The document summarizes measurements of the beam asymmetry Σ in the photoproduction of negative pions off neutrons using the Graal collaboration's polarized photon beam and detector setup. Key points:
- Beam asymmetry measurements were made for the reaction γn → π−p from 700-1500 MeV photon energy and over a wide angular range.
- Event identification and background reduction was achieved through constraints on additional neutral particles, coplanarity of pion and proton, Fermi momentum reconstruction, and a multivariate cut.
- Results are compared to recent partial wave analyses to help constrain isospin transition amplitudes in pion photoproduction on nucleons.
28 Measurement of η photoproduction on the proton from threshold to 1500-MeV ...Cristian Randieri PhD
Measurement of η photoproduction on the proton from threshold to 1500-MeV - The European Physical Journal A, Hadrons and Nuclei, August 2007, Vol. 33, N. 2, pp. 169-184, ISSN: 1434-6001, doi: 10.1140/epja/i2007-10439-9
di O. Bartalini, V. Bellini, J. P. Bocquet, P. Calvat, M. Capogni, L. Casano, M. Castoldi, A. D'Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, C. Gaulard, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, M. Guidal, E. Hourany, R. Kunne, A. Lapik, P. Levi Sandri, A. Lleres, F. Mammoliti, G. Mandaglio, D. Moricciani, A. N. Mushkarenkov, V. Nedorezov, L. Nicoletti, C. Perrin, C. Randieri, D. Rebreyend, F. Renard, N. Rudnev, T. Russew, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna (2007).
Abstract
Beam asymmetry and differential cross section for the reaction gamma+p->eta+p were measured from production threshold to 1500 MeV photon laboratory energy. The two dominant neutral decay modes of the eta meson, eta->2g and eta->3pi0, were analyzed. The full set of measurements is in good agreement with previously published results. Our data were compared with three models. They all fit satisfactorily the results but their respective resonance contributions are quite different. The possible photoexcitation of a narrow state N(1670) was investigated and no evidence was found.
42 Beam Asymmetry Σ of the π- Photoproduction off Neutron - International Jou...Cristian Randieri PhD
Beam Asymmetry Σ of the π- Photoproduction off Neutron - International Journal of Modern Physics E, June 2010, Vol. 19, N. 5-6, pp. 965-976, doi: 10.1142/S0218301310015412
di G. Mandaglio, V. Bellini, J. P. Bocquet, L. Casano, A. D'Angelo, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, A. S. Ignatov, A. M. Lapik, P. Levi Sandri, A. Lleres, F. Mammoliti, M. Manganaro, D. Moricciani, A. N. Mushkarenkov, V. G. Nedorezov, C. Randieri, D. Rebreyend, N. V. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna (2010)
Abstract
We present the analysis of data performed in order to identify the events of the γ + n → π- + p reaction obtained by bombarding a liquid Deuterium target with a polarised γ beam of 0.55-1.5 GeV at the Graal-experiment. We show the effect of different kinematic and hardware constraints used to reduce the contamination coming from the concurrent reaction channels. By the simulation we estimate the contamination degree due to the other reaction channels so we can test the reliability of our method. We describe a new three-dimensional cut based on the Fermi momentum reconstruction and its effect on the suppression of the concurrent double charged pion photoproduction. We present the preliminary beam asymmetry Σ of the π- fotoproduction off quasi-free neutron up to about θc.m., π- = 165° together with some theoretical multipolar analysis. For a comparison we also report the data present in literature on the same reaction for Eγ =850-1740 MeV and θc.m., π- ≤105°.
36 Measurement of Σ beam asymmetry in π0 photoproduction off the neutron in t...Cristian Randieri PhD
Measurement of Σ beam asymmetry in π0 photoproduction off the neutron in the second and third resonances region - The European Physical Journal A, Hadrons and Nuclei, November 2009, Vol. 42, N. 2, pp. 151-157, ISSN: 1434-6001, doi: 10.1140/epja/i2009-10870-x
di R. Di Salvo, A. Fantini, G. Mandaglio, F. Mammoliti, O. Bartalini, V. Bellini, J. P. Bocquet, L. Casano, A. D’angelo, J. P. Didelez, D. Franco, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, M. Guidal, E. Hourany, R. Kunne, A. Lapik, P. Levi Sandri, A. Lleres, M. Manganaro, D. Moricciani, A. N. Mushkarenkov, V. Nedorezov, C. Randieri, D. Rebreyend, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna, A. Fix, S. S. Kamalov, L. Tiator (2009)
Abstract
The Σ beam asymmetry in the photoproduction of neutral pions from quasi-free nucleons in a deuteron target was measured for the first time between 0.60 and 1.50GeV, with the GRAAL polarized and tagged photon beam. The asymmetry values from the quasi-free proton were found equal to the ones extracted from a pure proton target. The asymmetries from quasi-free proton and quasi-free neutron were found equal up to 0.82GeV and substantially different at higher energies. The results are compared with recent partial-wave analyses.
X-RAY PHOTOELECTRON SPECTROSCOPY AND ELECTRON SPIN RESONANCEKishan Kasundra
INTRODUCTION OF XPS
MECHANISM OF XPS
CHEMICAL SHIFT IN XPS
STRENGTHS AND LIMITATIONS OF XPS
INTRODUCTION OF ESR
MECHANISM OF ESR
PRESENTATION OF ESR SPECTRUM
APPLICATION OF ESR
ADVANTAGES AND DISADVANTAGES OF ESR
28 Measurement of η photoproduction on the proton from threshold to 1500-MeV ...Cristian Randieri PhD
Measurement of η photoproduction on the proton from threshold to 1500-MeV - The European Physical Journal A, Hadrons and Nuclei, August 2007, Vol. 33, N. 2, pp. 169-184, ISSN: 1434-6001, doi: 10.1140/epja/i2007-10439-9
di O. Bartalini, V. Bellini, J. P. Bocquet, P. Calvat, M. Capogni, L. Casano, M. Castoldi, A. D'Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, C. Gaulard, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, M. Guidal, E. Hourany, R. Kunne, A. Lapik, P. Levi Sandri, A. Lleres, F. Mammoliti, G. Mandaglio, D. Moricciani, A. N. Mushkarenkov, V. Nedorezov, L. Nicoletti, C. Perrin, C. Randieri, D. Rebreyend, F. Renard, N. Rudnev, T. Russew, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna (2007).
Abstract
Beam asymmetry and differential cross section for the reaction gamma+p->eta+p were measured from production threshold to 1500 MeV photon laboratory energy. The two dominant neutral decay modes of the eta meson, eta->2g and eta->3pi0, were analyzed. The full set of measurements is in good agreement with previously published results. Our data were compared with three models. They all fit satisfactorily the results but their respective resonance contributions are quite different. The possible photoexcitation of a narrow state N(1670) was investigated and no evidence was found.
42 Beam Asymmetry Σ of the π- Photoproduction off Neutron - International Jou...Cristian Randieri PhD
Beam Asymmetry Σ of the π- Photoproduction off Neutron - International Journal of Modern Physics E, June 2010, Vol. 19, N. 5-6, pp. 965-976, doi: 10.1142/S0218301310015412
di G. Mandaglio, V. Bellini, J. P. Bocquet, L. Casano, A. D'Angelo, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, A. S. Ignatov, A. M. Lapik, P. Levi Sandri, A. Lleres, F. Mammoliti, M. Manganaro, D. Moricciani, A. N. Mushkarenkov, V. G. Nedorezov, C. Randieri, D. Rebreyend, N. V. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna (2010)
Abstract
We present the analysis of data performed in order to identify the events of the γ + n → π- + p reaction obtained by bombarding a liquid Deuterium target with a polarised γ beam of 0.55-1.5 GeV at the Graal-experiment. We show the effect of different kinematic and hardware constraints used to reduce the contamination coming from the concurrent reaction channels. By the simulation we estimate the contamination degree due to the other reaction channels so we can test the reliability of our method. We describe a new three-dimensional cut based on the Fermi momentum reconstruction and its effect on the suppression of the concurrent double charged pion photoproduction. We present the preliminary beam asymmetry Σ of the π- fotoproduction off quasi-free neutron up to about θc.m., π- = 165° together with some theoretical multipolar analysis. For a comparison we also report the data present in literature on the same reaction for Eγ =850-1740 MeV and θc.m., π- ≤105°.
36 Measurement of Σ beam asymmetry in π0 photoproduction off the neutron in t...Cristian Randieri PhD
Measurement of Σ beam asymmetry in π0 photoproduction off the neutron in the second and third resonances region - The European Physical Journal A, Hadrons and Nuclei, November 2009, Vol. 42, N. 2, pp. 151-157, ISSN: 1434-6001, doi: 10.1140/epja/i2009-10870-x
di R. Di Salvo, A. Fantini, G. Mandaglio, F. Mammoliti, O. Bartalini, V. Bellini, J. P. Bocquet, L. Casano, A. D’angelo, J. P. Didelez, D. Franco, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, M. Guidal, E. Hourany, R. Kunne, A. Lapik, P. Levi Sandri, A. Lleres, M. Manganaro, D. Moricciani, A. N. Mushkarenkov, V. Nedorezov, C. Randieri, D. Rebreyend, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna, A. Fix, S. S. Kamalov, L. Tiator (2009)
Abstract
The Σ beam asymmetry in the photoproduction of neutral pions from quasi-free nucleons in a deuteron target was measured for the first time between 0.60 and 1.50GeV, with the GRAAL polarized and tagged photon beam. The asymmetry values from the quasi-free proton were found equal to the ones extracted from a pure proton target. The asymmetries from quasi-free proton and quasi-free neutron were found equal up to 0.82GeV and substantially different at higher energies. The results are compared with recent partial-wave analyses.
X-RAY PHOTOELECTRON SPECTROSCOPY AND ELECTRON SPIN RESONANCEKishan Kasundra
INTRODUCTION OF XPS
MECHANISM OF XPS
CHEMICAL SHIFT IN XPS
STRENGTHS AND LIMITATIONS OF XPS
INTRODUCTION OF ESR
MECHANISM OF ESR
PRESENTATION OF ESR SPECTRUM
APPLICATION OF ESR
ADVANTAGES AND DISADVANTAGES OF ESR
X ray, invisible, highly penetrating electromagnetic radiation of much shorter wavelength (higher frequency) than visible light. The wavelength range for X rays is from about 10-8 m to about 10-11 m, the corresponding frequency range is from about 3 × 1016 Hz to about 3 × 1019 Hz.
19 Double π0 Photoproduction on the Proton at GRAAL - Physical Review Letters...Cristian Randieri PhD
Double π0 Photoproduction on the Proton at GRAAL - The American Physical Society, Physical Review Letters, June 2003, Vol. 90, N. 22, pp. 222001-1-222001-4, ISSN: 0031-9007, doi: 10.1103/PhysRevLett.90.222001
di Y. Assafiri, O. Bartalini, V. Bellini, J. P. Bocquet, S. Bouchigny , M. Capogni, M. Castoldi, A. D'Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, L. Fichen , G. Gervino, F. Ghio, B. Girolami, A. Giusa, M. Guidal, E. Hourany, V. Kouznetsov, R. Kunne, J. M. Laget, A. Lapik, P. Levi Sandri, A. Lleres, D. Moricciani, V. Nedorezov, D. Rebreyend, C. Randieri, F. Renard, N. Rudnev, C. Schaerf, M. Sperduto, M. C. Sutera, A. Turinge, A. Zucchiatti (2003)
Abstract
The double π0 photoproduction off the proton has been measured in the beam energy range of 0.65 1.5GeV. The total and differential cross sections and the Σ beam asymmetry were extracted. The total cross section measured for the first time in the third resonance region of the nucleon shows a prominent peak. The interpretation of these results by two independent theoretical models infers mostly the selective excitation of P11- and D13-nucleon resonances.
