Search

Your search keyword '"L., Venturelli"' showing total 64 results
Start Over Author "L., Venturelli" Topic nuclear experiment
64 results on '"L., Venturelli"'

1. Upgrade of ASACUSA's antihydrogen detector

Author

V. Kraxberger, C. Amsler, H. Breuker, S. Chesnevskaya, G. Costantini, R. Ferragut, M. Giammarchi, A. Gligorova, G. Gosta, H. Higaki, E.D. Hunter, C. Killian, V. Kletzl, N. Kuroda, A. Lanz, M. Leali, V. Mäckel, G. Maero, C. Malbrunot, V. Mascagna, Y. Matsuda, S. Migliorati, D.J. Murtagh, Y. Nagata, A. Nanda, L. Nowak, E. Pasino, M. Romé, M.C. Simon, M. Tajima, V. Toso, S. Ulmer, L. Venturelli, A. Weiser, E. Widmann, T. Wolz, Y. Yamazaki, and J. Zmeskal

Subjects
Nuclear and High Energy Physics, Antimatter, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, FOS: Physical sciences, Data acquisition, Instrumentation and Detectors (physics.ins-det), Silicon photomultiplier, nucl-ex, High Energy Physics::Experiment, Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), Detectors and Experimental Techniques, Nuclear Experiment, Antihydrogen, Instrumentation, physics.ins-det
Abstract

The goal of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) CUSP experiment at CERN's Antiproton Decelerator is to measure the ground state hyperfine splitting of antihydrogen in order to test whether CPT invariance is broken. The ASACUSA hodoscope is a detector consisting of two layers of 32 plastic scintillator bars individually read out by two serially connected silicon photo multipliers (SiPMs) on each end. Two additional layers for position resolution along the beam axis were scintillator fibres, which will now be replaced by scintillating tiles placed onto the existing bars and also read out by SiPMs. If the antiproton of antihydrogen annihilates in the center of the hodoscope, particles (mostly pions) are produced and travel through the various layers of the detector and produce signals. The hodoscope was successfully used during the last data taking period at CERN. The necessary time resolution to discriminate between particles travelling through the detector from outside and particles produced in the center of the detector was achieved by the use of waveform digitisers and software constant fraction discrimination. The disadvantage of this readout scheme was the slow readout speed, which was improved by two orders of magnitude. This was done by omitting the digitisers and replacing them with TDCs reading out the digital time-over-threshold (ToT) signal using leading edge discrimination., Submitted to VCI2022 Proceedings in NIM A

Published
2023

2. Alignment of the CLAS12 central hybrid tracker with a Kalman Filter

Author

S.J. Paul, A. Peck, M. Arratia, Y. Gotra, V. Ziegler, R. De Vita, F. Bossù, M. Defurne, H. Atac, C. Ayerbe Gayoso, L. Baashen, N.A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, L. Biondo, A.S. Biselli, M. Bondi, S. Boiarinov, K.-Th. Brinkmann, W.J. Briscoe, W.K. Brooks, D. Bulumulla, V.D. Burkert, R. Capobianco, D.S. Carman, J.C. Carvajal, P. Chatagnon, V. Chesnokov, T. Chetry, G. Ciullo, P.L. Cole, G. Costantini, A. D’Angelo, N. Dashyan, A. Deur, S. Diehl, C. Djalali, R. Dupre, A. El Alaoui, L. El Fassi, L. Elouadrhiri, A. Filippi, K. Gates, G. Gavalian, Y. Ghandilyan, G.P. Gilfoyle, A.A. Golubenko, G. Gosta, R.W. Gothe, K. Griffioen, M. Guidal, H. Hakobyan, M. Hattawy, F. Hauenstein, T.B. Hayward, D. Heddle, A. Hobart, M. Holtrop, Y. Ilieva, D.G. Ireland, E.L. Isupov, H.S. Jo, R. Johnston, K. Joo, D. Keller, M. Khachatryan, A. Khanal, A. Kim, W. Kim, V. Klimenko, A. Kripko, L. Lanza, M. Leali, P. Lenisa, X. Li, I.J.D. MacGregor, D. Marchand, L. Marsicano, V. Mascagna, B. McKinnon, C. McLauchlin, S. Migliorati, T. Mineeva, M. Mirazita, V. Mokeev, C. Munoz Camacho, P. Nadel-Turonski, P. Naidoo, K. Neupane, D. Nguyen, S. Niccolai, M. Nicol, G. Niculescu, M. Osipenko, P. Pandey, M. Paolone, R. Paremuzyan, N. Pilleux, O. Pogorelko, M. Pokhrel, J. Poudel, J.W. Price, Y. Prok, T. Reed, M. Ripani, J. Ritman, F. Sabatié, S. Schadmand, A. Schmidt, E.V. Shirokov, U. Shrestha, P. Simmerling, D. Sokhan, N. Sparveris, M. Spreafico, I.I. Strakovsky, S. Strauch, J.A. Tan, R. Tyson, M. Ungaro, S. Vallarino, L. Venturelli, H. Voskanyan, E. Voutier, D.P. Watts, X. Wei, R. Wishart, M.H. Wood, N. Zachariou, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, data analysis method, Physics - Instrumentation and Detectors, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), CLAS, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], ddc:530, tracking detector, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Nuclear Experiment (nucl-ex), numerical calculations, Nuclear Experiment, Instrumentation, Alignment, track data analysis, Settore FIS/04, Detector, Instrumentation and Detectors (physics.ins-det), detector: alignment, Kalman filter, cosmic radiation, semiconductor detector: microstrip, performance
Abstract

