This document discusses two projects related to the Upsilon meson. The first estimates the systematic uncertainty associated with Upsilon polarization measurements at the LHC due to detector acceptance effects. The second analyzes Upsilon yields from STAR data at RHIC to compare to recent CMS findings of a correlation between Upsilon production and event activity measures. While STAR sees a less pronounced correlation possibly due to lower statistics, both detectors aim to better understand Upsilon properties to reveal characteristics of the quark-gluon plasma.
Future ground arrays for ultrahigh-energy cosmic rays: recent updates and per...Toshihiro FUJII
The document summarizes recent updates on future ground-based arrays for detecting ultra-high energy cosmic rays. It discusses key findings from UHECR observations including the energy spectrum measured by the Telescope Array and Pierre Auger Observatory experiments. There is good agreement between the two experiments within systematic uncertainties, though the second break point in the energy spectrum occurs at a slightly higher energy for TA. It also summarizes mass composition results from Xmax distributions, finding the data is best described by a mix of light and intermediate mass nuclei. No significant photons or neutrinos have been detected at the highest energies that would be expected from the GZK effect.
This is the presentation I gave when defending my Ph.D thesis at SLAC. The title of my defense was "Neutron Star Powered Nebulae: a New View on Pulsar Wind Nebulae with the Fermi Gamma-ray Space Telescope".
Artigo que descreve o trabalho feito com o Chandra nos aglomerados de galáxias de Perseus e Virgo sobre a descoberta de uma turbulência cósmica que impede a formação de novas estrelas.
This document discusses using density functional theory with different basis sets (Gaussian, plane waves, numerical) to calculate exchange coupling constants in transition metal complexes. It compares the accuracy and reliability of these approaches by calculating exchange coupling constants and spin distributions for three test complexes. The plane wave and numerical basis set approaches are found to be accurate alternatives to the more established Gaussian basis functions for calculating these properties, while also allowing for larger system sizes to be studied. Pseudopotentials are also found to not significantly affect the calculation of exchange coupling constants.
Adding a Shift term to solve the 4/3 problem in classical electrodinamicsSergio Prats
This work shows that for a charged spherical surface moving at slow speed, 푣 ≪ 푐, the 4/3
discrepancy between the electromagnetic (EM) mass calculated from (a) the field’s energy and
(b) the field’s momentum is solved by taking into account the exchange of energy between the
field and the charge on the surface of the sphere, while this interaction does not change the
overall field energy, it shifts the energy in the direction opposed to the sphere velocity. If we
take the electromagnetic mass as the one obtained from the electrostatic energy, this shift
adds a new term to the field velocity that makes it to move with the same velocity than the
charge, hence compensating the excess of momentum in the EM field.
Constraining photon dispersion relation from observations of the Vela pulsar ...Mathieu Chrétien
talk at ICRC 2015.
Some approaches to Quantum Gravity (QG) predict a modification of photon dispersion relations
due to a breaking of Lorentz invariance. The effect is expected to affect photons near an effective
QG energy scale. This scale has been constrained by observing gamma rays emitted from variable
astrophysical sources such as gamma-ray bursts and flaring active galactic nuclei. Pulsars exhibit
a periodic emission of possibly ms time scale. In 2014, the H.E.S.S. experiment reported the
detection down to 20 GeV of gamma rays from the Vela pulsar having a periodicity of 89 ms.
Using a likelihood analysis, calibrated with a dedicated Monte-Carlo procedure, we obtain the
first limit on QG energy scale with the Vela pulsar. In this paper, the method and calibration
procedure in use will be described and the results will be discussed.
link to proceeding: http://arxiv.org/abs/1509.03545
The Equation Based on the Rotational and Orbital Motion of the PlanetsIJERA Editor
Equations of dependence of rotational and orbital motions of planets are given, their rotation angles are calculated. Wave principles of direct and reverse rotation of planets are established. The established dependencies are demonstrated at different scale levels of structural interactions, in biosystems as well. The accuracy of calculations corresponds to the accuracy of experimental data
Future ground arrays for ultrahigh-energy cosmic rays: recent updates and per...Toshihiro FUJII
The document summarizes recent updates on future ground-based arrays for detecting ultra-high energy cosmic rays. It discusses key findings from UHECR observations including the energy spectrum measured by the Telescope Array and Pierre Auger Observatory experiments. There is good agreement between the two experiments within systematic uncertainties, though the second break point in the energy spectrum occurs at a slightly higher energy for TA. It also summarizes mass composition results from Xmax distributions, finding the data is best described by a mix of light and intermediate mass nuclei. No significant photons or neutrinos have been detected at the highest energies that would be expected from the GZK effect.
This is the presentation I gave when defending my Ph.D thesis at SLAC. The title of my defense was "Neutron Star Powered Nebulae: a New View on Pulsar Wind Nebulae with the Fermi Gamma-ray Space Telescope".
Artigo que descreve o trabalho feito com o Chandra nos aglomerados de galáxias de Perseus e Virgo sobre a descoberta de uma turbulência cósmica que impede a formação de novas estrelas.
This document discusses using density functional theory with different basis sets (Gaussian, plane waves, numerical) to calculate exchange coupling constants in transition metal complexes. It compares the accuracy and reliability of these approaches by calculating exchange coupling constants and spin distributions for three test complexes. The plane wave and numerical basis set approaches are found to be accurate alternatives to the more established Gaussian basis functions for calculating these properties, while also allowing for larger system sizes to be studied. Pseudopotentials are also found to not significantly affect the calculation of exchange coupling constants.
Adding a Shift term to solve the 4/3 problem in classical electrodinamicsSergio Prats
This work shows that for a charged spherical surface moving at slow speed, 푣 ≪ 푐, the 4/3
discrepancy between the electromagnetic (EM) mass calculated from (a) the field’s energy and
(b) the field’s momentum is solved by taking into account the exchange of energy between the
field and the charge on the surface of the sphere, while this interaction does not change the
overall field energy, it shifts the energy in the direction opposed to the sphere velocity. If we
take the electromagnetic mass as the one obtained from the electrostatic energy, this shift
adds a new term to the field velocity that makes it to move with the same velocity than the
charge, hence compensating the excess of momentum in the EM field.
Constraining photon dispersion relation from observations of the Vela pulsar ...Mathieu Chrétien
talk at ICRC 2015.
Some approaches to Quantum Gravity (QG) predict a modification of photon dispersion relations
due to a breaking of Lorentz invariance. The effect is expected to affect photons near an effective
QG energy scale. This scale has been constrained by observing gamma rays emitted from variable
astrophysical sources such as gamma-ray bursts and flaring active galactic nuclei. Pulsars exhibit
a periodic emission of possibly ms time scale. In 2014, the H.E.S.S. experiment reported the
detection down to 20 GeV of gamma rays from the Vela pulsar having a periodicity of 89 ms.
Using a likelihood analysis, calibrated with a dedicated Monte-Carlo procedure, we obtain the
first limit on QG energy scale with the Vela pulsar. In this paper, the method and calibration
procedure in use will be described and the results will be discussed.
link to proceeding: http://arxiv.org/abs/1509.03545
The Equation Based on the Rotational and Orbital Motion of the PlanetsIJERA Editor
Equations of dependence of rotational and orbital motions of planets are given, their rotation angles are calculated. Wave principles of direct and reverse rotation of planets are established. The established dependencies are demonstrated at different scale levels of structural interactions, in biosystems as well. The accuracy of calculations corresponds to the accuracy of experimental data
The team detected signals from the Magellanic Stream using the 4.5m radio telescope at Leuschner Observatory. Images of the observed region in galactic coordinates showed high-velocity gases from -100 to -350 km/s, consistent with the Magellanic Stream. A velocity map matched previous studies, and higher intensities near the galactic pole aligned with expectations. Issues with intensity calibration and single polarization data collection impacted accuracy but detection of the stream was achieved.
Calculation method based on experimental data to estimate sunlight intensity falling on the solar
collector has been established. The technique is to evaluate the heat power using the specific heat formula.
Light intensity from 3 different light sources has been studied; the results gained by the method were compared
against other results directly measured using intensity meter, and both results showed good agreement. The
method shows powerful tools, which can estimate the light intensity in the lack of intensity meter. Although, the
specific heat formula has been used previously for a estimating different heat transfer purpose, however, this
method has advantage by providing approximation results in simple way, and it use to determine the
performance of flat panel solar thermal systems under variable solar flux.
Thermal Radiation-I - Basic properties and Lawstmuliya
This file contains slides on RADIATION-I: Basic Properties and Laws.
The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India, during Sept. – Dec. 2010.
