, Z ′ W+ Z ′′′
β W− Z ′, Z W ′−
δ Z ′′′ W ′+ Z ′′
very small quantum-mechanical mixing of the α and δ preons inside the
quark (and lepton) wave functions. This would mean that flavour-SU (3)
is heavily broken on the mass level (quark and lepton masses), somewhat
broken in wave functions (Cabibbo mixing), and just a little broken on the
quantum-number level (i.e., preon flavour is not exactly conserved). Again,
the situation is principally very similar to the early quark model.
6. The heavy vector bosons
The vector bosons are preon-antipreon states, as in several other preon
models. In our model there will be nine of them, as in Table 4.
The following observations can be made.
(i) This nonet is very similar to the vector mesons in the quark model
(ρ, ω, φ, K ∗ ). Some examples are: Both carry a “leakage force”, the weak
and nuclear ones; both Z 0 and ρ0 are heavier than their charged counter-
parts (which is rare in particle physics); and both Z 0 and ρ0 are believed
to mix with the photon, as described by the electroweak theory and the
vector meson dominance model. In the meson case it is acknowledged that
these phenomena are consequences of the quark structure, while for vector
bosons they are just put in by hand in the standard model, but are due to
preons in our model.
(ii) There are no known scalar counterparts to the vector bosons, al-
though these are expected in many preon models [1]. It is not known if they
are even heavier than the vector bosons, or have extremely weak couplings
to other particles, or are very light, but hidden inside scalar mesons as Fock
states. It is a crucial challenge to preon models to find these scalars.
(iii) The standard model concepts of weak isospin, Weinberg mixing etc
appear in this model on the same level as the Cabibbo and neutrino mix-
ings, i.e., as consequences of (broken) flavour-SU (3) on the preon level. In
Table 4, the hypothetical particle normally called W 0 (the weak isotriplet)
10
11. ¯ ¯
is the SU (3) eigenstate αα − β β, while the isosinglet B 0 is αα + β β (ne-
¯ ¯
glecting a possible admixture of the superheavy δ). The mass eigenstates,
Z and Z ′ , are mixtures of these, parametrised by the Weinberg angle. Note
that the state orthogonal to Z is not the photon, as in the standard model,
but the heavier Z ′ . This is more like the vector mesons, where the ω is
the heavier partner of the ρ0 . The difference between the W 0 and B 0
components of Z can be seen through decays, where the latter mode gives
access to preon-antipreon annihilation channels, identical to the ones inside
quarks. This makes it extremely tempting to speculate about a possible
relation between the Cabibbo angle for quarks and the Weinberg angle for
Z decays. We have found such a simple relation, but there are so many ifs
and buts in its proof that we will present it in a publication of its own.
7. Further challenges
Our model provides a qualitative understanding of several phenomena that
are not normally analysed within preon models, nor within the standard
model. It can hence serve as a basis for a deeper understanding of the
quantitative success of the standard model.
However, many problems remain to be solved, and I will finish by listing
some of them below.
(i) The model lacks a dynamical basis, which means that masses cannot
yet be explained, the exact preon wave functions cannot be calculated, and
the forces that keep leptons and quarks together are not understood. In
this respect we are worse off than the original quark model, which at least
rested on a phenomenologically successful mass formula for baryons.
(ii) There is no particular reason why quarks would be as fundamental
as leptons in our model, or even exist as particles, since there is no obvious
hyper-QCD theory that would make quarks “hyper-colour neutral”, like
leptons. The fundamental status of quarks must therefore be due to some
more intricate dynamics.
(iii) It is not yet clear to us if all phenomenologically successful aspects
of the electroweak theory can be explained by preons, not to mention CP
violation. A lot of work remains to be done, maybe of the order of the total
work so far devoted to the standard model, i.e., a few thousand man-years!
(iv) The hints of a slightly broken preon flavour conservation reminds
so much of the quark model that the mind goes to yet more preons, even
unstable ones and in families, which would again call for a model with
fewer, and more basic constituents, i.e., pre-preons.
11
12. Acknowledgements
I would like to thank the Organisers of this meeting, and the audience,
for providing a wonderful intellectual atmosphere, and a breathtaking en-
vironment. We acknowledge helpful and inspiring remarks by P. Arve and
D. Enstr¨m, illuminating correspondences with H. Fritzsch, A. Davidson,
o
E. Ma and N. Tracas, as well as valuable experimental information from
G. Bellettini, R. Partridge and G. VanDalen. This project is supported by
the European Commission under contract CHRX-CT94-0450, within the
network “The Fundamental Structure of Matter”.
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a
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