International audience; Several factors can contribute to the difficulty of aligning the sensors of tracking detectors, including a large number of modules, multiple types of detector technologies, and non-linear strip patterns on the sensors. The latter two of these three factors apply to the CLAS12 CVT, which is a hybrid detector consisting of planar silicon sensors with non-parallel strips, and cylindrical micromegas sensors with longitudinal and arc-shaped strips located within a 5 T superconducting solenoid. To align this detector, we used the Kalman Alignment Algorithm, which accounts for correlations between the alignment parameters without requiring the time-consuming inversion of large matrices. This is the first time that this algorithm has been adapted for use with hybrid technologies, non-parallel strips, and curved sensors. We present the results for the first alignment of the CLAS12 CVT using straight tracks from cosmic rays and from a target with the magnetic field turned off. After running this procedure, we achieved alignment at the level of l. 967 10μm, and the widths of the residual spectra were greatly reduced. These results attest to the flexibility of this algorithm and its applicability to future use in the CLAS12 CVT and other hybrid or curved trackers, such as those proposed for the future Electron-Ion Collider.

Published
2023

3. Observation of Azimuth-Dependent Suppression of Hadron Pairs in Electron Scattering off Nuclei

Author

S J, Paul, S, Morán, M, Arratia, A, El Alaoui, H, Hakobyan, W, Brooks, M J, Amaryan, W R, Armstrong, H, Atac, L, Baashen, N A, Baltzell, L, Barion, M, Bashkanov, M, Battaglieri, I, Bedlinskiy, B, Benkel, F, Benmokhtar, A, Bianconi, L, Biondo, A S, Biselli, M, Bondi, F, Bossù, S, Boiarinov, K-Th, Brinkmann, W J, Briscoe, D, Bulumulla, V D, Burkert, R, Capobianco, D S, Carman, A, Celentano, V, Chesnokov, T, Chetry, G, Ciullo, P L, Cole, M, Contalbrigo, G, Costantini, A, D'Angelo, N, Dashyan, R, De Vita, M, Defurne, A, Deur, S, Diehl, C, Dilks, C, Djalali, R, Dupre, H, Egiyan, L, El Fassi, P, Eugenio, S, Fegan, A, Filippi, G, Gavalian, Y, Ghandilyan, G P, Gilfoyle, A A, Golubenko, G, Gosta, R W, Gothe, K A, Griffioen, M, Guidal, M, Hattawy, T B, Hayward, D, Heddle, A, Hobart, M, Holtrop, Y, Ilieva, D G, Ireland, E L, Isupov, H S, Jo, R, Johnston, K, Joo, S, Joosten, D, Keller, A, Khanal, M, Khandaker, W, Kim, A, Kripko, V, Kubarovsky, V, Lagerquist, L, Lanza, M, Leali, S, Lee, P, Lenisa, X, Li, K, Livingston, I J D, MacGregor, D, Marchand, V, Mascagna, B, McKinnon, Z E, Meziani, S, Migliorati, R G, Milner, T, Mineeva, M, Mirazita, V I, Mokeev, P, Moran, C, Munoz Camacho, K, Neupane, D, Nguyen, S, Niccolai, G, Niculescu, M, Osipenko, A I, Ostrovidov, P, Pandey, M, Paolone, L L, Pappalardo, R, Paremuzyan, E, Pasyuk, W, Phelps, N, Pilleux, D, Pocanic, O, Pogorelko, M, Pokhrel, J, Poudel, J W, Price, Y, Prok, B A, Raue, T, Reed, M, Ripani, G, Rosner, F, Sabatié, C, Salgado, A, Schmidt, R A, Schumacher, Y G, Sharabian, E V, Shirokov, U, Shrestha, P, Simmerling, D, Sokhan, N, Sparveris, S, Stepanyan, I I, Strakovsky, S, Strauch, J A, Tan, R, Tyson, M, Ungaro, S, Vallarino, L, Venturelli, H, Voskanyan, E, Voutier, X, Wei, R, Wishart, M H, Wood, N, Zachariou, Z W, Zhao, V, Ziegler, M, Zurek, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS

Subjects
nucleus: size, carbon: target, lead: target, electron nucleus: scattering, Settore FIS/04, Nuclear Theory, hadron hadron: angular correlation, General Physics and Astronomy, nucleus: yield, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], multiple scattering, angular dependence, CLAS, deuterium: target, iron: target, High Energy Physics::Experiment, hadron, electron: beam, Nuclear Experiment (nucl-ex), Nuclear Experiment, nucleus: surface, experimental results
Abstract

We present the first measurement of di-hadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets. Relative to deuterium, the nuclear yields of charged-pion pairs show a strong suppression for azimuthally opposite pairs, no suppression for azimuthally nearby pairs, and an enhancement of pairs with large invariant mass. These effects grow with increased nuclear size. The data are qualitatively described by the GiBUU model, which suggests that hadrons form near the nuclear surface and undergo multiple-scattering in nuclei. These results show that angular correlation studies can open a new way to elucidate how hadrons form and interact inside nuclei, Comment: 6 pages, 4 figures

Published
2022

4. Observation of Beam Spin Asymmetries in the Process ep→e′π+π−X with CLAS12

Author

G. Niculescu, D. Bulumulla, G. Ciullo, Aditya R. Khanal, A. El Alaoui, S. Niccolai, E. L. Isupov, D. S. Carman, F. X. Girod, Nikos Sparveris, K. A. Griffioen, D. G. Ireland, V. I. Mokeev, M. Contalbrigo, V. Crede, Nicholas Zachariou, J. C. Carvajal, Sung-Sik Lee, X. Wei, S. Boiarinov, Andrea Bianconi, P. Lenisa, C. Dilks, Fatiha Benmokhtar, O. Soto, T. B. Hayward, M. Osipenko, R. Paremuzyan, L. Marsicano, Maxime Defurne, B. A. Clary, Latifa Elouadrhiri, A. Movsisyan, N. Tyler, N. Markov, P. L. Cole, N. Dashyan, K. Hicks, I. J. D. MacGregor, S. Strauch, D. I. Glazier, V. P. Kubarovsky, Michael Paolone, Krishna Neupane, H. Hakobyan, F. Bossu, R. Tyson, J. Ritman, Eugene Pasyuk, R. De Vita, D. Marchand, H. S. Jo, H. Avakian, Eric Voutier, L. Lanza, S. Diehl, C. Salgado, A. A. Golubenko, H. Atac, H. Voskanyan, G. Costantini, W. J. Briscoe, L. Barion, S. E. Kuhn, M. Hattawy, A. Vossen, M. Guidal, A. D'Angelo, Dustin Keller, M Ehrhart, P. Naidoo, T. Chetry, D. P. Watts, P. Chatagnon, Y. Prok, U. Shrestha, Michael Wood, F. Sabatié, M. Holtrop, Chaden Djalali, L. El Fassi, V. Mascagna, G. Gavalian, K. Hafidi, A. Filippi, B. A. Raue, Luciano Pappalardo, C. Ayerbe Gayoso, I. Bedlinskiy, Michael Dugger, W. Phelps, G. Angelini, P. Rossi, K. Wei, S. Joosten, S. Fegan, M. Leali, A. Celentano, R. W. Gothe, P. Nadel-Turonski, M. Khachatryan, N. A. Baltzell, K. Livingston, Alessandro Rizzo, Axel Schmidt, T. R. O'Connell, William Brooks, I. I. Strakovsky, F. Hauenstein, A. Kim, L. Venturelli, Jie Zhang, Y. Gotra, Z. E. Meziani, A. Deur, B. Yale, E.P. Segarra, S. Nanda, A. Kripko, T. A. Forest, S. Stepanyan, Y. G. Sharabian, M. Ripani, R. Dupré, M. Bondì, M. Battaglieri, O. Pogorelko, J. Rowley, Volker D. Burkert, A. S. Biselli, A. Hobart, S. Adhikari, B. McKinnon, M. Mirazita, Gerard Gilfoyle, D. Sokhan, M. Arratia, Hovanes Egiyan, C. Munoz Camacho, M. Ungaro, K. Joo, A. Thornton, and W. Kim