Contents: Introduction – Applications – Electromagnetic spectrum – Properties and definitions – Laws of black body radiation – Planck’s Law – Wein’s displacement law – Stefan Boltzmann Law – Radiation from a wave band – Emissivity – Kirchoff’s Law- Problems
This paper discusses trajectories to transfer a spacecraft between the Lagrangian points of the Sun-Earth system and the primaries. The planar circular restricted three-body problem is used to model the Sun-Earth system. Lamaître regularization is applied to avoid singularities during numerical integration of the Lambert's three-body problem. Families of transfer orbits between the Lagrangian points and primaries are presented, parameterized by transfer time. Results include plots of the energy and initial flight path angle versus transfer time, as well as example trajectories. Comparisons are made to transfers in the Earth-Moon system.
1) Gravitational and electric fields can be described by their field strength, which is defined as the force exerted per unit mass or charge.
2) Gravitational field strength is calculated using Newton's law of universal gravitation, while electric field strength uses Coulomb's law.
3) The electric potential at a point is defined as the work required to move a unit charge from infinity to that point, and equipotentials are surfaces or lines of constant potential.
This document discusses the energy characteristics of interactions between particles and systems. It introduces the concept of a spatial-energy parameter (P-parameter) to describe interactions. The key points are:
1) Interactions along a potential gradient (positive work) calculate the resulting potential energy by adding reciprocals of subsystem energies. Interactions against the gradient (negative work) add subsystem masses and energies algebraically.
2) P-parameter is proposed to quantify the energy of atom valence orbitals based on electron orbital energies and radii. For similar systems, P-parameters are added algebraically.
3) P-parameter is analogous to the quantum mechanical wave function and has wave properties. It provides a way to materialize
Evidence for the charge-excess contribution in air shower radio emission obse...Ahmed Ammar Rebai PhD
The following paper I co-authored is now online on slideshare! I participated in the Codalema Experiment operations and data analysis since July 2009 until February 2014.
Context. Observation of the charge-excess mechanism in the emission of the electric field from cosmic ray air showers.
Aims. It is shown that the signature of the charge-excess mechanism is present in the CODALEMA data
Methods. The data exhibits a shift in the ground position in the shower cores seen from the radio data and the particle
data. This shift is explained when using a simulation code taking into account or not the charge-excess mechanism.
Results. Evidence for the charge-excess in the atmospheric shower has been found via the electric field emitted by the
secondary particle and detected by the CODALEMA experiment.
Conclusions. The systematic shift between the shower core estimation using separately the particle array data and
the radio array data of the CODALEMA experiment is discussed. Using the simulation code SELFAS2 we show that
the consideration of the charge-excess contribution in the total radio emission of air showers generates a shift of the
apparent ground radio core along the east-west axis in good agreement with the observations. This radio core shift is
then characterized for the CODALEMA setup and compared with the data. The observation of this systematic shift
can be considered as an experimental signature of the charge excess contribution.
1) The document discusses a model for constraining the evolution of supermassive black holes through solving the continuity equation, using observational data on quasar luminosity functions and scaling relations between black hole mass and galaxy properties.
2) The model assumes parametric forms for the duty cycle of active black holes, Eddington ratio distribution as a function of redshift, and solves the continuity equation backwards in time using the local black hole mass function as a boundary condition.
3) The best-fit model reproduces observational data on luminosity functions and mass functions of active black holes, and implies an anti-hierarchical growth of black holes with cosmic downsizing. The model can constrain the radiative efficiency and favors values around 5-10
Fundamental Concepts on Electromagnetic TheoryAL- AMIN
The document summarizes key concepts from a presentation on electromagnetic theory. It discusses different types of fields, including scalar and vector fields. It also covers gradient, divergence, curl, coordinate systems, static electric and magnetic fields, Maxwell's equations, and other fundamental electromagnetic concepts. Multiple students contributed sections on topics including Coulomb's law, Biot-Savart law, Lorentz force, and Maxwell's equations in differential, integral and harmonic forms.
This paper develops a mathematical model to analyze the kinetic energy present in a stable bathtub vortex. It uses Burgers' vortex model to describe the azimuthal velocity field and derives an expression for kinetic energy by integrating over the cylindrical tank volume. The model shows that kinetic energy increases linearly with tank height and Reynolds number. It also indicates that a turbine placed at 20% of the tank radius would optimally capture energy, as this corresponds to the peak kinetic energy region away from the vortex core. The paper concludes by discussing opportunities to improve the model by incorporating more realistic fluid effects and accounting for turbine properties.
1) The document reports on a computational study of the chemical mechanism and kinetics of the ocimene ozonolysis reaction in the atmosphere. Rate constants and lifetimes of reaction intermediates were calculated.
2) RRKM theory and canonical variational transition state theory (CVTST) were used to derive kinetic equations and calculate microcanonical rate constants for the elementary reaction steps.
3) Results show ocimene has a short lifetime of 86 minutes, while some intermediates have longer lifetimes of days. The kinetic data provides insight into secondary organic aerosol formation from biogenic monoterpene oxidation.
This document provides information and homework problems related to electromagnetic theory and electromagnetic homework help. It includes 6 problems about Maxwell's stress tensor, forces on dielectric materials and conductors due to electric and magnetic fields, energy balance in conductors, the memory function, and using Kramers-Kronig relations to obtain sum rules and properties of the dielectric function. Students are directed to a website and contact information for assistance with electromagnetic assignment help.
This document provides instructions for analyzing the distribution of earthquakes based on magnitude, time, and location with a focus on clustering characteristics. It discusses Gutenberg-Richter's law which describes the relationship between earthquake magnitude and frequency. It also examines methods for calculating the b-value coefficient and considers the effects of aftershocks on magnitude distributions. The document proposes a model relating the magnitude distributions of main shocks, aftershocks, and all earthquakes based on b-values and the degree of aftershock activity.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Some possible interpretations from data of the CODALEMA experimentAhmed Ammar Rebai PhD
The purpose of the CODALEMA experiment, installed at the Nan\c{c}ay Radio Observatory (France), is to study the radio-detection of ultra-high energy cosmic rays in the energy range of 10^{16}-10^{18} eV. Distributed over an area of 0.25 km^2, the original device uses in coincidence an array of particle detectors and an array of short antennas, with a centralized acquisition. A new analysis of the observable in energy for radio is presented from this system, taking into account the geomagnetic effect. Since 2011, a new array of radio-detectors, consisting of 60 stand-alone and self-triggered stations, is being deployed over an area of 1.5 km^2 around the initial configuration. This new development leads to specific constraints to be discussed in term of recognition of cosmic rays and in term of analysis of wave-front.
1) The document provides an overview of the contents of Part II of a slideshow on modern physics, which covers topics such as charge and current densities, electromagnetic induction, Maxwell's equations, special relativity, tensors, blackbody radiation, photons, electrons, scattering problems, and waves.
2) It aims to provide a brief yet modern review of foundational concepts in electromagnetism and set the stage for introducing special relativity, quantum mechanics, and matter waves for undergraduate students.
3) The overview highlights that succeeding chapters will develop tensor formulations of electromagnetism and special relativity from first principles before discussing applications like blackbody radiation and early quantum models.
The document discusses three equations commonly used in fluid mechanics - the mass, Bernoulli, and energy equations. It provides an overview of the conservation of mass principle and defines relevant terms like mass flow rate. It then discusses various forms of mechanical energy and energy conversion efficiencies. Finally, it outlines how the Bernoulli equation is derived from Newton's second law and how the energy equation is developed and applied to fluid mechanics problems.
Thermal Radiation-II- View factors and Radiation energy exchange between blac...tmuliya
This file contains slides on THERMAL RADIATION-II: View factors and Radiation energy exchange between black bodies.
The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India, during Sept. – Dec. 2010.
Contents: View factor – general relations – radiation energy exchange between black bodies – properties of view factor and view factor algebra – view factor formulas and graphs – Problems
Sir Cyril Hinshelwood and Nikolaevich received the 1956 Nobel Prize in Chemistry for their research on chemical reaction mechanisms. Hinshelwood modified Lindemann's explanation for unimolecular reactions by proposing that energized molecules (A*) may store energy in various molecular bonds and vibrational degrees of freedom, rather than immediately reacting. This statistical distribution of energy among s degrees of freedom leads to a modified rate constant expression containing an additional term of 1/(s-1) that can account for much higher observed reaction rates. However, Hinshelwood's theory does not fully explain some experimental observations such as the temperature dependence of rate constants and nonlinear plots of 1/k1 versus concentration.
I am Irene M. I am an Electromagnetism Assignment Expert at eduassignmenthelp.com. I hold a Ph.D. in Electromagnetism, from California, USA. I have been helping students with their homework for the past 8 years. I solve assignments related to Electromagnetism.
Visit eduassignmenthelp.com or email info@eduassignmenthelp.com.
You can also call on +1 678 648 4277 for any assistance with Electromagnetism Assignments.
The island algorithm is a photon clusterization method used in the sPHENIX detector upgrade. It identifies photon clusters by starting from energy towers above a threshold and grouping adjacent towers. For single particle simulations, it closely reconstructs particle energies. It performs better than a simple 5x5 clusterizer which can overestimate energies. While it reliably clusters electrons, photons and pions, more testing is needed with complex events before full implementation.