Complete Photoproduction Experiments - 12th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon, Virginia, USA, 31 May-4 June 2010. AIP Conference Proceedings, October 2011, Vol. 1374, pp. 17-22, ISSN: 0094-243X, doi: 10.1063/1.3647092
di A. D’Angelo, K. Ardashev, C. Bade, O. Bartalini, V. Bellini, M. Blecher, J. P. Bocquet, M. Capogni, A. Caracappa, L. E. Casano, M. Castoldi, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, C. Gibson, B. Girolami, A. Giusa, H. Glu, K. Hicks, S. Hoblit, A. Honig, T. Kageya, M. Khandaker, O. C. Kistner, S. Kizilgul, S. Kucuker, A. Lapikf, A. Lehmann, P. Levi Sandri, A. Lleres, M. Lowry, M. Lucas, J. Mahon, F. Mammoliti, G. Mandaglio, M. Manganaro, L. Miceli, D. Moricciani, A. Mushkarenkovf, V. Nedorezovf, B. Norum, M. Papb, B. Preedom, H. Seyfarthb, C. Randieri, D. Rebreyend, N. Rudnevf, G. Russo, A. Sandorfi, C. Schaerf, M. L. Sperduto, H. Stroher, M. C. Sutera, C. E. Thorn, A. Turingef, V. Vegna, C. S. Whisnanth, K. Wang, X. Wei (2011)
Abstract
The extraction of resonance parameters from meson photo-reaction data is a challenging effort, that would greatly benefit from the availability of several polarization observables, measured for each reaction channel on both proton and neutron targets. In the aim of obtaining such complete experiments, polarized photon beams and targets have been developed at facilities, worldwide. We report on the latest results from the LEGS and GRAAL collaborations, providing single and double polarization measurements on pseudo-scalar meson photo-production from the nucleon.
45 Evidence for a narrow N* (1685) resonance in quasifree Compton scattering ...Cristian Randieri PhD
Evidence for a narrow N* (1685) resonance in quasifree Compton scattering on the neutron - The American Physical Society, Physical Review C, February 2011, Vol. 83, N. 2, pp. 022201-1-022201-4, ISSN: 0556-2813, doi: 10.1103/PhysRevC.83.022201
di V. Kuznetsov, M. V. Polyakov, V. Bellini, T. Boiko, S. Chebotaryov, H.-S. Dho, G. Gervino, F. Ghio, A. Giusa, A. Kim, W. Kim, F. Mammoliti, E. Milman, A. Ni, I. A. Perevalova, C. Randieri, G. Russo, M. L. Sperduto, C. M. Sutera, A. N. Vall (2011)
Abstract
The study of quasifree Compton scattering on the neutron in the energy range of Eγ=0.75–1.5 GeV is presented. The data reveal a narrow peak at W~1.685 GeV. This result, being considered in conjunction with the recent evidence for a narrow structure at W~1.68 GeV in η photoproduction on the neutron, suggests the existence of a nucleon resonance with unusual properties: a mass M~1.685GeV, a narrow width Γ⩽30 MeV, and the much stronger photoexcitation on the neutron than on the proton.
33 Measurement of beam-recoil observables Ox, Oz and target asymmetry T for t...Cristian Randieri PhD
Measurement of beam-recoil observables Ox, Oz and target asymmetry T for the reaction γρ → K+Λ - The European Physical Journal A, Hadrons and Nuclei, February 2009, Vol. 39, N. 2, pp. 149–161, ISSN: 1434-6001, doi: 10.1140/epja/i2008-10713-4
di A. Lleres, O. Bartalini, V. Bellini, J. P. Bocquet, P. Calvat, M. Capogni, L. Casano, M. Castoldi, A. D’Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, C. Gaulard, G. Gervino, F. Ghio, B. Girolami, A. Giusa, M. Guidal, E. Hourany, R. Kunne, V. Kuznetsov, A. Lapik, P. Levi Sandri, F. Mammoliti, G. Mandaglio, D. Moricciani, A. N. Mushkarenkov, V. Nedorezov, L. Nicoletti, C. Perrin, C. Randieri, D. Rebreyend, F. Renard, N. Rudnev, T. Russew, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna (2009)
Abstract
The double polarization (beam-recoil) observables Ox and Oz have been measured for the reac- tion γp → K+Λ from threshold production to E ∼ 1500MeV. The data were obtained with the linearly polarized beam of the GRAAL facility. Values for the target asymmetry T could also be extracted despite the use of an unpolarized target. Analyses of our results by two isobar models tend to confirm the necessity to include new or poorly known resonances in the 1900MeV mass region.
Introduction, Basic Principles, Terminology, Instrumentation, Ionization techniques (EI, CI, FAB, MALDI, and ESI), Mass Analyzer (Magnetic sector instruments, Quadrupole, TOF, and ICR ), and Applications of Mass Spectrometry.
DEVELOPMENT OF OPTICAL PARAMETER CALCULATIONS OF THE PROBES IN WATERDr. Ved Nath Jha
Fiber optic technology with the role of surface plasmons has tremendously advanced the sensing technique of various physical, chemical and biochemical parameters of materials. The working of the optical fiber sensor designed by us is founded on the principle of the absorption of the evanescent waves passing through the optical fiber. The technique is based on the evanescent wave penetration between two dielectric media satisfying the conditions of attenuated total internal reflections (ATR’s). In the present work, the cladding of the fiber is removed by a suitable technique, and Silver nanoparticles are deposited on it. The evanescent light waves passing out of the core of the fiber are absorbed by the metal nanoparticles. The wavelength of maximum absorption is specific to the metal nanoparticles as well as to the dielectric constant of the surrounding medium and occurs when the wavelength of evanescent light resonates with localized surface plasmon (LSP) wavelength of the nanoparticle. Noble metal nanoparticles of Silver and Gold exhibit LSP resonance in the visible region of electromagnetic spectrum. In this article, we report the characteristic parameters of three sensor probes a, b and c developed by researcher.
Laser ablation - optical cavity isotopic spectrometer (LAOCIS) for Mars roversAlexander Bolshakov
Proceedings of SPIE, v. 8385, "Sensors and Systems for Space Applications V"; Baltimore, MD, 2012. ABSTRACT: A concept of a compact device for analyzing key isotopic composition in surface materials without sample preparation is presented. This design is based on an advanced modification of Laser Induced Breakdown Spectroscopy (LIBS). First, we developed Laser Ablation Molecular Isotopic Spectrometry (LAMIS) that involves measuring isotope-resolved molecular emission, which exhibits significantly larger isotopic spectral shifts than those in atomic transitions. Second, we used laser ablation to vaporize the sample materials into a plume in which absorption spectra can be measured using a tunable diode laser. The intrinsically high spectral resolution of the diode lasers facilitates measurements of isotopic ratios. The absorption sensitivity can be boosted using cavity enhanced spectroscopy. Temporal behavior of species in a laser ablation plasma from solid samples with various isotopic composition was studied. Detection of key isotopes associated with signs of life (carbon, nitrogen, hydrogen) as well as strontium and boron in laser ablation plume was demonstrated; boron isotopes were quantified. Isotope-resolved spectra of many other molecular species were simulated. The experimental results demonstrate sensitivity to 86 Sr, 87 Sr, and 88 Sr with spectrally resolved measurements for each of them. It is possible to measure strontium isotopes in rocks on Mars for radiogenic age determination. Requirements for spectral resolution of the optical measurement system can be significantly relaxed when the isotopic abundance ratio is determined using chemometric analysis of spectra.
49 First Measurement of the Σ Beam Asymmetry in η' Photoproduction off the Pr...Cristian Randieri PhD
First Measurement of the Σ Beam Asymmetry in η' Photoproduction off the Proton near Threshold - July 2014
di P. Levi Sandri, G. Mandaglio, O. Bartalini, V. Bellini, J. P. Bocquet, M. Capogni, F. Curciarello, A. D’Angelo, V. De Leo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, C. Gaulard, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, A. Lapik, A. Lleres, F. Mammoliti, 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, V. Vegna and I. Zonta (2014)
Abstract
The Σ beam asymmetry in η' photoproduction off the proton was measured at the GRAAL polarized photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies the asymmetry as a function of the meson emission angle shows a clear structure, more pronounced at the lowest one, with a change of sign around 90°. The results are compared to the existing theories that fail to account for the data.
X ray, invisible, highly penetrating electromagnetic radiation of much shorter wavelength (higher frequency) than visible light. The wavelength range for X rays is from about 10-8 m to about 10-11 m, the corresponding frequency range is from about 3 × 1016 Hz to about 3 × 1019 Hz.
19 Double π0 Photoproduction on the Proton at GRAAL - Physical Review Letters...Cristian Randieri PhD
Double π0 Photoproduction on the Proton at GRAAL - The American Physical Society, Physical Review Letters, June 2003, Vol. 90, N. 22, pp. 222001-1-222001-4, ISSN: 0031-9007, doi: 10.1103/PhysRevLett.90.222001
di Y. Assafiri, O. Bartalini, V. Bellini, J. P. Bocquet, S. Bouchigny , M. Capogni, M. Castoldi, A. D'Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, L. Fichen , G. Gervino, F. Ghio, B. Girolami, A. Giusa, M. Guidal, E. Hourany, V. Kouznetsov, R. Kunne, J. M. Laget, A. Lapik, P. Levi Sandri, A. Lleres, D. Moricciani, V. Nedorezov, D. Rebreyend, C. Randieri, F. Renard, N. Rudnev, C. Schaerf, M. Sperduto, M. C. Sutera, A. Turinge, A. Zucchiatti (2003)
Abstract
The double π0 photoproduction off the proton has been measured in the beam energy range of 0.65 1.5GeV. The total and differential cross sections and the Σ beam asymmetry were extracted. The total cross section measured for the first time in the third resonance region of the nucleon shows a prominent peak. The interpretation of these results by two independent theoretical models infers mostly the selective excitation of P11- and D13-nucleon resonances.
Complete Photoproduction Experiments - 12th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon, Virginia, USA, 31 May-4 June 2010. AIP Conference Proceedings, October 2011, Vol. 1374, pp. 17-22, ISSN: 0094-243X, doi: 10.1063/1.3647092
di A. D’Angelo, K. Ardashev, C. Bade, O. Bartalini, V. Bellini, M. Blecher, J. P. Bocquet, M. Capogni, A. Caracappa, L. E. Casano, M. Castoldi, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, C. Gibson, B. Girolami, A. Giusa, H. Glu, K. Hicks, S. Hoblit, A. Honig, T. Kageya, M. Khandaker, O. C. Kistner, S. Kizilgul, S. Kucuker, A. Lapikf, A. Lehmann, P. Levi Sandri, A. Lleres, M. Lowry, M. Lucas, J. Mahon, F. Mammoliti, G. Mandaglio, M. Manganaro, L. Miceli, D. Moricciani, A. Mushkarenkovf, V. Nedorezovf, B. Norum, M. Papb, B. Preedom, H. Seyfarthb, C. Randieri, D. Rebreyend, N. Rudnevf, G. Russo, A. Sandorfi, C. Schaerf, M. L. Sperduto, H. Stroher, M. C. Sutera, C. E. Thorn, A. Turingef, V. Vegna, C. S. Whisnanth, K. Wang, X. Wei (2011)
Abstract
The extraction of resonance parameters from meson photo-reaction data is a challenging effort, that would greatly benefit from the availability of several polarization observables, measured for each reaction channel on both proton and neutron targets. In the aim of obtaining such complete experiments, polarized photon beams and targets have been developed at facilities, worldwide. We report on the latest results from the LEGS and GRAAL collaborations, providing single and double polarization measurements on pseudo-scalar meson photo-production from the nucleon.