Subjects
Quark, Physics, Spectrometer, Proton, Nuclear Theory, General Physics and Astronomy, Deep inelastic scattering, 01 natural sciences, Gluon, Nuclear physics, 0103 physical sciences, Cathode ray, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Beam (structure), Spin-½
Abstract

The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported for the first time. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first observation of a signal that can be used to extract the PDF $e(x)$ in a collinear framework and the helicity-dependent two-pion fragmentation function $G_1^\perp$.

Published
2021

5. Photoproduction of the f2(1270) Meson Using the CLAS Detector

Author

V. Mokeev, P. Eugenio, Vincent Mathieu, D. Heddle, R. A. Schumacher, M. Battaglieri, K. A. Griffioen, R. Paremuzyan, Laura Clark, L. Marsicano, L. Lanza, M. J. Amaryan, M Carver, G. Angelini, D. P. Watts, Gerard Gilfoyle, M. Osipenko, N. Gevorgyan, P. Lenisa, M. Contalbrigo, H. Egiyan, K. Livingston, R. Tyson, D. Sokhan, S. Stepanyan, I. J. D. MacGregor, F. X. Girod, S. Adhikari, Dustin Keller, F. Sabatié, B. McKinnon, G. Niculescu, G. Rosner, B. A. Clary, D. G. Ireland, V. Crede, D. Bulumulla, William Brooks, E. Munevar, Jie Zhang, T. B. Hayward, K. Hafidi, A. Filippi, W. Phelps, Z. E. Meziani, B. Yale, Aditya R. Khanal, L. Venturelli, M. Ehrhart, M. Khandaker, E. L. Isupov, Friedrich Klein, Alessandro Rizzo, A. Kim, Michael Paolone, S. Boiarinov, Andrea Bianconi, G. Ciullo, A. Pilloni, C. W. Kim, A. Celentano, R. W. Gothe, Y. Prok, C. E. Hyde, I. Bedlinskiy, A. El Alaoui, N. A. Baltzell, F. Bossu, T. Chetry, D. S. Carman, Nicholas Zachariou, H. S. Jo, U. Shrestha, J. C. Carvajal, H. Voskanyan, Z. W. Zhao, Fatiha Benmokhtar, Nikos Sparveris, X. Wei, W. J. Briscoe, O. Soto, V. Mascagna, Maxime Defurne, M. Holtrop, S. Joosten, S. Niccolai, D. Protopopescu, E. Voutier, Luciano Pappalardo, A. Movsisyan, R. De Vita, H. Hakobyan, O. Pogorelko, S. Strauch, J. Ritman, J. Rowley, A. I. Ostrovidov, P. Chatagnon, K. Wei, S. Diehl, C. Salgado, S. Fegan, H. Atac, Volker D. Burkert, C. Munoz Camacho, Eugene Pasyuk, A. S. Biselli, G. Gavalian, V. P. Kubarovsky, Krishna Neupane, M. Ripani, M. Hattawy, K. Hicks, N. Dashyan, Michael Dugger, Yordanka Ilieva, L. Barion, Barry Ritchie, R. Dupre, D. Marchand, M. Ungaro, G. V. Fedotov, Q. Huang, K. P. Adhikari, K. Joo, D. G. Jenkins, M. Leali, Axel Schmidt, I. I. Strakovsky, P. Nadel-Turonski, A. Deur, Mark W. Bondi, M. E. McCracken, N. Tyler, C. Djalali, A. D'Angelo, L. El Fassi, A. Kripko, Y. G. Sharabian, and P. L. Cole