This document describes a lattice QCD computation of the proton isovector scalar charge (gs) at two unphysical quark masses. Jackknife statistics and all-mode averaging techniques are used to calculate correlation functions from Monte Carlo simulations, which are then fitted and extrapolated to obtain gs at the physical quark mass. Results show the unrenormalized values of gs computed at quark masses of 0.0042 and 0.0015, with the goal of constraining gs through precise theoretical calculations needed to interpret experimental measurements.
The team detected signals from the Magellanic Stream using the 4.5m radio telescope at Leuschner Observatory. Images of the observed region in galactic coordinates showed high-velocity gases from -100 to -350 km/s, consistent with the Magellanic Stream. A velocity map matched previous studies, and higher intensities near the galactic pole aligned with expectations. Issues with intensity calibration and single polarization data collection impacted accuracy but detection of the stream was achieved.
Calculation method based on experimental data to estimate sunlight intensity falling on the solar
collector has been established. The technique is to evaluate the heat power using the specific heat formula.
Light intensity from 3 different light sources has been studied; the results gained by the method were compared
against other results directly measured using intensity meter, and both results showed good agreement. The
method shows powerful tools, which can estimate the light intensity in the lack of intensity meter. Although, the
specific heat formula has been used previously for a estimating different heat transfer purpose, however, this
method has advantage by providing approximation results in simple way, and it use to determine the
performance of flat panel solar thermal systems under variable solar flux.
Thermal Radiation-I - Basic properties and Lawstmuliya
This file contains slides on RADIATION-I: Basic Properties and Laws.
The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India, during Sept. – Dec. 2010.
Contents: Introduction – Applications – Electromagnetic spectrum – Properties and definitions – Laws of black body radiation – Planck’s Law – Wein’s displacement law – Stefan Boltzmann Law – Radiation from a wave band – Emissivity – Kirchoff’s Law- Problems
This paper discusses trajectories to transfer a spacecraft between the Lagrangian points of the Sun-Earth system and the primaries. The planar circular restricted three-body problem is used to model the Sun-Earth system. Lamaître regularization is applied to avoid singularities during numerical integration of the Lambert's three-body problem. Families of transfer orbits between the Lagrangian points and primaries are presented, parameterized by transfer time. Results include plots of the energy and initial flight path angle versus transfer time, as well as example trajectories. Comparisons are made to transfers in the Earth-Moon system.
1) Gravitational and electric fields can be described by their field strength, which is defined as the force exerted per unit mass or charge.
2) Gravitational field strength is calculated using Newton's law of universal gravitation, while electric field strength uses Coulomb's law.
3) The electric potential at a point is defined as the work required to move a unit charge from infinity to that point, and equipotentials are surfaces or lines of constant potential.
This document discusses the energy characteristics of interactions between particles and systems. It introduces the concept of a spatial-energy parameter (P-parameter) to describe interactions. The key points are:
1) Interactions along a potential gradient (positive work) calculate the resulting potential energy by adding reciprocals of subsystem energies. Interactions against the gradient (negative work) add subsystem masses and energies algebraically.
2) P-parameter is proposed to quantify the energy of atom valence orbitals based on electron orbital energies and radii. For similar systems, P-parameters are added algebraically.
3) P-parameter is analogous to the quantum mechanical wave function and has wave properties. It provides a way to materialize
Evidence for the charge-excess contribution in air shower radio emission obse...Ahmed Ammar Rebai PhD
The following paper I co-authored is now online on slideshare! I participated in the Codalema Experiment operations and data analysis since July 2009 until February 2014.
Context. Observation of the charge-excess mechanism in the emission of the electric field from cosmic ray air showers.
Aims. It is shown that the signature of the charge-excess mechanism is present in the CODALEMA data
Methods. The data exhibits a shift in the ground position in the shower cores seen from the radio data and the particle
data. This shift is explained when using a simulation code taking into account or not the charge-excess mechanism.
Results. Evidence for the charge-excess in the atmospheric shower has been found via the electric field emitted by the
secondary particle and detected by the CODALEMA experiment.
Conclusions. The systematic shift between the shower core estimation using separately the particle array data and
the radio array data of the CODALEMA experiment is discussed. Using the simulation code SELFAS2 we show that
the consideration of the charge-excess contribution in the total radio emission of air showers generates a shift of the
apparent ground radio core along the east-west axis in good agreement with the observations. This radio core shift is
then characterized for the CODALEMA setup and compared with the data. The observation of this systematic shift
can be considered as an experimental signature of the charge excess contribution.
1) The document discusses a model for constraining the evolution of supermassive black holes through solving the continuity equation, using observational data on quasar luminosity functions and scaling relations between black hole mass and galaxy properties.
2) The model assumes parametric forms for the duty cycle of active black holes, Eddington ratio distribution as a function of redshift, and solves the continuity equation backwards in time using the local black hole mass function as a boundary condition.
3) The best-fit model reproduces observational data on luminosity functions and mass functions of active black holes, and implies an anti-hierarchical growth of black holes with cosmic downsizing. The model can constrain the radiative efficiency and favors values around 5-10
Fundamental Concepts on Electromagnetic TheoryAL- AMIN
The document summarizes key concepts from a presentation on electromagnetic theory. It discusses different types of fields, including scalar and vector fields. It also covers gradient, divergence, curl, coordinate systems, static electric and magnetic fields, Maxwell's equations, and other fundamental electromagnetic concepts. Multiple students contributed sections on topics including Coulomb's law, Biot-Savart law, Lorentz force, and Maxwell's equations in differential, integral and harmonic forms.
This paper develops a mathematical model to analyze the kinetic energy present in a stable bathtub vortex. It uses Burgers' vortex model to describe the azimuthal velocity field and derives an expression for kinetic energy by integrating over the cylindrical tank volume. The model shows that kinetic energy increases linearly with tank height and Reynolds number. It also indicates that a turbine placed at 20% of the tank radius would optimally capture energy, as this corresponds to the peak kinetic energy region away from the vortex core. The paper concludes by discussing opportunities to improve the model by incorporating more realistic fluid effects and accounting for turbine properties.
1) The document reports on a computational study of the chemical mechanism and kinetics of the ocimene ozonolysis reaction in the atmosphere. Rate constants and lifetimes of reaction intermediates were calculated.
2) RRKM theory and canonical variational transition state theory (CVTST) were used to derive kinetic equations and calculate microcanonical rate constants for the elementary reaction steps.
3) Results show ocimene has a short lifetime of 86 minutes, while some intermediates have longer lifetimes of days. The kinetic data provides insight into secondary organic aerosol formation from biogenic monoterpene oxidation.
This document provides information and homework problems related to electromagnetic theory and electromagnetic homework help. It includes 6 problems about Maxwell's stress tensor, forces on dielectric materials and conductors due to electric and magnetic fields, energy balance in conductors, the memory function, and using Kramers-Kronig relations to obtain sum rules and properties of the dielectric function. Students are directed to a website and contact information for assistance with electromagnetic assignment help.
This document provides instructions for analyzing the distribution of earthquakes based on magnitude, time, and location with a focus on clustering characteristics. It discusses Gutenberg-Richter's law which describes the relationship between earthquake magnitude and frequency. It also examines methods for calculating the b-value coefficient and considers the effects of aftershocks on magnitude distributions. The document proposes a model relating the magnitude distributions of main shocks, aftershocks, and all earthquakes based on b-values and the degree of aftershock activity.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Some possible interpretations from data of the CODALEMA experimentAhmed Ammar Rebai PhD
The purpose of the CODALEMA experiment, installed at the Nan\c{c}ay Radio Observatory (France), is to study the radio-detection of ultra-high energy cosmic rays in the energy range of 10^{16}-10^{18} eV. Distributed over an area of 0.25 km^2, the original device uses in coincidence an array of particle detectors and an array of short antennas, with a centralized acquisition. A new analysis of the observable in energy for radio is presented from this system, taking into account the geomagnetic effect. Since 2011, a new array of radio-detectors, consisting of 60 stand-alone and self-triggered stations, is being deployed over an area of 1.5 km^2 around the initial configuration. This new development leads to specific constraints to be discussed in term of recognition of cosmic rays and in term of analysis of wave-front.
1) The document provides an overview of the contents of Part II of a slideshow on modern physics, which covers topics such as charge and current densities, electromagnetic induction, Maxwell's equations, special relativity, tensors, blackbody radiation, photons, electrons, scattering problems, and waves.
2) It aims to provide a brief yet modern review of foundational concepts in electromagnetism and set the stage for introducing special relativity, quantum mechanics, and matter waves for undergraduate students.
3) The overview highlights that succeeding chapters will develop tensor formulations of electromagnetism and special relativity from first principles before discussing applications like blackbody radiation and early quantum models.
The document discusses three equations commonly used in fluid mechanics - the mass, Bernoulli, and energy equations. It provides an overview of the conservation of mass principle and defines relevant terms like mass flow rate. It then discusses various forms of mechanical energy and energy conversion efficiencies. Finally, it outlines how the Bernoulli equation is derived from Newton's second law and how the energy equation is developed and applied to fluid mechanics problems.
Thermal Radiation-II- View factors and Radiation energy exchange between blac...tmuliya
This file contains slides on THERMAL RADIATION-II: View factors and Radiation energy exchange between black bodies.
The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India, during Sept. – Dec. 2010.
Contents: View factor – general relations – radiation energy exchange between black bodies – properties of view factor and view factor algebra – view factor formulas and graphs – Problems
Sir Cyril Hinshelwood and Nikolaevich received the 1956 Nobel Prize in Chemistry for their research on chemical reaction mechanisms. Hinshelwood modified Lindemann's explanation for unimolecular reactions by proposing that energized molecules (A*) may store energy in various molecular bonds and vibrational degrees of freedom, rather than immediately reacting. This statistical distribution of energy among s degrees of freedom leads to a modified rate constant expression containing an additional term of 1/(s-1) that can account for much higher observed reaction rates. However, Hinshelwood's theory does not fully explain some experimental observations such as the temperature dependence of rate constants and nonlinear plots of 1/k1 versus concentration.
I am Irene M. I am an Electromagnetism Assignment Expert at eduassignmenthelp.com. I hold a Ph.D. in Electromagnetism, from California, USA. I have been helping students with their homework for the past 8 years. I solve assignments related to Electromagnetism.
Visit eduassignmenthelp.com or email info@eduassignmenthelp.com.
You can also call on +1 678 648 4277 for any assistance with Electromagnetism Assignments.
The island algorithm is a photon clusterization method used in the sPHENIX detector upgrade. It identifies photon clusters by starting from energy towers above a threshold and grouping adjacent towers. For single particle simulations, it closely reconstructs particle energies. It performs better than a simple 5x5 clusterizer which can overestimate energies. While it reliably clusters electrons, photons and pions, more testing is needed with complex events before full implementation.
This document describes a lattice QCD computation of the proton isovector scalar charge (gs) at two unphysical quark masses. Jackknife statistics and all-mode averaging techniques are used to calculate correlation functions from Monte Carlo simulations, which are then fitted and extrapolated to obtain gs at the physical quark mass. Results show the unrenormalized values of gs computed at quark masses of 0.0042 and 0.0015, with the goal of constraining gs through precise theoretical calculations needed to interpret experimental measurements.
The document provides an overview of the SPHENIX Clusterizer algorithm used at CMS. It describes the island algorithm which clusters calorimeter towers starting from the highest energy seed tower and moving in φ and η directions until an energy rise or hole is found. Simple checks are performed using single particle events to evaluate the number and energy of clusters compared to the generated particle properties. Further work is planned to characterize shower shapes and evaluate performance on more complex events.
This document summarizes a research project that involves building a toy model of particle collisions using C++ and ROOT. The model simulates collisions by sampling probability distributions measured in real collisions. It generates particles and assigns them properties like momentum and angle. It also models physical processes like jet production and elliptic flow. The goal is to study how properties of particles like jets are affected by a quark-gluon plasma and vice versa. The model allows tuning parameters to learn about collision interactions and switch physics processes on or off.
This document presents results from a lattice QCD calculation of the proton isovector scalar charge (gs) at two light quark masses. The calculation uses domain-wall fermions and Iwasaki gauge actions on a 323x64 lattice with a spacing of 0.144 fm. Ratios of three-point to two-point correlation functions are formed and fit to a plateau to extract gs. Values of gs are obtained for quark masses of 0.0042 and 0.001, and all-mode averaging is used for the lighter mass. Chiral perturbation theory will be used to extrapolate gs to the physical quark mass. Preliminary results for gs at the unphysical quark masses are reported in lattice units.
This document provides an overview of a toy model for simulating particle collisions. It describes sampling particle data from experimental measurements to generate events. A jet finding algorithm is used to cluster particles into jets using FastJet. The current status indicates particle generation works as expected but jet finding results appear buggy. Next steps involve analyzing jet distributions and performance of the jet finder on simulated events without embedded jets. Possible extensions include jet fragmentation.
The document proposes a test bench to conduct R&D for an Event Plane and Centrality Detector. Specifically, it will test different detector technologies including scintillator tiles with various pad geometries coupled to silicon photomultipliers. Cosmic ray and electron beam measurements are planned to characterize signal efficiency and timing resolution for different detector configurations. The goals are to optimize pad geometry, understand signal discrimination capabilities, and achieve the best timing resolution.
This document summarizes recent results from the STAR experiment regarding correlations and fluctuations in heavy ion collisions at RHIC. It discusses measurements of elliptic and directed flow that provide evidence for local equilibration and pressure gradients in the quark-gluon plasma. HBT interferometry measurements indicate a source elongated perpendicular to the reaction plane, consistent with initial collision geometry. Charge-dependent number correlations reveal modified hadronization in the quark-gluon plasma compared to pp collisions, suggesting local charge conservation effects during hadronization. Overall, the results provide insights into the equilibration and relevant degrees of freedom in the quark-gluon plasma.
Laser Pulsing in Linear Compton ScatteringTodd Hodges
This document summarizes a method for calculating the energy spectrum of radiation produced in linear Compton scattering, accounting for the pulsed structure of the incident laser beam. The method involves performing a Lorentz transformation of the Klein-Nishina scattering cross section to calculate the emission from individual electrons in an electron beam, and then summing over all electrons to obtain the total energy spectrum. This approach allows for accurate modeling of effects of electron beam energy spread and emittance. The method is then applied to predict the photon spectrum from a proposed compact inverse Compton scattering x-ray source at Old Dominion University.
This document summarizes a study on the structure and thermodynamics of colloid solutions interacting through Yukawa or Lu-Marlow potentials. The researchers used an expression described by Lu and Marlow that accounts for finite particle size. They calculated structure factors using a variational method based on the Gibbs-Bogoliubov inequality. The theoretical structure factors obtained were found to be in good agreement with experimental data, justifying the interest in the Lu-Marlow potential. They also used a reference system of hard spheres and the variational method to estimate thermodynamic properties of the colloid solutions.
This document proposes a new method to test the isotropy of ultrahigh energy cosmic ray arrival directions. The method analyzes how cosmic rays cluster together into groups as the maximum angular separation between events is increased. It characterizes the clustering process through various observables like the number and sizes of clusters. The method is applied to real data from the Pierre Auger Observatory. The strongest signal of anisotropy is found for events above 56.74 EeV with an angular scale of 4 degrees, rejecting isotropy at nearly 90% confidence level.
Multi-polarization reconstruction from compact polarimetry based on modified ...yinjj07
The document describes an improved algorithm for reconstructing multi-polarization information from compact polarimetry (CP) measurements. It proposes modifying the traditional four-component scattering decomposition model by using a new volume scattering model. This allows the decomposed helix scattering component to be used to account for non-reflection symmetry in CP data. It then develops an average relationship between co-polarized and cross-polarized channels based on the scattering powers and mechanisms. Experimental data demonstrates the effectiveness of the proposed reconstruction method.
41 Limits on Light-Speed Anisotropies from Compton Scattering of High-Energy ...Cristian Randieri PhD
Limits on Light-Speed Anisotropies from Compton Scattering of High-Energy Electrons -The American Physical Society, Physical Review Letters, June 2010, Vol. 104, N. 24, pp. 241601-1-241601-5, ISSN: 0031-9007, doi: 10.1103/PhysRevLett.104.241601
di J. P. Bocquet, D. Moricciani, V. Bellini, M. Beretta, L. Casano, A. D'Angelo, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, V. G. Gurzadyan, A. Kashin, S. Knyazyan, A. Lapik, R. Lehnert, P. Levi Sandri, A. Lleres, F. Mammoliti, G. Mandaglio, M. Manganaro, A. Margarian, S. Mehrabyan, R. Messi, V. Nedorezov, C. Perrin, C. Randieri, D. Rebreyend, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna (2010)
Abstract
The possibility of anisotropies in the speed of light relative to the limiting speed of electrons is considered. The absence of sidereal variations in the energy of Compton-edge photons at the ESRF's GRAAL facility constrains such anisotropies representing the first non-threshold collision-kinematics study of Lorentz violation. When interpreted within the minimal Standard-Model Extension, this result yields the two-sided limit of 1.6 x 10^{-14} at 95% confidence level on a combination of the parity-violating photon and electron coefficients kappa_{o+} and c. This new constraint provides an improvement over previous bounds by one order of magnitude.