45 Evidence for a narrow N* (1685) resonance in quasifree Compton scattering ...Cristian Randieri PhD
Evidence for a narrow N* (1685) resonance in quasifree Compton scattering on the neutron - The American Physical Society, Physical Review C, February 2011, Vol. 83, N. 2, pp. 022201-1-022201-4, ISSN: 0556-2813, doi: 10.1103/PhysRevC.83.022201
di V. Kuznetsov, M. V. Polyakov, V. Bellini, T. Boiko, S. Chebotaryov, H.-S. Dho, G. Gervino, F. Ghio, A. Giusa, A. Kim, W. Kim, F. Mammoliti, E. Milman, A. Ni, I. A. Perevalova, C. Randieri, G. Russo, M. L. Sperduto, C. M. Sutera, A. N. Vall (2011)
Abstract
The study of quasifree Compton scattering on the neutron in the energy range of Eγ=0.75–1.5 GeV is presented. The data reveal a narrow peak at W~1.685 GeV. This result, being considered in conjunction with the recent evidence for a narrow structure at W~1.68 GeV in η photoproduction on the neutron, suggests the existence of a nucleon resonance with unusual properties: a mass M~1.685GeV, a narrow width Γ⩽30 MeV, and the much stronger photoexcitation on the neutron than on the proton.
33 Measurement of beam-recoil observables Ox, Oz and target asymmetry T for t...Cristian Randieri PhD
Measurement of beam-recoil observables Ox, Oz and target asymmetry T for the reaction γρ → K+Λ - The European Physical Journal A, Hadrons and Nuclei, February 2009, Vol. 39, N. 2, pp. 149–161, ISSN: 1434-6001, doi: 10.1140/epja/i2008-10713-4
di A. Lleres, O. Bartalini, V. Bellini, J. P. Bocquet, P. Calvat, M. Capogni, L. Casano, M. Castoldi, A. D’Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, C. Gaulard, G. Gervino, F. Ghio, B. Girolami, A. Giusa, M. Guidal, E. Hourany, R. Kunne, V. Kuznetsov, A. Lapik, P. Levi Sandri, F. Mammoliti, G. Mandaglio, D. Moricciani, A. N. Mushkarenkov, V. Nedorezov, L. Nicoletti, C. Perrin, C. Randieri, D. Rebreyend, F. Renard, N. Rudnev, T. Russew, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna (2009)
Abstract
The double polarization (beam-recoil) observables Ox and Oz have been measured for the reac- tion γp → K+Λ from threshold production to E ∼ 1500MeV. The data were obtained with the linearly polarized beam of the GRAAL facility. Values for the target asymmetry T could also be extracted despite the use of an unpolarized target. Analyses of our results by two isobar models tend to confirm the necessity to include new or poorly known resonances in the 1900MeV mass region.
Introduction, Basic Principles, Terminology, Instrumentation, Ionization techniques (EI, CI, FAB, MALDI, and ESI), Mass Analyzer (Magnetic sector instruments, Quadrupole, TOF, and ICR ), and Applications of Mass Spectrometry.
DEVELOPMENT OF OPTICAL PARAMETER CALCULATIONS OF THE PROBES IN WATERDr. Ved Nath Jha
Fiber optic technology with the role of surface plasmons has tremendously advanced the sensing technique of various physical, chemical and biochemical parameters of materials. The working of the optical fiber sensor designed by us is founded on the principle of the absorption of the evanescent waves passing through the optical fiber. The technique is based on the evanescent wave penetration between two dielectric media satisfying the conditions of attenuated total internal reflections (ATR’s). In the present work, the cladding of the fiber is removed by a suitable technique, and Silver nanoparticles are deposited on it. The evanescent light waves passing out of the core of the fiber are absorbed by the metal nanoparticles. The wavelength of maximum absorption is specific to the metal nanoparticles as well as to the dielectric constant of the surrounding medium and occurs when the wavelength of evanescent light resonates with localized surface plasmon (LSP) wavelength of the nanoparticle. Noble metal nanoparticles of Silver and Gold exhibit LSP resonance in the visible region of electromagnetic spectrum. In this article, we report the characteristic parameters of three sensor probes a, b and c developed by researcher.
Laser ablation - optical cavity isotopic spectrometer (LAOCIS) for Mars roversAlexander Bolshakov
Proceedings of SPIE, v. 8385, "Sensors and Systems for Space Applications V"; Baltimore, MD, 2012. ABSTRACT: A concept of a compact device for analyzing key isotopic composition in surface materials without sample preparation is presented. This design is based on an advanced modification of Laser Induced Breakdown Spectroscopy (LIBS). First, we developed Laser Ablation Molecular Isotopic Spectrometry (LAMIS) that involves measuring isotope-resolved molecular emission, which exhibits significantly larger isotopic spectral shifts than those in atomic transitions. Second, we used laser ablation to vaporize the sample materials into a plume in which absorption spectra can be measured using a tunable diode laser. The intrinsically high spectral resolution of the diode lasers facilitates measurements of isotopic ratios. The absorption sensitivity can be boosted using cavity enhanced spectroscopy. Temporal behavior of species in a laser ablation plasma from solid samples with various isotopic composition was studied. Detection of key isotopes associated with signs of life (carbon, nitrogen, hydrogen) as well as strontium and boron in laser ablation plume was demonstrated; boron isotopes were quantified. Isotope-resolved spectra of many other molecular species were simulated. The experimental results demonstrate sensitivity to 86 Sr, 87 Sr, and 88 Sr with spectrally resolved measurements for each of them. It is possible to measure strontium isotopes in rocks on Mars for radiogenic age determination. Requirements for spectral resolution of the optical measurement system can be significantly relaxed when the isotopic abundance ratio is determined using chemometric analysis of spectra.
49 First Measurement of the Σ Beam Asymmetry in η' Photoproduction off the Pr...Cristian Randieri PhD
First Measurement of the Σ Beam Asymmetry in η' Photoproduction off the Proton near Threshold - July 2014
di P. Levi Sandri, G. Mandaglio, O. Bartalini, V. Bellini, J. P. Bocquet, M. Capogni, F. Curciarello, A. D’Angelo, V. De Leo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, C. Gaulard, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, A. Lapik, A. Lleres, F. Mammoliti, 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, V. Vegna and I. Zonta (2014)
Abstract
The Σ beam asymmetry in η' photoproduction off the proton was measured at the GRAAL polarized photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies the asymmetry as a function of the meson emission angle shows a clear structure, more pronounced at the lowest one, with a change of sign around 90°. The results are compared to the existing theories that fail to account for the data.
27 Double π0 photoproduction on the neutron at GRAAL - Physics Letters B, Jul...Cristian Randieri PhD
Double π0 photoproduction on the neutron at GRAAL - Physics Letters B, Elsevier, July 2007, Vol. 651, N. 2-3, pp. 108-113, ISSN: 0370-2693, doi: 10.1016/j.physletb.2007.06.009
di J. Ajaka, Y. Assafiri, O. Bartalini, V. Bellini, S. Bouchigny, M. Castoldi, A. D'Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, L. Fichen, G. Gervino, F. Ghio, B. Girolami, A. Giusa, M. Guidal, E. Hourany, R. Kunne, A. Lapik, P. Levi Sandri, D. Moricciani, A. Mushkarenkov, V. Nedorezov, C. Randieri, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge (2007)
Abstract
The photoproduction of double π0 on the neutron is studied in the beam energy range of 0.6 up to 1.5 GeV, using a liquid deuterium target. The cross section and the beam asymmetry are extracted and compared to those previously obtained on a proton target. The theoretical interpretation of these results is given using different models.
51 Disintegration of 12C nuclei by 700–1500 MeV photons - Nuclear Physics A,...Cristian Randieri PhD
Disintegration of 12C nuclei by 700–1500 MeV photons - Elsevier Science, Nuclear Physics A, August 2015, Vol. 940, pp. 264-278, DOI: 10.1016/j.nuclphysa.2015.05.001
di V. Nedorezov, A. D’Angelo, O. Bartalini, V. Bellini, 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, F. Mammoliti, G. Mandaglio, M. Manganaro, D. Moricciani, A. Mushkarenkov, I. Pshenichnov, C. Randieri, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M.-C. Sutera, A. Turinge, V. Vegna, I. Zonta (2015)
Abstract
Disintegration of 12C nuclei by tagged photons of 700–1500 MeV energy at the GRAAL facility has been studied by means of the LAGRANγE detector with a wide angular acceptance. The energy and momentum distributions of produced neutrons and protons as well as their multiplicity distributions were measured and compared with corresponding distributions calculated with the RELDIS model based on the intranuclear cascade and Fermi break-up models. It was found that eight fragments are created on average once per about 100 disintegration events, while a complete fragmentation of 12C into 12 nucleons is observed typically only once per 2000 events. Measured multiplicity distributions of produced fragments are well described by the model. The measured total photoabsorption cross section on 12C in the same energy range is also reported.
Boletim da missão redentorista do Amazonas no Alto juruá de outubro 2Manoel Nerys de Almeida
notícias dos missionários redentoristas e sua ação pastoral em Rodrigues Alves, Acre. Com Pe. Marino, Pe. Francisco, Ir. Eliomar e Dom Gute. Outubro de 2013.
22 η Photoproduction Off the Neutron at GRAAL: Evidence for a Resonant Struct...Cristian Randieri PhD
η Photoproduction Off the Neutron at GRAAL: Evidence for a Resonant Structure at W = 1.67 GeV - NSTAR 2004. Proceedings of Workshop on the Physics of Excited Nucleons, Grenoble (France), 24-27 March 2004. World Scientific Publishing Co. Pte. Ltd., November 2004, pp. 197-203, doi: 10.1142/9789812702272_0022
di V. Kuznetsov, O. Bartalini, V. Bellini, M. Castoldi, A D’Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, B. Girolami, A. Giusa, M. Guidal, E. Hourany, R. Kunne, A. Lapik, P. Levi Sandri, D. Moricciani, L. Nicoletti, C. Randieri, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge (2004)
Abstract
New data on η photoproduction off the neutron are presented. These data reveal a resonant structure at W=1.67 GeV.
We hear it all the time - backup your data.
And of course losing those precious memories and creations, not to mention critical business data, would be catastrophic.
But let's get specific. What advantages does backup software really offer you over simply copying files?
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.