Subjects
Quark, Physics, Spectrometer, Meson, High Energy Physics::Lattice, Nuclear Theory, Quark model, Detector, General Physics and Astronomy, Quantum number, 01 natural sciences, 7. Clean energy, Resonance (particle physics), Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics
Abstract

The quark structure of the f2(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq¯) resonance with quantum numbers JPC=2++. Recently, it was proposed that the f2(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π+π-, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction γp→π0π0p, using the CEBAF Large Acceptance Spectrometer detector at Jefferson Lab for incident beam energies between 3.6 and 5.4 GeV. Differential cross sections, dσ/dt, for f2(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations.

Published
2021

6. Beam Spin Asymmetry in Semi-Inclusive Electroproduction of Hadron Pairs

Author

K. Park, V. P. Kubarovsky, Krishna Neupane, C. W. Kim, H. Avakian, H. Voskanyan, W. J. Briscoe, Dustin Keller, P. Eugenio, Michael Wood, K. Hafidi, G. Gavalian, L. Marsicano, A Hobart, V. Mokeev, F. X. Girod, R. A. Schumacher, M. Battaglieri, I. I. Strakovsky, R. W. Gothe, T. Chetry, M. J. Amaryan, F. Sabatié, K. Wei, S. Fegan, N. Markov, L. Guo, Alessandro Rizzo, K. A. Griffioen, Fatiha Benmokhtar, Gerard Gilfoyle, R. Paremuzyan, E. L. Isupov, A. Deur, S. Pisano, V. Crede, Ross Milner, O. Soto, P. Lenisa, M. Contalbrigo, C. Dilks, L. Lanza, M. Ungaro, T. A. Forest, C. Mullen, W. K. Brooks, M. Guidal, Z. W. Zhao, S. Stepanyan, N. A. Baltzell, M. Holtrop, T. B. Hayward, Friedrich Klein, Andrea Celentano, O. Pogorelko, J. Poudel, A. Filippi, Brian Raue, K. Hicks, K. Joo, D. Marchand, M. Osipenko, Luciano Pappalardo, K. L. Giovanetti, Hovanes Egiyan, M. Ripani, C. Munoz Camacho, A. D'Angelo, B. Yale, S. Adhikari, L. Venturelli, B. McKinnon, M. Ehrhart, D. G. Ireland, Tim O'Connell, I. Bedlinskiy, D. I. Glazier, W. Phelps, D. G. Jenkins, N. Tyler, M. Leali, L. El Fassi, C. Djalali, Volker D. Burkert, W. Kim, T. Mineeva, D. Heddle, R. De Vita, G. Ciullo, V. Mascagna, H. S. Jo, A. S. Biselli, M. Mirazita, D. Bulumulla, Y. Prok, D. S. Carman, G. Niculescu, B. S. Ishkhanov, E. Pasyuk, Aditya R. Khanal, X. Wei, R. G. Fersch, Andrea Bianconi, H. Atac, P. L. Cole, N. Dashyan, G. Angelini, P. Chatagnon, B. A. Clary, P. Rossi, M. Defurne, Michael Paolone, L. Barion, Axel Schmidt, Aurore Courtoy, K. Livingston, M. Khandaker, Jie Zhang, I. J. D. MacGregor, E. Golovatch, R. Dupre, Y. Ghandilyan, Q. Huang, E. Voutier, A. Vossen, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, J. C. Carvajal, S. Strauch, D. P. Watts, F. Bossu, Nikolaos Sparveris, Dinko Pocanic, S. E. Kuhn, M. Hattawy, Y. G. Sharabian, S. Boiarinov, H. Hakobyan, J. Ritman, S. Diehl, C. Salgado, U. Shrestha, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS

Subjects
High Energy Physics::Lattice, Nuclear Theory, Hadron, parton: distribution function, General Physics and Astronomy, Parton, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Economica, higher-twist, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), electron: beam, Nuclear Experiment, dimension: 1, Physics, Quantum chromodynamics, deep inelastic scattering: semi-inclusive reaction, Settore FIS/04, nucleon, kinematics, Quarks and Gluons, helicity distributions, quark: valence, Nucleon, Jefferson Lab, Quark, Particle physics, polarization: longitudinal, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Transversity Distributions, hadron: electroproduction, hadron: pair production, Pion, CLAS, Hadron Physics, quantum chromodynamics, 0103 physical sciences, ddc:530, 010306 general physics, High Energy Physics::Phenomenology, Ambientale, Deep inelastic scattering, spin: asymmetry: measured, Distribution function, Elementary Particles and Fields, QCD Dynamics, High Energy Physics::Experiment, pi: pair production, experimental results
Abstract

Physical review letters 126(6), 062002 (2021). doi:10.1103/PhysRevLett.126.062002, Published by APS, College Park, Md.

Published
2021

7. An experimental program with high duty-cycle polarized and unpolarized positron beams at Jefferson Lab

Author

Anthony W. Thomas, M. Battaglieri, R. De Vita, D. Marchand, Latifa Elouadrhiri, S. Habet, Hubert Spiesberger, P. Gueye, David Hamilton, Giovanni Salmè, A. Filippi, Pete Markowitz, D. Perera, G. Kalicy, M. Muhoza, N. Kalantarians, H. Atac, M. Khandaker, J. Xie, F. Sabatié, M. Mazouz, Ashot Gasparian, I.P. Fernando, V. Klimenko, T. A. Forest, D. McNulty, Z. E. Meziani, M. Boer, M. McCaughan, A. Asaturyan, J. P. Chen, V. Kozhuharov, S. Stepanyan, Simonetta Liuti, T. Patel, Alberto Accardi, M. Spata, Andrew Puckett, Andreas Metz, Salina Ali, V. Bellini, L. Barion, V. V. Berdnikov, Alexandre Camsonne, P. E. Reimer, M. Shabestari, P. Bisio, Simon Širca, T. Averett, J. Kim, Nikolaos Sparveris, M. Poelker, M. Spreafico, H. F. Ibrahim, Dipangkar Dutta, V. Bertone, Bogdan Wojtsekhowski, Ross Milner, H. Avakian, C. E. Hyde, P. M. King, Marc Vanderhaeghen, A. Somov, Yulia Furletova, Miha Mihovilovič, V. Tadevosyan, P. Sznajder, S. Migliorati, R. S. Beminiwattha, T. Chetry, M. Guidal, Olfred Hansen, T. Kutz, Z. W. Zhao, Barbara Pasquini, Eric Voutier, L. Lanza, M. J. Amaryan, J. R. M. Annand, Fatiha Benmokhtar, T. Gautam, H. Voskanyan, Richard Trotta, Ian L. Pegg, J. F. Owens, W. J. Briscoe, Jingyi Zhou, P. Valente, M. N. H. Rashad, Gordan Krnjaic, P. Lenisa, Elena Santopinto, Joseph Grames, M. Leali, S. Zhamkochyan, M. Caudron, Kai-Thomas Brinkmann, Elton Smith, L. Marsicano, Andrei Afanasev, Luciano Pappalardo, M. Carmignotto, Donal Day, L. Venturelli, Eugene Pasyuk, M. Ungaro, C. Peng, L. Causse, D. Hasell, G. Costantini, Douglas Higinbotham, N. D’Hose, J. Murphy, P. Chatagnon, R. Dupré, M. Bondì, Alexander Ilyichev, Matteo Rinaldi, P. Stoler, Brian Raue, G. N. Grauvogel, R. Santos Estrada, Kondo Gnanvo, K. Price, Q. Liu, S. Diehl, J. Nazeer, Y. G. Sharabian, X. Zheng, S. Niccolai, P. G. Blunden, J. Arrington, Riad Suleiman, J. Erler, S. Joosten, Andrea Bianconi, H.-S. Ko, P. L. Cole, Nilanga Liyanage, I. Albayrak, K. Joo, Jan C. Bernauer, F.-X. Girod, D. Gaskell, A. Kim, Juliette Mammei, A. Italiano, M. Hattawy, C. Ayerbe Gayoso, I. I. Strakovsky, M. Yurov, N. Randazzo, A. Deur, Wally Melnitchouk, H.-G. Zaunick, Michael Kohl, A. D'Angelo, E. Nardi, M. Paolone, C. Zorn, L. El Fassi, B. T. Kriesten, L. Darmé, M. Rathnayake, A. Shahinyan, Jie Zhang, Alessandro Rizzo, D. Flay, W. Xiong, H. Dutrieux, V. Sergeyeva, S. Zhang, E. R. Kinney, Hervé Moutarde, B. Dongwi, Axel Schmidt, Rolf Ent, S. Zhao, Volker D. Burkert, A. S. Tadepalli, A. S. Biselli, Tanja Horn, G. Niculescu, T. Cao, A. Celentano, P. Nadel-Turonski, Ethan Cline, J. Roche, B. Karky, M. Contalbrigo, H. Szumila-Vance, S. Fucini, O. Rondon-Aramayo, M. De Napoli, V. Mascagna, E. Fuchey, L. Cardman, G. Ciullo, Haiyan Gao, Cynthia Keppel, M. Ehrhart, A. Movsisyan, R. Novotny, A. Hobart, Sergio Scopetta, B. McKinnon, S. A. Wood, H. Mkrtchyan, M. Tiefenback, C. Munoz Camacho, Xinzhan Bai, R. Paremuzyan, B. Sawatzky, D. Sokhan, M. Suresh, Markus Diefenthaler, Z. Ye, Mauro Raggi, M. Kerver, Y. Roblin, A. Mkrtchyan, V. P. Kubarovsky, R. Capobianco, T. J. Hague, Dustin Keller, Sonny Mantry, Vladimir Khachatryan, Peter Schweitzer, Michael Wood, Maxime Defurne, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
cross-section, ratio, Photon, parton distributions, elastic scattering, Parton, polarized beam, Electron, Leptons Accelerators, Structure of Nucleons, 7. Clean energy, 01 natural sciences, Dark photon, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Positron, Economica, electromagnetic form-factors, virtual compton-scattering, generalized, squared 4-momentum transfers, lepton-flavor, violation, electron-proton, parity violation, pair production, Physics, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, Elastic scattering, Dark sector, JLab, dark photon, Settore FIS/04, lepton: flavor: violation, nucleon: generalized parton distribution, 3. Good health, High Energy Physics - Phenomenology, Elastic and deep inelastic Scattering, Nucleon, Jefferson Lab, Nuclear and High Energy Physics, nucleon: form factor: electromagnetic, FOS: Physical sciences, Socio-culturale, helium: target, Context (language use), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, PE2_2, PE2_1, deeply virtual Compton scattering, 0103 physical sciences, quantum chromodynamics, 010306 general physics, PE2_3, activity report, exchange: two-photon, electroweak interaction, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Ambientale, positron: beam, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], charge: asymmetry, Positron Beams, Physics::Accelerator Physics, proposal, High Energy Physics::Experiment
Abstract

Positron beams, both polarized and unpolarized, are identified as essential ingredients for the experimental programs at the next generation of lepton accelerators. In the context of the hadronic physics program at Jefferson Lab (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of nucleons and nuclei, in both the elastic and deep-inelastic regimes. For instance, elastic scattering of polarized and unpolarized electrons and positrons from the nucleon enables a model independent determination of its electromagnetic form factors. Also, the deeply-virtual scattering of polarized and unpolarized electrons and positrons allows unambiguous separation of the different contributions to the cross section of the lepto-production of photons and of lepton-pairs, enabling an accurate determination of the nucleons and nuclei generalized parton distributions, and providing an access to the gravitational form factors. Furthermore, positron beams offer the possibility of alternative tests of the Standard Model of particle physics through the search of a dark photon, the precise measurement of electroweak couplings, and the investigation of charged lepton flavor violation. This document discusses the perspectives of an experimental program with high duty-cycle positron beams at JLab., Comment: 18 pages, 7 figures This version superseeds the previous version which scientific content was decomposed into several more elaborated articles. All of these articles will be collected in the EPJ A Topical Issue about "Positron beam and physics at Jefferson Lab (e+@Jlab)"

Published
2021

8. Measurement of the proton spin structure at long distances

Author

P. Eugenio, J. Brock, N. Dashyan, I. Bedlinskiy, S. Choi, P. Nadel-Turonski, A. Hobart, M. Defurne, S. E. Kuhn, Latifa Elouadrhiri, P. Chatagnon, M. Ripani, C. D. Keith, D. Bulumulla, Aditya R. Khanal, S. Adhikari, B. McKinnon, T. Holmstrom, V. Mokeev, G. V. Fedotov, H. S. Jo, L. Guo, Alessandro Rizzo, Andrea Bianconi, L. Barion, M. Mirazita, K. Livingston, M. Hattawy, N. Markov, G. Rosner, