A. D'Angelo - Academia.edu (original) (raw)
Papers by A. D'Angelo
Electromagnetic Interactions in Nuclear and Hadron Physics - Proceedings of the International Symposium, 2002
Abstract: Neutral pion photoproduction from a liquid deuterium target was measured in the energy ... more Abstract: Neutral pion photoproduction from a liquid deuterium target was measured in the energy region near 300 MeV at the LEGS facility of Brookhaven National Laboratory. The inclusive cross sections from deuterium are in agreement with measurments from Mainz, ...
Gdh 2002: Proceedings of the Second International Symposium on the Gerasimov-Drell-Hearn Sum Rule and the Spin Structure of the Nucleon, 2003
At the GRAAL facility, a polarised and tagged {vec gamma } ray beam is produced in the energy ran... more At the GRAAL facility, a polarised and tagged {vec gamma } ray beam is produced in the energy range from 500 MeV up to 1500 MeV. Preliminary results of beam polarization asymmetries for Compton scattering on the proton are presented. These very precise measurements cover the angular range 30°-150°, providing stringent constraints to theoretical models.
Radiation Effects and Defects in Solids, 2009
Experimental results on proton and charged pion detection obtained from a study of the ??+ n??? p... more Experimental results on proton and charged pion detection obtained from a study of the ??+ n??? p+ ????? 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 ...
Nuclear Physics A, 2010
We report on the measurement of inclusive electron scattering off a carbon target performed with ... more We report on the measurement of inclusive electron scattering off a carbon target performed with CLAS at Jefferson Laboratory. A combination of three different beam energies 1.161, 2.261 and 4.461 GeV allowed us to reach an invariant mass of the final-state hadronic system W ≈ 2.4 GeV with four-momentum transfers Q 2 ranging from 0.2 to 5 (GeV/c) 2. These data, together with previous measurements of the inclusive electron scattering off proton and deuteron, which cover a similar continuous two-dimensional region of Q 2 and Bjorken variable x, permit the study of nuclear modifications of the nucleon structure. By using these, as well as other world data, we evaluated the F 2 structure function and its moments. Using an OPE-based twist expansion, we studied the Q 2-evolution of the moments, obtaining a separation of the leading-twist and the total higher-twist terms. The carbon-to-deuteron ratio of the leading-twist contributions to the F 2 moments exhibits the well known EMC effect, compatible with that discovered previously in x-space. The total higher-twist term in the carbon nucleus appears, although with large systematic uncertainties, to be smaller with respect to the deuteron case for n < 7, suggesting partial parton deconfinement in nuclear matter. We speculate that the spatial extension of the nucleon is changed when it is immersed in the nuclear medium.
The European Physical Journal A, 2005
Proceedings of XVth International Workshop on Polarized Sources, Targets, and Polarimetry — PoS(PSTP2013), 2014
The European Physical Journal A, 2007
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Czechoslovak Journal of Physics, 1999
Radiation Effects and Defects in Solids, 2009
In the framework of investigation of meson photo-production on proton and neutron in a deuterium ... more In the framework of investigation of meson photo-production on proton and neutron in a deuterium target at the GRAAL experiment, we present a method to identify the vertex of interaction when in reaction products there are at least two charged particles, by the information provided by the cylindrical multiwire proportional chambers. By this device, we are able to obtain the direction of charged particles that leave the target after a photo-production reaction. For each charged particle, the device provides the coordinates of two points in the laboratory reference system, and the z-axis represents the beam direction. We calculate the trajectory of each charged particle and its cross point, representing the vertex of the reaction.
Physical Review Letters, 2008
Acta Physica Polonica B, 2015
The workshops focus on the development of amplitude analysis tools for meson and baryon spectrosc... more The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the
Physics Letters B, 2011
We report the first, kinematically-complete measurement of the differential cross section of φmes... more We report the first, kinematically-complete measurement of the differential cross section of φmeson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, K + and K − near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections dσ dt for the initial photon energy range of 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Our finding is different from recent LEPS results on φ-meson photoproduction from deuterium in a similar incident photon energy range, but in a different momentum transfer region.
Physics Letters B, 2002
Measurement of the differential cross section for the reaction p(γ, ηp) is presented from thresho... more Measurement of the differential cross section for the reaction p(γ, ηp) is presented from threshold to 1100 MeV photon laboratory energy. The experiment has been performed using the GRAAL facility in Grenoble. For the first time, the region of the S11(1535) resonance is fully covered, allowing a precise extraction of its width. Above 900 MeV, s-wave dominance disappears while p and d-waves take over. A discussion about their origin is given, suggesting unexpected contribution from vector meson exchange or the need for "missing" resonances.
Physics Letters B, 2000
S beam asymmetries for p q photoproduction on the proton have been measured in the energy range 5... more S beam asymmetries for p q photoproduction on the proton have been measured in the energy range 550-1100 MeV over a wide angular range. The statistical and systematic errors of the data are much lower than in previous measurements, due to the high polarization of the photon beam and the cylindrical geometry of the 4p detector. Our results confirm the
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1991
Nuclear Instruments and Methods m Physics Research A305 (1991) 19-24 North-Holland 19 Taladon: a ... more Nuclear Instruments and Methods m Physics Research A305 (1991) 19-24 North-Holland 19 Taladon: a polarized and tagged gamma ray beam D. Babusci, E. Cima, M. lannarelli and E. Turri INFN, Laboratory Naztonali di Frascati, PO Box 13, I-00044 Frascati, Italy F. Basti ...
Physical Review C, 2010
The -beam asymmetry in the photoproduction of negative pions on quasi-free neutrons in a deuteriu... more The -beam asymmetry in the photoproduction of negative pions on quasi-free neutrons in a deuterium target was measured at the Grenoble Anneau Accelerateur Laser in the energy interval 700-1500 MeV and over a wide angular range, using polarized and tagged photons. Results are compared with recent partial-wave analyses.
Physical Review Letters, 2008
The analysis of the p ! 0 p reaction has been performed using data from the GRAAL experiment. The... more The analysis of the p ! 0 p reaction has been performed using data from the GRAAL experiment. The total and differential cross sections and the beam asymmetry have been obtained from threshold up to 1.5 GeV of beam energy. The two resonances S 11 1535 and 1700 are expected to be excited in the intermediate states of this reaction. The results are used to test predictions based on the assumption that both resonances are dynamically generated from the meson-baryon interaction provided by chiral Lagrangians. The term involving the 1700 excitation, followed by the decay into 1232, is found to be dominant.
Electromagnetic Interactions in Nuclear and Hadron Physics - Proceedings of the International Symposium, 2002
Abstract: Neutral pion photoproduction from a liquid deuterium target was measured in the energy ... more Abstract: Neutral pion photoproduction from a liquid deuterium target was measured in the energy region near 300 MeV at the LEGS facility of Brookhaven National Laboratory. The inclusive cross sections from deuterium are in agreement with measurments from Mainz, ...
Gdh 2002: Proceedings of the Second International Symposium on the Gerasimov-Drell-Hearn Sum Rule and the Spin Structure of the Nucleon, 2003
At the GRAAL facility, a polarised and tagged {vec gamma } ray beam is produced in the energy ran... more At the GRAAL facility, a polarised and tagged {vec gamma } ray beam is produced in the energy range from 500 MeV up to 1500 MeV. Preliminary results of beam polarization asymmetries for Compton scattering on the proton are presented. These very precise measurements cover the angular range 30°-150°, providing stringent constraints to theoretical models.
Radiation Effects and Defects in Solids, 2009
Experimental results on proton and charged pion detection obtained from a study of the ??+ n??? p... more Experimental results on proton and charged pion detection obtained from a study of the ??+ n??? p+ ????? 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 ...
Nuclear Physics A, 2010
We report on the measurement of inclusive electron scattering off a carbon target performed with ... more We report on the measurement of inclusive electron scattering off a carbon target performed with CLAS at Jefferson Laboratory. A combination of three different beam energies 1.161, 2.261 and 4.461 GeV allowed us to reach an invariant mass of the final-state hadronic system W ≈ 2.4 GeV with four-momentum transfers Q 2 ranging from 0.2 to 5 (GeV/c) 2. These data, together with previous measurements of the inclusive electron scattering off proton and deuteron, which cover a similar continuous two-dimensional region of Q 2 and Bjorken variable x, permit the study of nuclear modifications of the nucleon structure. By using these, as well as other world data, we evaluated the F 2 structure function and its moments. Using an OPE-based twist expansion, we studied the Q 2-evolution of the moments, obtaining a separation of the leading-twist and the total higher-twist terms. The carbon-to-deuteron ratio of the leading-twist contributions to the F 2 moments exhibits the well known EMC effect, compatible with that discovered previously in x-space. The total higher-twist term in the carbon nucleus appears, although with large systematic uncertainties, to be smaller with respect to the deuteron case for n < 7, suggesting partial parton deconfinement in nuclear matter. We speculate that the spatial extension of the nucleon is changed when it is immersed in the nuclear medium.
The European Physical Journal A, 2005
Proceedings of XVth International Workshop on Polarized Sources, Targets, and Polarimetry — PoS(PSTP2013), 2014
The European Physical Journal A, 2007
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Czechoslovak Journal of Physics, 1999
Radiation Effects and Defects in Solids, 2009
In the framework of investigation of meson photo-production on proton and neutron in a deuterium ... more In the framework of investigation of meson photo-production on proton and neutron in a deuterium target at the GRAAL experiment, we present a method to identify the vertex of interaction when in reaction products there are at least two charged particles, by the information provided by the cylindrical multiwire proportional chambers. By this device, we are able to obtain the direction of charged particles that leave the target after a photo-production reaction. For each charged particle, the device provides the coordinates of two points in the laboratory reference system, and the z-axis represents the beam direction. We calculate the trajectory of each charged particle and its cross point, representing the vertex of the reaction.
Physical Review Letters, 2008
Acta Physica Polonica B, 2015
The workshops focus on the development of amplitude analysis tools for meson and baryon spectrosc... more The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the
Physics Letters B, 2011
We report the first, kinematically-complete measurement of the differential cross section of φmes... more We report the first, kinematically-complete measurement of the differential cross section of φmeson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, K + and K − near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections dσ dt for the initial photon energy range of 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Our finding is different from recent LEPS results on φ-meson photoproduction from deuterium in a similar incident photon energy range, but in a different momentum transfer region.
Physics Letters B, 2002
Measurement of the differential cross section for the reaction p(γ, ηp) is presented from thresho... more Measurement of the differential cross section for the reaction p(γ, ηp) is presented from threshold to 1100 MeV photon laboratory energy. The experiment has been performed using the GRAAL facility in Grenoble. For the first time, the region of the S11(1535) resonance is fully covered, allowing a precise extraction of its width. Above 900 MeV, s-wave dominance disappears while p and d-waves take over. A discussion about their origin is given, suggesting unexpected contribution from vector meson exchange or the need for "missing" resonances.
Physics Letters B, 2000
S beam asymmetries for p q photoproduction on the proton have been measured in the energy range 5... more S beam asymmetries for p q photoproduction on the proton have been measured in the energy range 550-1100 MeV over a wide angular range. The statistical and systematic errors of the data are much lower than in previous measurements, due to the high polarization of the photon beam and the cylindrical geometry of the 4p detector. Our results confirm the
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1991
Nuclear Instruments and Methods m Physics Research A305 (1991) 19-24 North-Holland 19 Taladon: a ... more Nuclear Instruments and Methods m Physics Research A305 (1991) 19-24 North-Holland 19 Taladon: a polarized and tagged gamma ray beam D. Babusci, E. Cima, M. lannarelli and E. Turri INFN, Laboratory Naztonali di Frascati, PO Box 13, I-00044 Frascati, Italy F. Basti ...
Physical Review C, 2010
The -beam asymmetry in the photoproduction of negative pions on quasi-free neutrons in a deuteriu... more The -beam asymmetry in the photoproduction of negative pions on quasi-free neutrons in a deuterium target was measured at the Grenoble Anneau Accelerateur Laser in the energy interval 700-1500 MeV and over a wide angular range, using polarized and tagged photons. Results are compared with recent partial-wave analyses.
Physical Review Letters, 2008
The analysis of the p ! 0 p reaction has been performed using data from the GRAAL experiment. The... more The analysis of the p ! 0 p reaction has been performed using data from the GRAAL experiment. The total and differential cross sections and the beam asymmetry have been obtained from threshold up to 1.5 GeV of beam energy. The two resonances S 11 1535 and 1700 are expected to be excited in the intermediate states of this reaction. The results are used to test predictions based on the assumption that both resonances are dynamically generated from the meson-baryon interaction provided by chiral Lagrangians. The term involving the 1700 excitation, followed by the decay into 1232, is found to be dominant.