47 Results from polarized experiments at LEGS and GRAAL - AIP Conference Proc...Cristian Randieri PhD
Results from polarized experiments at LEGS and GRAAL - The 8th International Workshop on the Physics of Excited Nucleons, NSTAR 2011, Newport News, VA, (USA) 17-20 May 2011. AIP Conference Proceedings, April 2012, Vol. 1432, pp. 56-61, ISSN: 0094-243X, doi: 10.1063/1.3701189
di A. D'Angelo, K. Ardashev, C. Bade, O. Bartalini, V. Bellini, M. Blecher, J. P. Bocquet, M. Capogni, A. Caracappa, L. E. Casano, M. Castoldi, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, C. Gibson, B. Girolami, A. Giusa, H. Glükler, K. Hicks, S. Hoblit, A. Honig, T. Kageya, M. Khandaker, O. C. Kistner, S. Kizilgul, S. Kucuker, A. Lapik, A. Lehmann, P. Levi Sandri, A. Lleres, M. Lowry, M. Lucas, J. Mahon, F. Mammoliti, G. Mandaglio, M. Manganaro, L. Miceli, D. Moricciani, A. Mushkarenkov, V. Nedorezov, B. Norum, M. Pap, B. Preedom, H. Seyfarth, C. Randieri, D. Rebreyend, N. Rudnev, G. Russo, A. Sandorfi, C. Schaerf, M. L. Sperduto, H. Ströher, M. C. Sutera, C. E. Thorn, A. Turinge, V. Vegna, C. S. Whisnant, K. Wang, X. Wei (2012)
Abstract
Compton backscattering gamma ray beams are characterized by a high degree of linear and circular polarization with low unpolarized backgrounds and have proven to provide very precise measurements of polarization observables. Latest results from LEGS and GRAAL experiments on proton and deuteron targets are presented. The Σ beam asymmetry for ω photoproduction has been measured by the GRAAL collaboration for both the ω→π0γ and the ω→π+π-π0 decay channels on the proton target; single and double polarization asymmetries have been provided also for the K photoproduction channel. E and G double polarization asymmetries for single pion photoproduction on the proton and deuteron have been measured at LEGS using a frozen spin HD target.
Miten puhua taiteellisesta tutkimuksesta tutkimuspiirien ulkopuolella? Taideyliopiston Kuvataideakatemian taiteellisen tutkimuksen professori Anita Seppä kertoi yliopistoviestinnän päivillä 3.6.2015, miten ja millaisin viestein Taideyliopiston tutkimuspaviljonki Venetsian taidebiennaalin yhteydessä kesällä 2015 jalkautui maailman tunnetuimpaan kansainvälisen taidetapahtumaan.
24 Polarization observable measurements for γp → K+Λ and γp → K+Σ for energie...Cristian Randieri PhD
Polarization observable measurements for γp → K+Λ and γp → K+Σ for energies up to 1.5 GeV - The European Physical Journal A, Hadrons and Nuclei, January 2007, Vol. 31, N. 1, pp. 73-93, ISSN: 1434-6001, doi: 10.1140/epja/i2006-10167-8
di A. Lleres, O. Bartalini, V. Bellini, J. P. Bocquet, P. Calvat, M. Capogni, L. Casano, M. Castoldi, A. D'Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, C. Gaulard, G. Gervino, F. Ghio, B. Girolami, A. Giusa, M. Guidal, E. Hourany, V. Kouznetsov, R. Kunne, A. Lapik, P. Levi Sandri, D. Moricciani, A. N. Mushkarenkov, V. Nedorezov, L. Nicoletti, C. Perrin, C. Randieri, D. Rebreyend, F. Renard, N. Rudnev, T. Russew, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge (2007)
Abstract
Beam asymmetries and hyperon recoil polarizations for the reactions γ p → K +Λ and γ p → K +Σ0 have been measured from the threshold production to 1500MeV with the GRAAL facility located at the ESRF in Grenoble. These results complement the database for the beam asymmetry, covering for the first time the production threshold region. Recent theoretical analyses are presented for which the beam asymmetry data bring interesting new information and allow to better determine some resonance parameters. Most importantly, these results strengthen the need of a new D13 state around 1900MeV.
37 Latest results from GRAAL collaboration - Chinese Physics C (HEP & NP), De...Cristian Randieri PhD
Latest results from GRAAL collaboration - Chinese Physics C (HEP & NP), December 2009, Vol. 33, N. 12, pp. 1249-1253, ISSN: 1674-1137, doi: 10.1088/1674-1137/33/12/032
di V. Vegna, V. Bellini, J. P. Bouquet, L. Casano, A. D'Angelo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, M. Guidal, E. Hourany, A. S. Ignatov, R. Kunnel, A. Lapik, A. Lleres, P. Levi Sandri, F. Mammoliti, G. Mandaglio, M. Manganaro, M. Moricciani, A.N. Mushkarenkov, V. G. Nedorezov, C. Randieri, D. Rebreyend, N. V. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge (2009)
Abstract
The GRAAL experimental set-up consists of a polarized and tagged photon beam that covers an energy range from a minimum of 600 MeV up to a maximum of 1500 MeV, of a liquid Hydrogen or Deuterium target and of the 4π Lagrange detector optimized for photon detection. It allows the study of pseudo-scalar and vector meson photoproduction on the nucleon in the energy range corresponding to the second and the third resonance regions. In the following, the σ beam asymmetries in η and π0 photoproduction on quasi-free nucleon are shown. Also single and double polarization observables in K+Λ photoproduction on free proton are shown; they are important to confirm the role of new or poorly known resonances in the 1900 MeV mass region.
35 Charged particle detection at GRAAL - Radiation Effects & Defects in Solid...Cristian Randieri PhD
Charged particle detection at GRAAL - Radiation Effects & Defects in Solids, Taylor & Francis, May June 2009, Vol. 164, N. 5-6, pp. 357-362, ISSN:1042-0150, doi: 10.1080/10420150902811698
di F. Mammoliti, V. Bellini, A. Giusa, C. Randieri, G. Russo, M. L. Sperduto, M. C. Sutera, A. D’Angelo, R. Di Salvo, A. Fantini, D. Franco, D. Moricciani, C. Schaerf, V. Vegna, P. Levi Sandri, G. Mandaglio, G. Giardina (2009)
Abstract
Experimental results on proton and charged pion detection obtained from a study of the γ+n→p+π− reaction are reported in detail. Data have been collected using the tagged and linearly polarized photon beam, impinging on a deuterium target, and the large solid angle apparatus of the GRAAL facility in Grenoble (France). The energy of the charged particles was measured using a BGO calorimeter. A comparison of the experimental data with a GEANT3-based simulation is also presented.
Investigation of the Effects of Fullerene addition and Plasma Exposure on Opt...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Polarized reflected light from the Spica binary systemSérgio Sacani
Close binary systems often show linear polarization varying
over the binary period, usually attributed to light scattered
from electrons in circumstellar clouds1–3
. One of the brightest
close binary systems is Spica (alpha Virginis) consisting of
two B-type stars orbiting with a period of just over four days.
Past observations of Spica have shown low polarization with
no evidence for variability4–6. Here we report new high-precision polarization observations of Spica that show variation
with an amplitude of about 200 parts per million. By including
polarized radiative transfer in a binary star model, we show
that the phase-dependent polarization is mainly due to light
reflected from the primary component of the binary system
off the secondary component and vice versa. The stars reflect
only a few per cent of the incident light, but the reflected light
is very highly polarized. The polarization results show that the
binary orbit is clockwise and the position angle of the line of
nodes is 130.4° ± 6.8°, in agreement with intensity interferometer results7
. We suggest that reflected light polarization
may be much more important in binary systems than has previously been recognized and may be a way of detecting previously unrecognized close binaries.
An over massive_black_hole_in_a_typical_star_forming_galaxy_2_billion_years_a...Sérgio Sacani
Uma equipe internacional de astrofísicos, liderada por Benny Trakhtenbrot, um pesquiador no Instituto para Astronomia de Zurique ETH, descobriu um gigantesco buraco negro em uma galáxia outrora normal, usando o telescópio Keck I de 10 metros de diâmetro do Observatório W. M. Keck no Havaí. A equipe, conduzindo uma pesquisa rotineira de caça por antigos e massivos buracos negros, foi surpreendida quando encontrou um com uma massa mais de 7 bilhões de vezes a massa do Sol, figurando assim entre os buracos negros mais massivos já descobertos. E pelo fato da galáxia onde ele foi descoberto ser uma galáxia típica em tamanho, o estudo levantou algumas questões sobre as premissas prévias no desenvolvimento das galáxias. As descobertas foram publicadas na revista Science.
Os dados, coletado com o novíssimo instrumento MOSFIRE do observatório Keck, revelou um gigantesco buraco negro na galáxia chamada CID-947 que está a 11 bilhões de anos-luz de distância da Terra. A incrível sensibilidade do MOSFIRE acoplada ao maior telescópio óptico/infravermelho do mundo permitiu que os cientistas pudessem observar e caracterizar esse buraco negro como ele era quando o universo tinha somente 2 bilhões de anos de vida, ou seja, apenas 14% da sua idade atual.
Ainda mais surpreendente que a massa recorde do buraco negro, foi a massa relativamente comum da galáxia que o contém.
A maior parte das galáxias abrigam buracos negros com massas de menos de 1% da massa da galáxia. Na CID 947, a massa do buraco negro é 10% da massa total da galáxia hospedeira. Devido a essa grande disparidade, a equipe deduziu que esse buraco negro cresceu tão rapidamente que a galáxia não foi capaz de pará-lo, levantando assim uma questão sobre o pensamento prévio na co-evolução de galáxias e de seus buracos negros centrais.
CHARACTERIZATION OF CRYSTALLINE AND PARTIALLY CRYSTALLINE SOLIDS BY X-RAY POWDER DIFFRACTION (XRPD)
USP <941>
Every crystalline phase of a given substance produces a characteristic X-ray diffraction pattern.
Diffraction patterns can be obtained from a randomly oriented crystalline powder composed of crystallites (crystalline regions within a particle) or crystal fragments of finite size.
Essentially three types of information can be derived from a powder diffraction pattern:
The angular position of diffraction lines (depending on geometry and size of the unit cell).
The intensities of diffraction lines (depending mainly on atom type and arrangement and preferred orientation within the sample.
Diffraction line profiles (depending on instrumental resolution, crystallite size, strain, and specimen thickness).
First M87 Event Horizon Telescope Results. IX. Detection of Near-horizon Circ...Sérgio Sacani
Event Horizon Telescope (EHT) observations have revealed a bright ring of emission around the supermassive
black hole at the center of the M87 galaxy. EHT images in linear polarization have further identified a coherent
spiral pattern around the black hole, produced from ordered magnetic fields threading the emitting plasma. Here we
present the first analysis of circular polarization using EHT data, acquired in 2017, which can potentially provide
additional insights into the magnetic fields and plasma composition near the black hole. Interferometric closure
quantities provide convincing evidence for the presence of circularly polarized emission on event-horizon scales.
We produce images of the circular polarization using both traditional and newly developed methods. All methods
find a moderate level of resolved circular polarization across the image (〈|v|〉 < 3.7%), consistent with the low
image-integrated circular polarization fraction measured by the Atacama Large Millimeter/submillimeter Array
(|vint| < 1%). Despite this broad agreement, the methods show substantial variation in the morphology of the
circularly polarized emission, indicating that our conclusions are strongly dependent on the imaging assumptions
because of the limited baseline coverage, uncertain telescope gain calibration, and weakly polarized signal. We
include this upper limit in an updated comparison to general relativistic magnetohydrodynamic simulation models.
This analysis reinforces the previously reported preference for magnetically arrested accretion flow models. We
find that most simulations naturally produce a low level of circular polarization consistent with our upper limit and
that Faraday conversion is likely the dominant production mechanism for circular polarization at 230 GHz
in M87*
.
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.
Similar to 43 Beam asymmetry Σ measurements on the π- Photoproduction off neutrons - Physical Review C, October 2010 (20)
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148 La comunicazione via satellite per la business continuity ed il disaster ...Cristian Randieri PhD
E’ ormai un dato di fatto che le moderne applicazioni IT non possono più prescindere dalla rete mediante la quale sono garantiti i collegamenti a sedi remote, i software gestionali centralizzati, la posta elettronica, le operazioni bancarie, le applicazioni CLOUD, i sistemi IoT, e così via.
147 Industria 4.0: L’automazione per l’eccellenza del settore alimentare - I ...Cristian Randieri PhD
Le PMI che rappresentano l’eccellenza per l’automazione del settore alimentare oggi si confermano come uno dei più importanti driver della ripresa del nostro Paese. Per la loro crescita effettiva restano ancora almeno due importanti gap da colmare che in sintesi sono rappresentati dai concetti innovazione tecnologica e nuove competenze, dettati dalla vera e propria rivoluzione digitale che ci sta investendo, meglio definita mediante il concetto di industria 4.0.
146 63° Congresso del CNI - Aggregazione e Comunicazione: Facciamo Rete con l...Cristian Randieri PhD
Da diverso tempo all’interno di tutti gli Ordini professionali e del CNI non si fa altro che porsi la domanda sul come trovare nuove soluzioni capaci di far superare i forti limiti dei nostri professionisti, dovuti in gran parte alle esigue dimensioni dei vari studi professionali di appartenenza, facendo leva sul concetto di aggregazione.
145 Internazionalizzazione ed innovazione: le chiavi per uscire dalla crisi c...Cristian Randieri PhD
La figura dell’Ingegnere Italiano per sostenere l’eccellenza italiana in termini di internazionalizzazione ed innovazione
La nostra professione assieme alle società d’Ingegneria Italiane rappresenta oggi potenzialmente l’eccellenza per il settore dell’Hi-Tech design & consulting, confermandosi come uno dei più importanti driver per la ripresa del nostro Paese, ma per la loro crescita effettiva restano ancora almeno due importanti gap da colmare che in sintesi sono rappresentati dai concetti di internazionalizzazione ed innovazione tecnologica dettati dalla vera e propria rivoluzione digitale che ci sta investendo, meglio definita mediante il ben noto concetto di industria 4.0. Una rivoluzione che ha un effetto dirompente non solo sull’intero settore tecnologico ma anche su tutti gli altri settori economici e della società imponendo dei cambiamenti repentini, continui e pervasivi.
144 Green Energy - Intervista a Cristian Randieri - I figli di Archimede N. 2...Cristian Randieri PhD
Il continuo ed inesorabile peggioramento delle condizioni ambientali del nostro pianeta è un indicatore palese che in questo momento l’umanità non è in condizione di avviare una politica atta ad invertire le attuali tendenze. Nonostante vi sia una provata consapevolezza e conoscenza scientifica delle modalità con cui l’essere umano modifica l’ambiente e su come tutto ciò comporti effetti negativi, disastrosi, immediati e duraturi, alla sua salute, nonostante vi siano tutti gli strumenti tecnici necessari per modificarne le cause, rimane un dato di fatto che i vari ambiti in cui i cicli virtuosi delle rinnovabili e dello sviluppo sostenibile non sono completamente ancora parte del tessuto sociale e della consapevolezza del singolo.
Die casting aluminum housing, strong and durable.
Support brightness adjustment.
Support light sensor sensitivity adjustment.
IR pass panel, delicate and covert.
IP66 waterproof.
TECHNICAL SPECIFICATIONS
LED type: 5 pieces high power 1W IR LED
Wavelength: 740nm/850nm/940nm
Beam angle: 15° to 120°
Beam distance: 70m to 10m (850nm)
Bracket: wall mount bracket
Working voltage: AC110-220V
Power consumption: <7W
Day/night switch: 0-50LUX adjustable
Brightness adjust: 5%-100% adjustable
Working temperatures: -20°C to 50°C
Protection level: IP66
Color: white
Panel: tempered glass + IR passing panel
Housing: aluminum die-casting housing
Net weight: 0.7kg
Gross weight: 0.8kg
139 Tavola Rotonda “Edge e Cloud Computing” - Automazione Oggi N. 399 – Giugn...Cristian Randieri PhD
…un vantaggio strategico per ridefinire le modalità in cui un’azienda può sviluppare i suoi servizi, fornirli ai suoi clienti e gestire in modo efficiente le sue operazioni. Ne parliamo con le aziende
Con Christian Eder, marketing director di Congatec; Giuseppe Surace, chief product & marketing officer di Eurotech; Cristian Randieri, predicente & CEO di Intellisystem Technologies (www.intellisystem.it); Alberto Griffini, product manager avanced PLC & Scada di Mitsubishi Electric; Alberto Olivini, portfolio consultant motion control di Siemens Italia; Lodovico Piermattei, consulting & solution engineer di Vertiv in Italia; Locatelli Claudio, membro del comitato scientifico SPS IPC Drives Italia.
Rfid, NFC e BLE intervengono a monte della filiera del dato, acquisendolo con peculiarità tecniche e prestazionali uniche e adattandosi al contesto dell’IoT, divenendo così la scintilla per l’interconnessione di persone, oggetti, servizi e processo
Intellisystem Technologies presenta una soluzione che utilizzando la tecnologia Rfid si pone l’obiettivo di garantire il miglioramento dei flussi logistici aziendali, facendo leva sull’eliminazione di diverse operazioni sino a oggi svolte manualmente. Il sistema denominato Logistics Rfid Scanner permette di dotare i reparti logistici di opportuni varchi elettronici intelligenti, definiti col termine ‘Gate Scanner’ che installati nei punti più nevralgici semplificano il controllo delle merci in ingresso e uscita di ogni magazzino o area di produzione.
136 Packaging: riprende la corsa delle tecnologie Made in Italy - Automazione...Cristian Randieri PhD
I costruttori italiani di macchine automatiche per il settore del packaging rafforzano la loro leadership mondiale. Sentiamo le parole di alcune aziende protagoniste
Nel settore industriale della meccanica italiana per il confezionamento e l’imballaggio, l’automazione ha una posizione strategica e un ruolo tecnologicamente importante. Abbiamo invitato alcune aziende a rispondere alle nostre domande. Abbiamo sentito: Roberto Beccalli - product manager servo & motion, South Emea di Mitsubishi Electric (http:// it3a.mitsubishielectric.com/fa/it), Michele Consoli - packaging manager di Schneider Electric (www.schneider-electric. com), Luca Nicola - product manager di Servotecnica (www.servotecnica.com), Alessandro Negri - packaging promoter di Siemens (www.siemens.it), Marco Oneglio - strategic industry manager consumer goods di Sick, Mirko Dibenedetto - product manager motion control sensors di Sick (www.sick.it), Cristian Randieri - presidente & CEO di Intellisystem Technologies (www.intellisystem.it), Elio Bolsi - general manager di Wenglor Sensoric Italiana (www.wenglor.com).
133 Tavola Rotonda “Marcia indietro" - Automazione Oggi N. 396 – Marzo 2017 -...Cristian Randieri PhD
Si chiama fenomeno ‘reshoring’ ed e la scelta delle aziende di riportare in patria il lavoro che avevano delocalizzato. Cosa ne pensano le aziende dell’automazione?
Le imprese fanno marcia indietro, una tendenza che negli ultimi anni sta prendendo piede. Si chiama fenomeno ‘reshoring’ ed è la scelta delle aziende di riportare in patria il lavoro che avevano delocalizzato. Un fenomeno nato negli USA al tempo del presidente Obama, e ben rimarcato ora da Trump, è stato anche esportato in Europa e in Italia dove la tradizione manifatturiera è antica. Sono parecchi ormai i casi di ‘rilocalizzazione produttiva’ documentati e concentrati soprattutto nel nord Italia in quei settori in cui la manifattura italiana è più attiva come la meccanica, l’abbigliamento, l’arredamento, l’agroindustria e la farmaceutica. Settori in cui ci sono competenze, esperienza, cultura d’impresa, in cui è sapiente il mix di tradizione, innovazione, qualità, impiego intelligente di conoscenze produttive tecnologiche. E soprattutto in tempi di Industry 4.0, di digital manifacturing, di start-up è sicuramente una sfida da molti punti di vista. Ne abbiamo parlato con alcuni esponenti di aziende del mondo dell’automazione per capire quanto vale il vero ‘Made in Italy’. I nostri interlocutori: Alessandra Boffa, business development manager, Robotics & Motion Division di ABB (www.abb.it); Cristian Randieri, presidente e CEO di Intellisystem Technologies (www.intellisystem.it); Marco Filippis, product manager robot di Mitsubishi Electric (http://it3a.mitsubishielectric.com/fa/it); Roberto Zuffada, head of digital enterprise team di Siemens Italia (www.siemens.it), Francesca Selva, vice president marketing & events di Messe Frankfurt Italia.
132 Soluzioni satellitari integrate per il controllo remoto dei sistemi TV Br...Cristian Randieri PhD
Le soluzioni satellitari integrate (SSI) per il monitoraggio da remoto degli apparati elettronici dei sistemi di radiodiffusione installati in aree non presidiate sviluppate da Intellisystem Technologies permettono agli operatori broadcaster di gestire in maniera sempre più efficiente la propria rete, grazie alla possibilità di conoscere in tempo reale lo stato dei propri impianti e di intervenire su essi a distanza
Ad oggi la comunicazione dati bidirezionale via satellite è l'unica in grado di garantire la trasmissione dati nei siti più remoti fornendo anche
un servizio di ridondanza implementabile in pochis-simo tempo. Tutto ciò grazie al fatto che il mondo delle connessioni dati satellitari moderne è notevolmente cambiato; sino a qualche tempo fa gli elevati costi di trasmissione ne permettevano il loro utilizzo solo per applicazioni esclusivamente militari. L'innovazione tecnologica degli ultimi anni ha consentito di migliorare nettamente le prestazioni proporzionalmente ad una notevole diminuzione dei costi di esercizio, permettendo la loro diffusione in ambiente sia industriale che professionale. Grazie alle nuove flotte di satelliti geostazionari, in orbita a circa 36.000 Km dalla Terra, i nuovi satelliti sono in grado di offrire collegamenti a Internet ad alta velocità in qualunque parte del globo, a patto che sia possibile un allacciamento del sistema a una fonte di energia. Con i recenti lanci del 2013, la connessione satellitare è diventata addirittura tecnicamente competitiva rispetto alle attuali connessioni in fibra ottica terrestri. I satelliti ricevono e inviano dati alle antenne ricetrasmittenti installate presso il cliente e li ritrasmettono a grandi infrastrutture, denominate Teleporti, connesse alle dorsali terrestri in fibra ottica. Grazie a queste ultime, è possibile estendere a largo raggio le comunicazioni internet dati e voce, offrendo servizi ad alto valore aggiunto.
131 Curarsi con la tecnologia - Il punto di vista di Intellisystem Technologi...Cristian Randieri PhD
Il mercato dell’health&care è uno dei pochi che attualmente mostra un ottimo andamento in tutto il mondo e che si sta sviluppando con una forza impressionante sia nelle economie sviluppate, sia in quelle emergenti. Negli Stati Uniti, per esempio, si stima che il settore sanitario ricopra circa un sesto dei 18.000 miliardi di dollari del PIL, con costi di gran lunga superiori a quelli di qualsiasi altro paese, specialmente per i farmaci biotech, che rappresentano la nuova frontiera di questo comparto. Anche in Europa il livello di spesa del settore ha una spiccata tendenza alla crescita dove il rapporto spesa sanitaria/PIL e del 10,3%, con alcune nazioni (Olanda, Francia, Germania) molto al disopra la media e altre (Grecia, Portogallo, Regno Unito, Italia) al di sotto. La crescita è poi dirompente in Paesi emergenti quali la Cina e nel resto dell’Asia, in America Latina e persino Africa.
130 FN 90 Febbraio 2017 - Tavola Rotonda L'analisi tanto attesa - Fieldbus & ...Cristian Randieri PhD
VEDIAMO QUI I VANTAGGI CHE SI POSSONO OTTENERE CON LA BIG DATA ANALYSIS, NONCHÉ GLI STRUMENTI A DISPOSIZIONE E LE MODALITÀ CON CUI TRASFORMARE I DATI IN DECISIONI UTILI AL BUSINESS
Abbiamo chiesto ad alcuni dei principali attori del mondo dell’automazione industriale di fare luce sull’ampio tema della big data analysis, partendo dal suo significato per conoscere poi quali applicazioni siano state messe in campo dalle aziende da loro rappresentate.
Per Cristian Randieri, presidente e CEO di Intellisystem Technologies (www.intellisystem.it), quando si parla di big data si fa riferimento a una collezione eterogenea di dati grezzi che di per sé non hanno alcun valore se non analizzati e quindi rielaborati mediante le più moderne tecniche, meglio definite col termine ‘data mining’. “Questa tecnica può essere definita come l’attività di estrazione dell’informazione da una miniera di dati grezzi. Per capire meglio questo concetto occorre approfondire il significato di alcune parole. Il dato è l’elemento base potenzialmente informativo, le cui caratteristiche sono note ma non ancora organizzate o classificate, in quanto costituito da simboli che devono essere elaborati prima di poter essere compresi. L’informazione è il risultato dell’elaborazione di più dati che restituisce una serie di dati aggregati e organizzati in modo significativo. La conoscenza è una serie di informazioni che, aggregate tra loro, consentono di diffondere sapere, comprensione, cultura o esperienza. Di conseguenza, qualsiasi operazione di big data analysis consiste in tutte le attività che hanno come obiettivo l’estrazione di informazioni da una quantità di dati indefinita, ovvero tutto ciò che attraverso ricerca, analisi e organizzazione genera sapere o conoscenza a partire da dati non strutturati. Si tratta di una serie di tecniche e metodologie molto simili alla statistica ma con una grande differenza: la prima è usata per fotografare lo stato temporale dei dati, mentre il data mining è più usato per cercare correlazioni tra variabili a scopi predittivi”.
129 Automazione e manutenzione predittiva nell’era del cloud - Automazione Og...Cristian Randieri PhD
Nell’era dei Big Data, anche per il mondo dell’automazione c’è una reale esigenza di migliorare e aggiornare i sistemi tradizionali di process data analytic integrandoli con le più recenti innovazioni tecnologiche nei settori del data mining e del machine learning. Ma per questo è opportuno rivedere alcune cose
Oggi più che mai le aziende manifatturiere posseggono un grande patrimonio informativo in termini di dati potenzialmente raccolti, derivante dagli interventi di manutenzione, dai sistemi di sensoristica applicati alle macchine. Questi dati se incrociati con altre informazioni aziendali esogene possono fornire utili indicazioni per migliorare il servizio stesso di manutenzione in termini di riduzione dei costi e dei disagi per i clienti. Non bisogna però trascurare il fatto che il trattamento di grandi moli di dati, prodotti dai molteplici sensori applicati alle macchine negli impianti produttivi, risulta un’attività complessa non solo per il volume dei dati in gioco ma anche per la loro eterogeneità e la velocità con la quale possono variare.
IL LAVORO STA CAMBIANDO VOLTO INSIEME ALL’AFFERMARSI NEL MONDO INDUSTRIALE DI CONCETTI COME INDUSTRY 4.0, DOVE CONNESSIONE E INTERATTIVITÀ SONO CONSIDERATI PUNTI NODALI: VEDIAMO I VANTAGGI DELLA ‘MOBILITY’. A cura di Ilaria De Poli. Con Alberto Griffini, product manager advanced PLC&Scada di Mitsubishi Electric, Raffaele Esposito, product manager safety I/O&networking di Phoenix Contact, Cristian Randieri, presidente e CEO di Intellisystem Technologies (www.intellisystem.it), Cristian Sartori, industrial communication product manager di Siemens Italia
124 SISTEMI DI SICUREZZA SEMPRE PIÙ “VERSO LA NUVOLA” - Safety & Security N. ...Cristian Randieri PhD
La tecnologia cloud, altrimenti nota come “nuvola informatica”, richiama un interesse sempre maggiore anche per il settore della sicurezza, nel quale le sue numerose applicazioni che spaziano dalla videosorveglianza, al controllo accessi, fino al Video Management System stanno conquistando consensi via via sempre più ampi. Al pari di molti altri tipi di applicazioni IT, anche quelle relative alla sicurezza stanno migrando sulla nuvola cercando di sfruttarne appieno tutti vantaggi offerta da questa moderna e dirompente tecnologia che nel gergo “Cloud” si traducono in: resilienza, scalabilità e semplicità di gestione.
Articolo completo disponibile alla pagina http://www.intellisystem.it/it/portfolio/ss-settembre_ottobre-2016
122 Ispezione di linee aeree - Automazione Oggi N. 393 – Ottobre 2016 - Cris...Cristian Randieri PhD
L’affidabilità del servizio ferroviario dipende dall’efficienza di sistemi
meccanici ed elettrici complessi, con migliaia di parti in movimento.
Da qui la necessità di una corretta manutenzione
Oggi sempre più compagnie ferroviarie fanno richiesta di nuovi sistemi, che siano automatici, veloci e a basso costo, per il monitoraggio e l’ispezione delle linee elettriche catenarie delle proprie reti. Una catenaria aerea è il sistema adoperato per fornire energia elettrica alla locomotiva di un treno, mediante un pantografo installato sul tetto del locomotore stesso. Tali sistemi tipicamente fanno uso di almeno due cavi: uno di supporto meccanico e un secondo di contatto, che entra appunto in contatto con le spazzole del pantografo. Il sistema è tipicamente sospeso su tralicci e sottoposto a una tensione meccanica atta a garantire la migliore aderenza con il pantografo. Una rete catenaria, di norma, è molto estesa e nella maggior parte dei casi è intensamente utilizzata, per cui è necessario che sia sempre efficiente per mantenere alta la qualità del servizio offerto.
Articolo completo disponibile alla pagina http://www.intellisystem.it/it/portfolio/ao-ottobre-2016
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
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.
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.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...
43 Beam asymmetry Σ measurements on the π- Photoproduction off neutrons - Physical Review C, October 2010
1. arXiv:1010.1715v1[nucl-ex]8Oct2010
Beam asymmetry Σ measurements on the π− photoproduction off neutrons
The Graal collaboration: G. Mandaglio1,2
, F. Mammoliti2,3
, M. Manganaro1,2
, V. Bellini2,3
, J. P.
Bocquet4
, L. Casano5
, A. D’Angelo5,6
, R. Di Salvo5
, A. Fantini5,6
, D. Franco5,6
, G. Gervino7
, F.
Ghio8
, G. Giardina1,2
, B. Girolami8
, A. Giusa2,3
, A. Ignatov9
, A. Lapik9
, P. Levi Sandri10
, A.
Lleres4
, D. Moricciani5
, A. N. Mushkarenkov9
, V. Nedorezov9
, C. Randieri2,3
, D. Rebreyend4
, N. V.
Rudnev9
, G. Russo2,3
, C. Schaerf 5,6
, M. L. Sperduto2,3
, M. C. Sutera2
, A. Turinge9
, V. Vegna5,6
.
W. J. Briscoe11
and I. I. Strakovsky11
1
Dipartimento di Fisica, Universit`a di Messina, I-98166 Messina, Italy
2
INFN, Sezione di Catania, I-95123 Catania, Italy
3
Dipartimento di Fisica e Astronomia, Universit`a di Catania, I-95123 Catania, Italy
4
LPSC, Universit´e Joseph Fourier, CNRS/IN2P3, Institut National Polytechnique de Grenoble, 38026 Grenoble, France
5
INFN, Sezione di Roma“Tor Vergata”, I-00133 Roma, Italy
6
Dipartimento di Fisica, Universit`a di Roma “Tor Vergata”, I-00133 Roma, Italy
7
Dipartimento di Fisica Sperimentale, Universit`a di Torino,
and INFN - Sezione di Torino, I-00125 Torino, Italy
8
Istituto Superiore di Sanit`a, I-00161 Roma, and INFN - Sezione di Roma, I-00185 Roma, Italy
9
Institute for Nuclear Research, RU-117312 Moscow, Russia
10
INFN-Laboratori Nazionali di Frascati, I-00044 Frascati, Italy and
11
Center for Nuclear Studies Department of Physics The George Washington University Washington, DC 20052, USA
(Dated: October 11, 2010)
The Σ beam asymmetry in the photoproduction of negative pions from quasi-free neutrons in a deu-
terium target was measured at Graal in the energy interval 700 - 1500 MeV and a wide angular range,
using polarized and tagged photons. The results are compared with recent partial wave analyses.
During the last twenty years, pseudoscalar meson pho-
toproduction has proven to be a valid and complementary
approach to hadronic reactions for the study of properties
of baryon resonances. The main disadvantage of the e.m.
probe, i.e. the lower cross section values, has been over-
come thanks to the advent of a new generation of high
duty cycle electron accelerators and to the resulting high
intensity real and virtual photon beams. These beams, in
combination with large solid angle and/or large momentum
acceptance detectors, provided recently a large amount of
high precision data.
Pseudoscalar meson photoproduction can be described
in terms of four complex CGLN[1] (or equivalently helic-
ity) amplitudes, providing seven real independent quanti-
ties for each set of incident photon energy and meson polar
angle in the CM system. To resolve the ambiguities in the
context of Barker et al. [2] it is necessary to perform a
’complete experiment’. That is eight polarization observ-
ables (including the unpolarized differential cross section)
need to be measured for each isospin channel. Waiting
for such an experiment, the analysis of meson photopro-
duction has been concentrated on a description of the re-
action mechanisms in terms of intermediate states, which
have definite parity and angular momentum and are there-
fore excited via electric and magnetic multipoles.
Polarization observables, accessible with the use of po-
larized photon beams and/or nucleon targets and/or the
measurement of the polarization of the recoil nucleon, play
a special role in the disentanglement of the hadron reso-
nances contributing to the reaction[3–7].
One further complication in the study of meson photo-
production on the nucleons comes from the isospin, which
must be conserved at the hadronic final vertex, while it can
be changed at the photon vertex.
In particular for isovector mesons, such as pions, the
transition operator can be split into an isoscalar (∆I = 0)
and isovector (∆I = 1) components, giving rise to three
independent matrix elements < If , If,z|A|Ii, Ii,z > de-
scribing the transitions between the initial and final states:
one isoscalar AIS
(with ∆I and ∆I3 = 0) and two isovec-
tor AIV
and AV 3
(∆I = 1 and ∆I3 = 0, ±1) compo-
nents.
It is necessary to perform experiments on the proton and
neutron for each final state isospin channel in order to dis-
entangle these transition amplitudes [8, 9].
Data on the four reactions (γp → π0
p, γp → π+
n,
γn → π0
n, γn → π−
p) have been collected at Graal,
with a polarized photon beam impinging on a H2 or D2 liq-
uid target and with the final products detected in a large
solid angle apparatus. This allowed for the first time the
simultaneous extraction of the beam asymmetry values of
the four reactions with the same experimental conditions
and the same photon energy range (0.55-1.5 GeV), cor-
responding to the second and third nucleon resonance re-
gions. Results for the first three reactions have already been
published by the Graal collaboration [10–12], providing for
the pion photoproduction on the nucleon a very extensive
database of high precision data which is composed of: 830
differential cross section and 437 beam asymmetry points
for π0
photoproduction on the free proton; about 300 beam
asymmetry points for π+
n photoproduction on the free pro-
ton; 216 asymmetry points for π0
photoproduction both on
2. 2
the quasi-free proton and neutron.
The last of the four reactions is the subject of the present
article. The extraction of the beam asymmetry values for
π−
p photoproduction on the quasi-free neutron advances
the isospin study of pion photoproduction on the nucleon,
constraining the determination of the three isoscalar and
isovector transition amplitudes.
EXPERIMENTAL SET-UP
The Graal γ-ray beam at the ESRF is produced by the
backward scattering in flight of laser photons on the rela-
tivistic electrons circulating in the storage ring. This tech-
nique, first used on a storage ring for the Ladon beam on
the Adone at Frascati [13], produces polarized and tagged
γ-ray beams with very high polarization and good energy
resolution. At its maximum energy the beam polarization
is very close to the one of the laser photons (linear or circu-
lar) [14] and can be easily rotated or changed with conven-
tional optical components changing the polarization of the
laser light. It remains above 74% for photon energy above
70% of its maximum. With the 6.03 GeV ESRF accelerator
and the 351 nm line of an argon (Ion) Laser, the maximum
γ-ray energy obtainable is 1487 MeV and the spectrum is
almost flat over the whole tagged spectrum. The energy
resolution of the tagged beam is limited by the optics of
the ESRF magnetic lattice and is 16 MeV (FWHM) over
the entire spectrum.
The Graal apparatus has been described in several papers
[10–12, 15–17]. A cylindrical liquid hydrogen (or deu-
terium) target is located on the beam and coaxial with it.
The detector covers the entire solid angle and is divided
into three parts. The central part, 25◦
< θ ≤ 155◦
, is cov-
ered by two cylindrical wire chambers, a Barrel made of
32 plastic scintillators and a BGO crystal ball made of 480
crystals which is well suited for the detection of γ-rays of
energy below 1.5 GeV. The chambers, the Barrel and the
BGO are all coaxial with the beam and the target. The wire
chambers detect and measure the positions and angles of
the charged particles emitted by the target while the scin-
tillating Barrel measures their energy loss. The BGO ball
detects charged and neutral particles and measures the en-
ergy deposited by them. For neutral particles it provides a
measurement of their angles by its granularity (480 crys-
tals: 15 in the θ direction and 32 in the φ direction).
At forward angles, θ ≤ 25◦
, the particles emitted from
the target encounter first two plane wire chambers which
measure their angles, then, at 3 meters from the center
of the target, two planes of plastic scintillators, made of
26 horizontal and 26 vertical bars to measure the particles
position, specific ionization and time of flight, and then a
thick (Shower Wall) wall made of a sandwich of scintilla-
tors and lead to detect charged particles, γ-rays and neu-
trons. The TOF resolution of these scintillators is of the
order of 560 ps (FWHM) for charged particles and 900 ps
for neutrons. The total thickness of the plastic scintillators
is 20 cm and the detection efficiency is about 20% for neu-
trons and 95% for γ-rays.
Backward angles, θ > 155◦
, are covered by two disks
of plastic scintillators separated by 6 mm of lead to detect
charged particles and gamma-rays escaping in the back-
ward direction.
The energy of the γ-rays is provided by the tagging set-
up which is located inside the ESRF shielding, attached to
the ESRF vacuum system. The electrons which have scat-
tered off a laser photon and produced a γ-ray have lost a
significant fraction of their energy and therefore drift away
from the equilibrium orbit of the stored electrons and fi-
nally hit the vacuum chamber of the storage ring. Before
hitting the vacuum chamber they are detected by the tag-
ging system, which measures their displacement from the
equilibrium orbit. This displacement is a measure of the
difference between their energy and that of the stored elec-
tron beam and therefore provides a measure of the energy
of the gamma-ray produced. The tagging system [11] con-
sists of 10 plastic scintillators and a 128 channels Solid
State Microstrip Detector with a pitch of 300 µm. The
plastic scintillators signals are synchronized by GaAs elec-
tronics with the RF accelerating system, and provide a tim-
ing for the entire electronics of the Graal apparatus with a
resolution of 180 ps (FWHM). This allows clear discrim-
ination between electrons coming from two adjacent elec-
tron bunches that are separated by 2.8 ns. The Microstrips
provide the position of the scattered electron and therefore
the energy of the associated gamma-ray. Their pitch (300
µm) has been set in order to limit the number of tagging
channels without appreciable reduction of the gamma-ray
energy resolution imposed by the characteristics of the stor-
age ring. The detector is located inside a shielding box
positioned in a modified section of the ring vacuum cham-
ber. The shielding box is positioned at 10 mm from the
circulating electron beam. This limits the lowest tagged
gamma-ray energy to about 550 MeV.
EVENT IDENTIFICATION AND DATA ANALYSIS
The data analysis is based on the following direct mea-
surements: the energy, Eγ, of the incident photon mea-
sured by the tagging detector; the energy, Ep, of the pro-
ton measured in the BGO or by the TOF in the forward
wall; the polar and azimuthal angles θp and φp of the pro-
ton and θπ− and φπ− of the pion measured by the pla-
nar and cylindrical MWPCs [19]. The energy of the pion,
Eπ− , is obtained by the reaction energy balance neglect-
ing the Fermi energy of the neutron in the deuterium target
(Eπ− = Eγ + Mn − Ep).
The charged particle identification in the central part of
the apparatus ( 25◦
< θ ≤155◦
) was performed using a cut
in the bi-dimensional plot of the energy lost in the barrel
versus the energy measured by the BGO calorimeter[18].
3. 3
In the forward direction (θ ≤ 25◦
) it was obtained using
the bi-dimensional cut on energy lost versus TOF measured
by the plastic scintillator wall[18]. We also applied to each
detected charged particle the condition that a coincidence
of the signals from the three charged particle detectors is
obtained.
Our simulation, based on GEANT3[20] and on a realistic
event generator[21] has shown that, with the preliminary
selection of the events obtained by the constraint that pro-
ton and pion are the only charged particles detected in the
Graal apparatus, the number of events coming from other
reaction channels is lower than 14%.
FIG. 1. (Color on line) a) the π−
-p coplanarity before (upper
curve) and after the cuts (lower curve).
The quantities measured in the Graal-experiment exceed
the number required for a full kinematical reconstruction
of the event in a (quasi-)two-body kinematics. Therefore
it is possible to calculate all kinematic variables using only
a subset of the measured ones. For example, the polar an-
gle of the pion, θcalc
π− , and the energy of the proton, Ecalc
p ,
have been calculated from the other measured quantities
and then compared with the results of their direct observa-
tions.
FIG. 2. (Color on line) difference between the Fermi momentum
reconstruction at the nth step of recursive method and at step zero
for the signal (solid line) and for the concurrent channels (dashed
line) in simulation.
Therefore the background from the other reaction chan-
nels was drastically reduced with the following constraints:
1. we reject all events with additional signals from neutral
particles in the BGO or in the Shower Wall;
2. we impose coplanarity of the p and π−
by the condition
||φπ− − φp| − 180◦
| < 3σφ, where σφ is the experimental
variance of the distribution indicated in Fig. 1;
3. we impose the condition:
x,y,z
i
(PF i − Precurs.
F i )
2
< 10 MeV/c (1)
where: PF i (i = x, y, z) is the component of the Fermi
momentum of the target nucleon calculated from the mea-
sured kinematical variables neglecting its Fermi energy;
Precurs.
F i is its value obtained at the end of a recursive pro-
cess in which at each stage the Fermi momentum is cal-
culated by inserting into the energy-momentum conserva-
tion equations the value of the Fermi energy derived by the
value of the Fermi momentum resulting from the previous
iteration. The iterations stop when the difference of the
modules of the Fermi momentum in two successive itera-
tions is less than 10 keV/c. The cut value, 10 MeV/c, was
suggested by the simulation in order to minimize the loss
of good events (see Fig. 2);
4. The last constraint is :
FIG. 3. (Color on line) the bi-dimensional distribution of ∆θ vs.
Rp as defined in this article.
(x − µx)
2
σ2
x
+
(y − µy)
2
σ2
y
−
2C(x − µx)(y − µy)
σxσy
< σ2
(2)
where x = ∆θ = θcalc
π− − θmeas
π− ; θmeas
π− is the measured
angle of the π−
while θcalc
π− is the calculated value from
the angle θp of the proton and the gamma-ray energy Eγ
provided by the tagger; y = Rp = Ecalc
p /Emeas
p , where
Emeas
p is the measured value of the proton energy and
Ecalc
p is the calculated value from Eγ and θπ− ; µx, µy, σy
and σx are the mean values and the variances obtained by a
Gaussian fit to the experimental distributions; C is the cor-
relation parameter obtained by a combined best fit of x and
4. 4
y with a bidimensional Gaussian surface(see Figs. 3). σ
has been empirically set at 3, after several attempts, to min-
imize the loss of good events and at the same time the ac-
ceptance of events from competing reactions. As a results
the contribution of spurious events is less than 2.3% as indi-
cated by the simulation. Other systematic errors arise from
our imperfect knowledge of the beam polarization due to
the Laser optics and other minor effects and do not exceed
2% in total.
The wire chambers provide the distribution of the reac-
tion vertex[19] inside the deuterium target. Fig. 4 shows
that the source of our events is well localized inside the
liquid D2.
FIG. 4. The reconstructed position of the production vertex.
To check the invariance of our results with respect to
the selection criteria in a independent analysis we have: i)
plotted alternatively ∆θ vs. ∆φ-180◦
which has the advan-
tage that the physical quantities are not correlated as shown
in Fig. 5; ii) applied an independent cut on the variable
Rp; iii) introduced a cut for PF ≤ 250 MeV/c instead of
the condition 3 - inequality (1). The results of the two pro-
cedures are consistent within one standard deviation [22].
FIG. 5. (Color on line) the bi-dimensional distribution of ∆θ vs.
∆φ − 180◦
=|φπ− − φp| − 180◦
as defined in this article.
As a further check we have plotted (see Fig. 6) the Fermi
momentum calculated for all events (spurious included)
and that calculated for the “good” events (those that have
passed our selection).
The effect of the cuts on the degree of coplanarity of the
reaction products and on the Fermi momentum is indicated
in Figs. 1 and 6 respectively.
FIG. 6. (Color on line) the Fermi momentum of the neutron
calculated before (upper curve) and after (lower curve) the cuts.
Our simulation data show that the Gaussian fit of the
difference between the Fermi momentum reconstructed by
our detectors and the one generated by using the Paris po-
tential [23] present a sigma of about 16.9 MeV/c. The cuts
provide a distribution of the Fermi momentum consistent
with our knowledge of the structure of the deuteron ex-
cluding the spurious events that would require an anoma-
lously large Fermi momentum to satisfy a quasi-two-body
kinematic. Fig. 7 compares the experimental and simu-
lated Fermi momentum distributions. For the simulation
we have used the Paris potential [23] and processed the
simulated events through the same analysis software of our
data.
FIG. 7. (Color on line) the Fermi momentum (dashed line) of the
neutron after the cuts (data) and that (solid line) generated using
the Paris potential.
5. 5
The beam polarization asymmetries have been calcu-
lated as we did in Refs. [11, 12, 16] using the symmetry
of the central detector around the beam axis. In the same
references are indicated the various checks performed to
verify the stability of our results. More than 99% of the
events that survived the cuts produce a reconstructed Fermi
momentum lower than 250 MeV/c. For this reason the re-
sults presented in Fig. 8 and in Tab. I were obtained with-
out any direct cut on the reconstructed Fermi momentum
distribution. We refer to [11] for a discussion of possible
sources of systematic errors, in particular we have shown
that we obtain the same asymmetries, in the overlapping
region, using the Green or UV laser lines. These lines pro-
duce gamma-ray beams with different spectra and polar-
izations and their comparison eliminates one main source
of systematic errors.
θcm(◦
) Eγ = 753 MeV θcm(◦
) Eγ = 820 MeV θcm(◦
) Eγ = 884 MeV θcm(◦
) Eγ = 947 MeV
35.1 0.721 ± 0.053 35.0 0.504 ± 0.046 35.2 0.431 ± 0.034 35.1 0.396 ± 0.026
52.6 0.453 ± 0.026 52.5 0.244 ± 0.015 52.5 0.219 ± 0.016 52.5 0.237 ± 0.012
67.2 0.267 ± 0.022 66.9 0.034 ± 0.014 66.9 -0.087 ± 0.017 66.7 -0.074 ± 0.017
79.3 0.106 ± 0.019 79.1 -0.173 ± 0.019 79.3 -0.369 ± 0.016 79.5 -0.534 ± 0.020
89.9 0.023 ± 0.018 90.0 -0.301 ± 0.019 90.3 -0.426 ± 0.022 90.6 -0.485 ± 0.024
104.2 -0.013 ± 0.021 104.5 -0.209 ± 0.023 104.6 -0.218 ± 0.026 105.2 -0.114 ± 0.029
127.5 -0.014 ± 0.019 127.8 -0.123 ± 0.021 127.3 -0.189 ± 0.021 127.4 -0.250 ± 0.028
148.2 -0.018 ± 0.014 148.5 -0.109 ± 0.010 148.7 -0.174 ± 0.012 149.2 -0.299 ± 0.014
162.1 -0.007 ± 0.025 162.3 -0.033 ± 0.029 162.4 -0.080 ± 0.022 162.5 -0.137 ± 0.026
θcm(◦
) Eγ = 1006 MeV θcm(◦
) Eγ = 1059 MeV θcm(◦
) Eγ = 1100 MeV θcm(◦
) Eγ = 1182 MeV
35.0 0.400 ± 0.021 34.7 0.364 ± 0.016 34.3 0.329 ± 0.017 33.8 0.297 ± 0.023
52.5 0.226 ± 0.014 52.5 0.192 ± 0.011 52.2 0.123 ± 0.011 51.1 0.083 ± 0.011
66.7 -0.112 ± 0.014 66.7 -0.185 ± 0.013 66.7 -0.253 ± 0.016 66.2 -0.292 ± 0.011
79.6 -0.577 ± 0.017 79.7 -0.676 ± 0.024 79.8 -0.636 ± 0.024 79.9 -0.642 ± 0.018
90.7 -0.447 ± 0.021 90.7 -0.429 ± 0.026 90.8 -0.406 ± 0.027 90.7 -0.388 ± 0.030
105.1 0.094 ± 0.026 104.5 0.201 ± 0.031 104.0 0.127 ± 0.039 103.2 0.149 ± 0.054
127.5 -0.248 ± 0.021 127.8 -0.201 ± 0.025 127.7 -0.133 ± 0.034 128.1 0.032 ± 0.039
149.4 -0.374 ± 0.012 149.5 -0.336 ± 0.011 149.6 -0.204 ± 0.014 149.6 0.079 ± 0.017
162.6 -0.113 ± 0.018 162.7 -0.141 ± 0.024 162.9 -0.088 ± 0.026 163.0 0.131 ± 0.031
θcm(◦
) Eγ = 1259 MeV θcm(◦
) Eγ = 1351 MeV θcm(◦
) Eγ = 1438 MeV
33.6 0.259 ± 0.013 33.2 0.253 ± 0.012 33.0 0.243 ± 0.011
50.3 0.073 ± 0.013 49.0 0.065 ± 0.008 47.6 0.045 ± 0.009
66.5 -0.280 ± 0.017 66.6 -0.236 ± 0.017 66.3 -0.152 ± 0.014
80.0 -0.493 ± 0.021 79.5 -0.318 ± 0.027 78.9 -0.156 ± 0.023
90.0 -0.255 ± 0.030 88.6 -0.074 ± 0.026 88.5 0.035 ± 0.036
102.1 -0.042 ± 0.064 102.3 0.024 ± 0.067 105.6 0.297 ± 0.100
128.4 0.238 ± 0.040 128.5 0.529 ± 0.030 127.5 0.628 ± 0.055
149.4 0.310 ± 0.017 149.5 0.476 ± 0.021 149.3 0.489 ± 0.021
163.1 0.229 ± 0.039 163.4 0.214 ± 0.026 163.4 0.264 ± 0.029
TABLE I. Beam asymmetry Σ values for photon energies Eγ ranging from 753 MeV to 1438 MeV. The errors are statistical only.
RESULTS AND DISCUSSION
In this paper, we report on the first tagged measurement
of the γn → π−
p reaction by the Graal collaboration in the
energy range from 753 MeV to 1438 MeV. The available
6. 6
1500 1750 2000 2250
c.m.,
= 128°
W (MeV)
30 60 90 120 150
E = 1438 MeV
W = 1893 MeV
30 60 90 120 150
c.m.
(degree)
E = 1351 MeV
W= 1850 MeV
30 60 90 120 150
-0.5
0.0
0.5
E =1259 MeV
W= 1802 MeV
E =1059 MeV
W= 1695 MeV
E =1182 MeV
W= 1762 MeV
E = 1100 MeV
W= 1718 MeV
-0.5
0.0
0.5
E = 1006 MeV
W= 1665 MeV
E = 947 MeV
W=1632 MeV
30 60 90 120 150
E = 884 MeV
W= 1595 MeV
30 60 90 120 150
E = 819 MeV
W=1556 MeV
30 60 90 120 150
-0.5
0.0
0.5
Exp. Data
Previous Data
MAID2007
SAID-SP09
SAID-MA09
E = 753 MeV
W= 1516 MeV
30 60 90 120 150
FIG. 8. (Color on line) The beam polarization asymmetries for γn → π−
p versus pion center-of-mass scattering angle. The photon
energy is shown. Solid (dash-dotted) lines correspond to the SAID MA09 (SP09 [26]) solution. Dotted lines give the MAID2007
[27] predictions. Experimental data are from the current (filled circles) and previous measurements[24, 25] (open circles). The plotted
points from previously published experimental data are those data points within 4 MeV of the photon energy indicated on each panel.
Plotted uncertainties are statistical. In the last panel the asymmetries are plotted versus gamma-ray energy for the CM angle of 128◦
.
The MA09 includes in its database the Graal asymmetries for the γn → π−
p and γn → π0
n[12] reactions. SP09 and MAID2007 do
not include these data.
statistics allowed the determination of the angular sigma- beam asymmetry for 11 bins in the incident-photon energy
and 9 angular bins.
Our results for the asymmetries are shown in Fig. 8 to-
gether with previous results [25] and some theoretical mod-
els. The Graal data and the results from previous untagged
measurements [25] appear to agree well in the overlapping
energies. As we have shown in Ref. [12] but also in this
analysis we have obtained the same asymmetries using in-
dependently two different set of criteria for the event selec-
tion. Moreover the close similarity between the asymme-
tries measured on the free proton (in hydrogen) and those
of quasi-free proton (in deuterium) encourages the assump-
tion that the asymmetries measured on the quasi-free neu-
tron (in deuterium) could be close to those on free neutrons.
Multipole amplitude analyses provide a powerful tool
for extracting information about the reaction process in as
nearly a model-independent manner as possible [26]. This
approach, in turn, facilitates the identification of s-channel
resonances involved in the reaction process.
SAID-MA09 is the solution that includes our results and
recent Graal results for γn → π0
n [12] in the best fit
while SAID-SP09 does not include both of them [26]. The
earlier MAID2007 solution [27] is also included in Fig. 8
for comparison. The status of the MAID database for the
MAID2007 solution is the same as for SAID-SP09. The
overall χ2
/Graal data is 483, 2634, and 8793 per 99 Graal
Σs for SAID-MA09, SAID-SP09, and MAID2007 solu-
tions, respectively.
The SAID-SP09 solution is consistent with our data in
the forward angular region where previous results con-
strained the fit. In the backward region and at energies
above 1100 MeV, the agreement becomes satisfactory only
after inclusion of our data. The MAID2007 solution agrees
with our data in the forward region. Both SAID-SP09 and
MAID2007 results exhibit structures not seen in the data
and which explain the poor χ2
for both cases.
7. 7
FIG. 9. (Color on line) Multipole amplitudes from W = 1500 to 1900 MeV for isospin 1/2. Solid (dashed) lines correspond to the real
(imaginary) part of the MA09 solution. Dashed-dot (dotted) lines give real (imaginary) part of the SP09 [26] solution. Vertical arrows
indicate the position of the considered resonance while the horizontal bars show full Γ and partial widths for ΓπN associated with the
SAID πN solution SP06 [28].
Neutron multipoles from the SAID-MA09 fit are com-
pared to the earlier SAID-SP09 determinations in Fig. 3.
Both MA09 and SP09 are quite similar, but significant dif-
ferences between them in magnitude (e.g., S11, D13, and
F15) are seen. With the addition of Graal π−
p and π0
n
asymmetries, the SAID solution is now far more reliable
than in previously published analyses.
Extending our knowledge of the asymmetry to the back-
ward directions, the results of this experiment constrain the
models in the angular region where they had the largest
variations and the major differences among themselves.
We are grateful to the ESRF as a host institution for its
hospitality and the accelerator group for the stable and reli-
able operation of the ring. We are very grateful to G. Nobili
for his competent and devoted support with the realization
and maintenance of the experimental apparatus. For their
technical support we thank: M. Iannilli, D. Pecchi, E. Tusi
and G. Vitali. WJB and IIS are supported in part by the
USDOE DE-FG02-99ER41110 Grant.
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