This document discusses a study investigating the dependence of theoretical results for two-photon double ionization of H2 molecules on the relative orientation of the linear laser polarization and the molecular axis, as well as the length of femtosecond laser pulses. It finds that for perpendicular orientation, the effect of pulse duration is negligible near a photon energy of 30 eV, unlike for parallel orientation where resonance effects are observed. It also finds general agreement with other theoretical work except near 30 eV, where other studies predict cross sections about twice as large. The results are important benchmarks for understanding electron correlation in molecules driven by ultrashort laser pulses.
This document numerically analyzes the wave function of atoms under the combined effects of an optical lattice trapping potential and a harmonic oscillator potential, as used in Bose-Einstein condensation experiments. It employs the Crank-Nicolson scheme to solve the Gross-Pitaevskii equation. The results show that the wave function distribution responds to parameters like the trapping frequencies ratio, optical lattice intensity, chemical potential, and energy. Careful adjustment of the time step and grid spacing is needed to satisfy conservation of norms and energy as required by the physical system. Distributions of the overlapping potentials for different q-factors are presented.
This document contains study materials for aeronautical engineering students. It covers several topics in fluid dynamics including the continuity equation, momentum equation, energy equation, and concepts like irrotational flow, streamlines, and vorticity. It also discusses flow measurement devices like venturi meters and orifice meters. Several key equations are derived from first principles including the continuity equation, momentum equation, and energy equation.
This document discusses computer simulations of the structure and thermodynamics of colloidal solutions interacting through Yukawa or Lu-Marlow potentials. It presents:
1) A new attractive potential proposed by Lu and Marlow that takes into account particle size and is proportional to the inverse sixth power of distance for large separations.
2) Use of this potential and a repulsive electrostatic potential in a variational method to calculate theoretical structure factors, finding good agreement with experimental data.
3) Choice of hard spheres as a reference system and use of the Gibbs-Bogoliubov inequality to obtain an upper bound for the free energy of the colloidal system.
This document presents a theoretical model for simulating cyclic voltammetry experiments under conditions where migration effects are significant due to low supporting electrolyte concentrations. The model involves numerically solving the coupled Nernst-Planck and Poisson equations to determine concentration and potential profiles throughout the solution. Parameters such as electrode size, scan rate, diffusion coefficients, and supporting electrolyte concentration are varied to examine their effects on the voltammogram shape. Experimental cyclic voltammetry data for a ruthenium complex with varying amounts of KCl supporting electrolyte is also presented for comparison to the model. The model is shown to be applicable when the ratio of supporting electrolyte to analyte concentration exceeds 30.
1) DUNE aims to resolve the matter-antimatter asymmetry by searching for neutron-antineutron oscillations, a baryon number violating process.
2) Simulations of atmospheric neutrino backgrounds that could mimic the signal are underway using GENIE to determine the viability of detecting oscillations above background levels.
3) If viable, the analysis will consider effects of cosmogenic muons and fast neutrons, with generators for neutron-antineutron interactions in argon under construction.
48 Measurement of the Σ beam asymmetry for the ω photo-production off the pro...Cristian Randieri PhD
Measurement of the Σ beam asymmetry for the ω photo-production off the proton and the neutron at GRAAL - June 2013
di V. Vegna, A. D'Angelo, O. Bartalini, V. Bellini, J. P. Boquet, M. Capogni, L. E. Casano, M. Castoldi, F. Curciarello, V. De Leo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, A. Lapik, P. Levi Sandri, A. Lleres, F. Mammoliti, G. Mandaglio, M. Manganaro, D. Moricciani, A. Mushkarenkov, V. Nedorezov, C. Randieri, D. Rebreyend, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, I. Zonta (2013)
Abstract
We report on new measurements of the beam asymmetry for ω photo-production on proton and neutron in Hydrogen and Deuterium targets from the GRAAL collaboration. The beam asymmetry values are extracted from the reaction threshold (E = 1.1 GeV in the free nucleon kinematics) up to 1.5 GeV of incoming photon energy. For the first time both the radiative and the three- pion decay channels are simultaneously investigated on the free proton. Results from the two decay channels are in agreement and provide important constraints for the determination of resonant state contributions to the ω production mechanism. First experimental results on the deuteron allow the extraction of the _ beam asymmetry on quasi-free nucleons. Comparison of the results for free and quasi-free kinematics on the proton shows a generally reasonable agreement, similar to the findings in pseudo-scalar meson photo-production reactions. For the first time measurements on quasi-free neutrons are available, showing that both the strength and the angular distributions of the beam asymmetry are sensibly different from the results on the proton target.
Results from telescope_array_experimentSérgio Sacani
The Telescope Array (TA) experiment studies ultrahigh energy cosmic rays using a hybrid detector consisting of a surface detector and three fluorescence detector stations. This paper reports three results from TA:
1) The cosmic ray spectrum measured by the surface detector shows an ankle feature and a 3.5 sigma suppression at the expected GZK cutoff energy, consistent with the HiRes experiment.
2) Measurement of the average shower maximum depth with the fluorescence detectors indicates a light composition, most likely protons.
3) A search for correlations between surface detector events and Active Galactic Nuclei found no significant correlations, consistent with results from HiRes.
This document provides an overview of nuclear magnetic resonance (NMR) spectroscopy. It discusses key concepts such as Larmor precession, spin-spin and spin-lattice relaxation, relative line intensities, and the quantum mechanical treatment of the AB spin system. The document is a seminar presentation that covers the basic principles and applications of NMR spectroscopy for structure determination of organic and inorganic compounds.
This document discusses the use of trapped atomic ions for quantum information processing and the creation of entangled states. It describes how ions can be trapped and laser cooled to suppress environmental perturbations and allow for coherent manipulation over long durations. Recent experiments have successfully generated entanglement between the internal states of pairs of trapped ions, implemented quantum logic gates like CNOT, and improved tools for high-precision measurement. Trapped ions provide a promising system for studying and applying concepts of quantum information processing.
This document summarizes the use of positron annihilation techniques to study semiconductors and lattice defects. Positrons emitted from radioactive nuclei can be used to probe vacancy-type defects in materials. When a positron encounters an electron, they annihilate and emit gamma rays. By analyzing properties of the gamma rays like energy, momentum, and timing, information can be gained about the defect where annihilation occurred, allowing quantification of defect types, concentrations, and charge states in semiconductors. Common positron annihilation techniques described include positron lifetime spectroscopy and Doppler broadening spectroscopy.
Quark Model Three Body Calculations for the Hypertriton Bound StateIOSR Journals
Hyperspherical three body calculations are performed to study and review the various properties of
the hypertriton bound state nucleus
3H in the quark model using -N potentials. In these calculations we study
the different effects of the -N potentials on the hypertriton bound states as well as the separation energy B. A
combination of realistic two body N-N potentials with various - N potentials are considered. Complete
symmetric and mixed symmetric wave functions are introduced. using the renormalized Numerov method. The
agreement between the calculated
3H binding energies and the available experimental data basically depends
on the type of the -N interactions used in the calculations. It was found that the -N potentials are the most
effective part in the hypertriton binding energy as well as the separation energy B where the -N potentials is
very effective to bound or unbound the
3H hyper nucleus
Pacs numbers: 21.30. + y, 21.10.+dr,27.20.+n
Role of Magnetic Reconnection in Coronal Heatingijtsrd
The outermost atmosphere of the Sun, called the corona, is some 200 times hotter than the surface of the Sun. The main source of energy for heating the corona is believed to be the magnetic field which dominates the corona. Magnetic reconnection is probably the most important mechanism for releasing magnetic energy and may, therefore, be important for coronal heating or micro flaring. The best observational examples of reconnection in the corona are thought to be X ray bright points, which are small scale brightenings seen randomly throughout the whole corona. Theoretical models can not only explain the key observations relating to bright points, but they can also explain the complex three dimensional structures often seen in bright points. In these models magnetic neutral points play a significant role as the centres for reconnection both in two and three dimensions. Dr. Aradhna Sharma "Role of Magnetic Reconnection in Coronal Heating" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-4 , June 2022, URL: https://www.ijtsrd.com/papers/ijtsrd50179.pdf Paper URL: https://www.ijtsrd.com/physics/other/50179/role-of-magnetic-reconnection-in-coronal-heating/dr-aradhna-sharma
1. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
Upsilon Polarization and Event Activity
Brandon McKinzie∗
Advisors: Manuel Calderón de la Barca Sánchez, Daniel Cebra
Abstract
This paper consists of research from two projects both focused on the Upsilon meson. For the first
project, an estimate for the systematic uncertainty associated with the polarization of the Upsilon meson
is presented for the LHC heavy-ion collision energy of
√
sNN = 2.76 TeV. Kinematic cuts are applied to
simulated data in order to model the acceptance of the CMS detector. We find that Upsilon acceptance
varies as a function of pT, with, when no kinematic cuts are applied, as high as a twelve-percent difference
(at low pT) and, when kinematic cuts are applied, as high as a four-percent difference (at mid pT). For the
second project, Upsilon yields are extracted from STAR data containing Υ(nS) candidates produced in
p-p collisions at
√
sNN = 200 GeV. The event-normalized Υ(nS) cross-sections are plotted as a function of
charged-particle multiplicity and then compared to recent findings from the CMS collaboration, wherein a
highly positive correlation was found between these two variables. For the case at STAR, however, the
correlation is less pronounced, possibly due to a lack of event statistics.
1. Introduction
The Upsilon meson (Υ) is important for studying temperature and deconfinement in the Quark-Gluon
Plasma(QGP). In such a state, the strong-force potential responsible for quark-antiquark confinement is
expected to be screened by partons in the surrounding medium[1]. As a consequence, the Υ(nS)1 energy
states are expected to sequentially melt, meaning the higher energy states will be more suppressed than the
lower energy states. Such suppression has been observed at both CMS[2] and at STAR[3]. The dissociation
of each Υ(nS) bound state depends on the temperature, so studying the level of this dissociation in heavy-ion
collisions, when compared to p-p collisions, provides an indirect temperature measurement of the QGP.
In addition, the large mass of the Υ allows for stronger theoretical predictions regarding its properties
when compared to more relativistic quarkonia like the J/Ψ meson. [4]. Therefore, analyzing the Upsilon at
varying energy levels and with different colliding species is a powerful probe for revealing the properties
of the QGP.
In order to accurately infer characteristics of the QGP, one must have a thorough understanding of the
properties of the Upsilon itself. A current unknown property of the Υ is the angle at which its daughter
particles, typically two back-to-back leptons, are emitted as viewed from the Υ rest frame[4]. This frame
of reference is referred to as the Center-of-Mass(CM) Helicity Frame, also known as the Recoil Frame[5].
Letting the Υ momentum lie along the x-axis, the following proportionality between the number of dileptons
produced at a given polarization angle (with respect to the momentum x-axis) and the degree of polarization
is found to be 2
dN
dcos(θ∗)
∝ 1 + αcos2
(θ∗
) (1)
where α is the chosen polarization parameter, defined as
α =
σT − 2σL
σT + 2σL
(2)
∗Funded by NSF grant PHY-1263201
1where n may equal 1, 2, or 3. Υ(1S) is the ground state and larger n corresponds to higher energy states. (This is analogous to
electron energy levels in the hydrogen atom, for example.)
2A more in-depth treatment of polarization parameters may be found in Ref.[4]
1
2. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
relating the transverse and longitudinal components of the polarization production cross sections. It should
be emphasized that full transverse polarization (α = 1) would be physically realized as a preferential
decay of the Υ to a lepton pair with the leptons’ momenta being parallel/antiparallel to the Υ direction of
momentum. Conversely, fully longitudinal polarization (α = −1) is associated with lepton-pair production
perpendicular to the Υ momentum.
Results from the D∅ and CDF Collaborations at Fermilab disagree with regard to measured levels of
polarization[6][7]. Furthermore, calculations from non-relativistic Quantum Chromodynamics (nrQCD)
predict strong transverse polarizations for high Υ pT [8], which neither D∅ nor CDF observed. The current
indecisive state of polarization measurements calls for an estimate of the systematic uncertainty associated
with varying degrees of Υ polarization. While such estimates have been made for the STAR detector
[5], the same cannot be said for the CMS detector. One of the primary aims of this paper is to provide
this systematic uncertainty in order to explore possible relationships between the polarization, detector
acceptance, and Υ pT.3
Another interesting observation has recently been found by CMS regarding the event-normalized produc-
tion cross sections of the Υ as a function of two measures of event activity, charged-particle multiplicity and
transverse energy.[9]. More importantly, the charged-particle tracks are detected in the region | η |< 2.4,
the same kinematic region as the observed Upsilon. Conversely, the transverse energy measurements
are made in the forward region 4.0 <| η |< 5.2 , far from the Upsilon’s kinematic region and thus less
likely to be correlated with Upsilon production. As shown in Figure 1, p-p collisions seem to produce
relatively more Upsilons than expected4 when measured as a function of the aforementioned central-region
charged-particle multiplicity. This region is expected to have particles more directly correlated with Upsilon
production, as illustrated by the sharp increase for the p-p case. However, the positive correlation from
pPb and PbPb collisions appears to be linear with a slope of unity, as opposed to the nearly parabolic
correlation suggested by the p-p data.
When the Υ production cross sections are measured as a function of transverse energy deposition in the
forward region, 4.0 <| η |< 5.2, the correlation is linear with a slope of unity for all three collision scenarios.
The difference between the two plots suggests event activity in the central region has a more positive, and
perhaps more direct, correlation with Υ production than event activity in the forward region. A possi-
total
〉
|<2.4η|
tracks
N〈/
|<2.4η|
tracksN
0 0.5 1 1.5 2 2.5 3 3.5 4
〉(1S)ϒ〈(1S)/ϒ
0
1
2
3
4
5
6
7
CMS
| < 1.93
CM
|y
〉(1S)ϒ〈
(1S)ϒ
| < 2.4
CM
|y
= 2.76 TeVspp
= 5.02 TeVNNspPb
= 2.76 TeVNN
sPbPb
total
〉
|>4η|
T
E〈/
|>4η|
TE
0 0.5 1 1.5 2 2.5 3 3.5 4
〉(1S)ϒ〈(1S)/ϒ
0
1
2
3
4
5
6
7
CMS
| < 1.93
CM
|y
〉(1S)ϒ〈
(1S)ϒ
| < 2.4
CM
|y
= 2.76 TeVspp
= 5.02 TeVNNspPb
= 2.76 TeVNN
sPbPb
Figure 1: Data from CMS published April 28, 2014. Both Y-axes are event-normalized Υ(nS) yields, where the
normalization is simply the average event yield from the full dataset. The X-axes are (left) the event-
normalized number of tracks found in the central region | η | < 2.4 and (right) the event-normalized values
of transverse energy deposited in the HF calorimeter. Data is overlaid from proton-proton, proton-lead, and
lead-lead collisions.
3This will be the first of two projects discussed, and sections 2 - 4 will contain further information pertaining to this project.
4"Expected" here just means along the dotted line. The line is simply shown for illustrative purposes and does not originate from
any model calculations.
2
3. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
ble interpretation for this is the occurence of multiple parton-parton interactions in a given p-p collision [10].
Interestingly, the cross sections for multi-partion interactions are expected to increase with increasing
energy [11]. If so, it would be of value to study Υ yields against event activity in detectors designed for
different energies than CMS, such as the STAR detector at RHIC. Here I attempt to replicate the CMS
results below using data collected in pp-collisions at STAR in the year 2012. A similar positive correlation
is found between event-normalized Υ yields and charged-particle multiplicity, although with not nearly
enough statistics to make the same conclusions suggested by the CMS data.
2. Detectors and Event Selection
Both the polarization and event activity analyses assume knowledge of certain methods of detection
incorporated at particle accelerators. To familiarize the reader with such methods, a brief overview of the
two relevant detectors will be presented.
2.1 Compact Muon Solenoid (CMS)
One of the primary motivations for building the CMS detector was to identify muons emitted by particles
in a collision[12]. This characteristic allows for the analysis of the Upsilon via a decay into a lepton pair,
such as a dimuon. Muons are first identified by whether or not they make it to the muon detectors after
passing through the electromagnetic and hadronic calorimeters which stop virtually all other particles.
Then properties of the muons, such as momenta, may be reconstructed by measuring how much they
bend in the presence of the 4-T superconducting magnet’s field. The primary method of Υ identification,
then, is through analysis of kinematic properties of muon pairs recorded by the muon system in order to
reconstruct the Υ decay vertex.
CMS also covers a massive solid angle with respect to the collision vertex. Muon tracks may be identified
in the pseudorapidity region | η |< 2.4, which allows for a tremendous amount of event statistics in a given
collision. In addition, the Hadron Forward (HF) calorimeters cover the region, 2.9 <| η |< 5.2, providing
forward event activity measurements crucial to ET analyses such as Figure 1(right).
2.2 Solenoidal Tracker at RHIC (STAR)
The STAR detector was constructed to study strongly-interacting particles, such as the Upsilon meson,
produced in ultrarelativistic collisions[13]. The goal of STAR is to understand hadron interactions at high
energy densities and will thus provide the comparison needed to further interpret the high correlations
observed at CMS. Charged particle identification is done via the Time Projection Chamber (TPC) in con-
junction with the 0.5 T magnetic field. Since the STAR detector has such different systematics than CMS,
similar physics results from each provides strong support for arguing that the observations are indeed
valid physics rather than spurious detector effects.
Although construction of a Muon Telescope Detector(MTD) has recently reached completion [14], the data
analyzed in this paper was reconstructed from 2012 p-p collisions in which Υ identification was done by the
Barrel Electromagnetic Calorimeter(BEMC)[15]. Here a threshold of electron energy deposition of approx.
4.2 GeV was required in one of the towers (referred to as the "high tower"), along with an associated electron
candidate patch on the opposite side of the detector(referred to as the "trigger patch"). Relevant quantities
such as nσe and the invariant mass of electron track-pairs are then recorded for further scrutiny.
3
4. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
3. Computational Methods
The polarization analysis to follow was constructed entirely in PYTHIA[16], with all plots generated using
ROOT [17]. Parton distribution functions are taken from the MRSTMCal libraries under LHAPDF and
relevant heavy-flavor customizations are employed to ensure all simulations emulate past experimental
observations.
All polarization simulations are based off generating millions of proton-proton collisions, with the require-
ment that each event produces an Υ(1S) which then decays exclusively into a dimuon. All the relevant
kinematic variables associated with the Υ(1S), µ+, and µ− are then stored in an ntuple to be used for
further analysis. Using α as previously defined in (2), the Υ pT is weighted by (2) and plotted for each
polarization case: unpolarized(α = 0), transverse(α = 1), and longitudinal(α = -1). A pseudorapidity cut is
then applied to each of the three datasets. For STAR the cut is | η |<1.0; For CMS the cut is | η |<2.4. The
acceptance plots are then simply the ratio of the cut data subset over the initial dataset. Another similar
process is done in which the initial dataset consists only of events in which the muons satisfied certain
kinematic properties (to be discussed later). These plots will be referred to as the kinematic acceptance
plots to distinguish them from the prior, uncut baseline.
4. Polarization Acceptance Plots
Before analyzing possible polarization effects at CMS, a simulation is made to emulate STAR to match
results already published. These polarization acceptances for STAR are shown in Figure 2 5. They are
presented here primarily to convince the reader of the validity of the plots to follow. Notable features of the
superimposed acceptance include the crossover around 3 GeV/c and the monotonic increase in acceptance
for higher pT. The acceptance differences for low pT are intuitive when one visualizes the Υ decay as seen
by the lab frame. For example, if full transverse polarization is assumed(i.e. decay along Υ momentum
axis), and the Υ has low pT, the dimuon will have momentum primarily along the z-axis and will thus not
be detected.
(1S)ϒof
T
p
0 1 2 3 4 5 6 7 8 9 10
Acceptance
0.25
0.3
0.35
0.4
0.45
0.5
0.55
Unpolarized
Transverse
Longitudinal
(1S) Polarization Acceptancesϒ
(1S)ϒof
T
p
0 1 2 3 4 5 6 7 8 9 10
Acceptance
0.44
0.46
0.48
0.5
0.52
0.54
0.56
0.58
0.6
0.62
Unpolarized
Transverse
Longitudinal
(1S) Polarization Acceptancesϒ
Figure 2: Acceptance yields for varying degrees of Υ(1S) polarization simulated at 200 GeV for the STAR detector. On
the left, only a pseudorapidity cut of | η |< 1.0 is applied to the full dataset, with the ratio Ncut
Nall
defined as the
acceptance. On the right, baseline cuts of p
(1)
T < 4 GeV/c, p
(2)
T < 2.5 GeV/c, and cos(θ) < 0.5 are applied.
From there, the same pseudorapidity cut | η |< 1.0 is applied, with the ratio
Nηcut
Nbaseline
defined as the acceptance.
5The plots indeed mirror those produced by STAR member Thomas Ullrich [5].
4
5. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
(1S)ϒpT of
0 2 4 6 8 10 12 14 16 18
Acceptance
0.5
0.55
0.6
0.65
0.7
0.75
0.8 Unpolarized
Transverse
Longitudinal
(1S) Polarization Acceptancesϒ
(1S)ϒpT of
0 2 4 6 8 10 12 14 16 18
Acceptance
0.66
0.68
0.7
0.72
0.74
0.76
0.78
0.8
0.82
0.84
Unpolarized
Transverse
Longitudinal
(1S) Polarization Acceptancesϒ
Figure 3: Acceptance yields for varying degrees of Υ(1S) polarization simulated at 2.76 TeV for the CMS detector. On
the left, a pseudorapidity cut of | η |< 2.4 is applied to the full dataset, with the ratio Ncut
Nall
defined as the
acceptance. On the right, baseline cuts of p
(1)
T < 4 GeV/c and p
(2)
T < 3.5 GeV/c are applied. From there, the
same pseudorapidity cut | η |< 2.4 is applied, with the ratio
Nηcut
Nbaseline
defined as the acceptance.
The CMS analysis was then constructed by the processes introduced above in Section 3. Proton-proton
collisions are run at
√
s = 2.76TeV as is typically done at CMS, and the cut of | η |< 2.4 emulates the
acceptance region of the muon detector system. The acceptances plots are shown above in Figure 3.
The shapes of the acceptances are visually similar to those found for the STAR detector with expected
differences. For example, the acceptance crossover in the left figure occurs at a higher value of Υ pT and the
absolute values of acceptance are higher. This can be explained by the higher range of acceptance allowed
at CMS compared to STAR’s acceptance of | η |< 1.0 .
The kinematic acceptances indicate that the polarization systematic uncertainty is smaller at CMS than
at STAR. The level of systematic uncertainty is estimated by the vertical distances between polarization
cases in a given bin. The difference communicates how much the expected Υ yield may vary depending
on the true degree of polarization. Since a pT threshold is often set as a trigger for dimuon candidates
detected in a collision, as was done for the simulated kinematic acceptances, this plot indicates how the
true polarization may affect Υ yields for a typical CMS run.
The statistical errors are negligibly small due to the high number of events simulated and would decrease
further with even more simulated collisions. They were calculated using a Bayesian approach, briefly
outlined as follows: Consider a single bin with content k/n, where k is a subset of n total events that
passed a certain efficiency cut. Rather than estimating the efficiency (denoted ξ)to be merely k/n, we use
a probability distribution relating the probability that the true efficiency is ξ, given that k out of n events
passed the cut [18],
P(ξ; k, n) =
(n + 1)!
k!(n − k)!
ξk
(1 − ξ)n−k
(3)
which has been derived from Bayes’ theorem assuming a uniform prior for P(ξ; n) , so as not to favor any
particular efficiency value. From this distribution we find the standard deviation:
σ =
(k + 1)
(n + 2)
(k + 2)
(n + 3)
−
(k + 1)2
(n + 2)2
(4)
This was the quantity used to calculate the statistical error associated with each bin for the polarization
acceptance plots6
6The full derivation may be found in Ref.[18].
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6. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
The takeaway from these acceptances is a new intuition regarding how polarization affects Upsilon yields,
or acceptances, at a particle detector like CMS. When extracting Upsilons from a raw dataset, a prior
expectation of how many Upsilons one ought to observe is inevitably factored into the analysis, and could
thus skew the results if polarization effects are not properly taken into account.
5. Yield Extraction and Event Activity at STAR
Motivated by the results from CMS, a 2012 proton-proton dataset from STAR (from section 2.2) is analyzed
for any correlations between Υ(nS) yields and event activity. The central rapidity region’s event activity will
be measured by a value called reference multiplicity, defined as the number of charged particle tracks within
a given pseudorapidity range. This analysis is primarily interested in comparing the Υ yields in given
ranges of reference multiplicity as a means of comparison to the recent CMS measurements. Accordingly,
the method of analysis will be to bin the multiplicity in two distinct rapidity bins, with one bin in the same
acceptance region as the Upsilon and with the other in a slightly more forward/backward region.
First, the data with all Upsilon candidates is collected and preliminary cuts are applied. Guided by past
results, the data is cut to only allow electrons satisfying the following 7:
−1.2 < nσe < 3 and 0.7 <
Ei
pi
< 1.3 and 8.0 < me+e− < 11
Using these cuts, the invariant mass of the dielectrons are plotted in a histogram in Figure 4(left). A color
distinction is made between electron pairs of opposite charge (red) and of like charge (blue). Oppositely
charged pairs are expected to have originated from an Upsilon, due to charge conservation (the Υ has zero
charge). The like-charge electron pairs are considered to be background originating from processes such as
b − ¯b production and the Drell-Yan process[19].
To maximize the number of good Upsilon candidates from this dataset, we want to maximize a quantity
called the effective signal, Se f f [20]:
Se f f =
S
2B
S + 1
where 8
S =
11
8
(munlikeCharge − mlikeCharge)dm and B =
11
8
mlikeChargedm
A maximized Se f f is associated with a maximized Υ yield extracted from the dataset. The primary method
employed here was to scan different ranges of possible cuts to the data and, for each cut range, to find
the value of Se f f . Once a maximum is found in this abstract cut space, those cuts are kept and applied
to the dataset. Figure 4 (right) shows two examples of searched cut ranges for the quantities nσe and
E1
p1
. In all these cut scans, the following global cut is applied to the data being scanned: 0.5 <| y |< 1.5
. In addition, Se f f is evaluated by integrating outside the Υ mass range defined in the integrals above.
These restrictions are applied to ensure no artificial optimization is occurring so as to avoid possible
autocorrelations. Upsilons are expected in the rapidity range | y |< 0.5 and that is the cut applied to all
later fits. The maximized Se f f is simply used as a guide for which cuts ought to be applied to future fits.
7Any i’s just means the cut was applied to both electrons
8Henceforth, all variables denoted m are referring to the invariant mass of the electron-pair.
6
7. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
)2
(Gev/ceem
4 6 8 10 12 14 16 18 20
counts
0
20
40
60
80
100
Invariant Mass of Back-to-Back Electrons
likeSign
Invariant Mass of Back-to-Back Electrons
0.901408 0.0410959 0.617284 1.88462 0.555556 0.5
1.47561 0.387597 0.857868 2.67407 2.9697 0.222222
1.63636 0.510638 1.0274 2.1039 2.08642 0.333333
1.95442 0.757576 1.25108 3.28571 3.32184 1.125
1.35294 0.258786 0.585366 2.06286 2 0.641026
1.80893 0.444444 0.765625 2.40984 2.46154 0.581395
low
(0.400000) (0.500000) (0.600000) (0.700000) (0.800000) (0.900000)
high
(1.100000)
(1.200000)
(1.300000)
(1.400000)
(1.500000)
(1.600000)
0.5
1
1.5
2
2.5
3
Effective Signal E/p cuts
1.6484 2.26154 2.54913 2.35948 2.41791 1.49558
2.38017 3.12963 3.27225 2.88095 2.7027 2.03175
2.15918 2.85388 2.96907 2.57895 2.16 1.53125
2.1417 2.82805 2.93878 2.54913 2.13158 1.50769
1.77108 2.3722 2.44444 2.06286 1.66234 1.09091
1.77108 2.3722 2.44444 2.06286 1.66234 1.09091
low
(-1.500000) (-1.400000) (-1.300000) (-1.200000) (-1.100000) (-1.000000)
high
(1.000000)
(1.500000)
(2.000000)
(2.500000)
(3.000000)
(3.500000)
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
3.2
cutseσEffective Signal n
Figure 4: (left) Dielectron invariant mass distribution from 2012 STAR Υ(nS) candidate dataset. A clear peak can be
seen at 9.46 GeV/c2, the mass of the Υ(1S) meson. (right) Scanning the cut space for maximum Se f f . The
leftmost scan is on electron E
p cuts, where the rightmost scan is on nσe cuts. The x-axis corresponds to a
low-end value for a cut range, and the y-axis corresponds to the high-end value. Each plot scans a single
variable cut range. Many plots are produced, each corresponding to different variables in order to observe
how each variable affects the Se f f .
With a potential maximum Se f f , the invariant mass data with optimized cuts is plotted against a fitted
Crystal-Ball function (Figure 5). From the fitted model, Υ(nS) yields are extracted with statistical errors
taken into account. The data is integrated over all reference multiplicity, defined as the number of tracks
found in the detector regions
0 <| ηe+e− |< 0.5 [refMult1] or 0.5 <| ηe+e− |< 1.0 [refMult2]
depending on which reference multiplicity is being analyzed. The former is the region closest to midrapidity
(where the Upsilon is measured) and the latter is in a bin that is slightly more forward/backward. For
compactness, only refMult1 is shown in Figure 5, whereas both are shown in Figure 6. Regardless of which
reference multiplicity is used, an average of fifty-five Upsilons were found per event in the dataset.
m
7 8 9 10 11 12 13 14 15
Events/(0.2)
0
2
4
6
8
10
12
14
16
18
20
22
24
Opp sign
m
7 8 9 10 11 12 13 14 15
Events/(0.2)
0
1
2
3
4
5
6
7
8
Same-sign
)2
(GeV/ceem
8 9 10 11 12 13
0
2
4
6
8
10
12
14
16
18
20
22
STAR Prelminary
= 200 GeVNN
sp+p
|<0.5, 0<refMult1<100ee
|y
- -+N+ +N
+ -N
Comb. Background (CB)
bCB + Drell-Yan + b
(1S+2S+3S)ϒ+bCB + DY + b
ϒ+bIntegral of CB + DY + b
Figure 5: Invariant mass data fit to a CB function integrated over all values of reference multiplicity. From left to right,
invariant mass is plotted for (1) unlike-charge electron pairs, (2) like-charge electron-pairs, and (3) for both,
using a more sophisticated fitting macro. These fits were applied to the same cut dataset and they extracted
an average of fifty-five Upsilons per event.
7
8. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
| < 0.5η|
tracks
N
0 5 10 15 20 25 30 35
counts/integral
-410
-3
10
-210
-110
MinBias RefMult
(nS) RefMultϒ
| < 1.0η0.5 < |
tracks
N
0 5 10 15 20 25 30 35
counts/integral
-410
-3
10
-210
-110
MinBias RefMult
(nS) RefMultϒ
>
| < 0.5η|
tracks
/ <N
| < 0.5η|
tracks
N
0 0.5 1 1.5 2 2.5 3
(nS)>ϒ(nS)/<ϒ
0
1
2
3
4
5
6
Upsilon Yield vs. Reference Multiplicity(1)
>
| < 1.0η0.5 < |
tracks
/ <N
| < 1.0η0.5 < |
tracks
N
0 0.5 1 1.5 2 2.5 3 3.5 4
(nS)>ϒ(nS)/<ϒ
0
1
2
3
4
5
6
Upsilon Yield vs. Reference Multiplicity(2)
Figure 6: (left) Reference multiplicity distributions plotted for all events[blue] and a subset of these events with Υ
candidates [red]. A vertical dashed line is drawn to illustrate where reference multiplicities were divided
to produce the plot on the right. (right) Event-normalized Υ yields versus their event-normalized reference
multiplicities (same axes as in Figure 1 (left). Lack of statistics is due to having only half of the data expected.
Now that the average number of Upsilons found in all events using optimized cuts has been found, this
value will be used as the event average, < Υ(nS) > , or activity-integrated value of Upsilons produced. The
relationship of interest is whether or not the fractional Upsilon yield,
Υ(nS)
<Υ(nS)>
(where the numerator is the
average Υ(nS) yield for a given reference multiplicity range), exhibits a positive correlation when plotted
against the event-normalized reference multiplicity,
re f Mult
<re f Mult> . To plot these quantities, we need to split up
the reference multiplicity distributions and extract the average Υ(nS) from each (Figure 6). The dataset
extends out to a reference multiplicity of one-hundred, but the vast majority of events recorded a reference
multiplicity value under twenty. To have a (somewhat) more even split, then, the data is cut into two sections
corresponding to events with less than ten tracks found and events with more than ten tracks found. The
average Υ(nS) yields found on either side of this cut are extracted and their event-normalized values are
plotted as a function of the corresponding event-normalized reference multiplicity values (Figure 6(right)).
Interpretation of these plots is limited, due to the large statistical uncertainties and lack of data points.
Using this dataset, more points would raise the statistical uncertainty, and less points would offer nothing
for an analysis. Nonetheless, an undeniable positive correlation exists. What is uncertain is whether or not
this correlation is linear (as was originally expected) or perhaps quadratic (as the CMS results appear to
suggest). More data will be needed to confirm or deny the possibility of a nonlinear correlation.
6. Conclusions
The relative acceptances associated with the polarization of the Upsilon meson at CMS do not appear to
differ drastically from the same acceptances simulated for STAR. The vertical distances between the three
polarization cases indicates the associated systematic uncertainty. The absolute systematic errors for CMS
are identical to those for STAR at low Υ pT and no applied kinematic cuts. They differ, however, in the
case of kinematic acceptances such that the systematic error is lower at CMS when compared to STAR. This
suggests that polarization effects on detector acceptance may depend on the event energy.
The event activity results from STAR suggest a positive correlation between event-normalized Upsilon
yields and the corresponding event-normalized reference multiplicities, albeit with too few statistics to
provide for stronger conclusions. It should be noted that, when experimenting with different regions of
reference multiplicity to extract from for Figure 6(left), the level of positive correlation varied both above
and below the line with slope unity. Nonetheless, there is a clear (expected) positive correlation between
Υ(nS) yields and central event activity.
8
9. Upsilon Polarization and Event Activity • August 2014 • UC Davis REU
7. Acknowledgements
The work presented here would not have been possible without all the help and support given by the
National Science Foundation, Dr. Rena Zieve, and the Nuclear Physics Group at UC Davis. In particular,
graduate students Chad Flores, Anthony Kesich, and Chris Flores have played direct roles in the above
analyses and have greatly expanded my knowledge in the realm of high-energy physics. Professors Manuel
Calderón and Daniel Cebra lead an excellent research group and deserve the highest commendation for
their interest in undergraduate outreach. Professor Calderón in particular has introduced me to this field,
guided me throughout every step of my research, and been a role model for the research scientist and
person I’d like to become. I cannot express my gratitude enough for being given the opportunity to work
with such fantastic individuals.
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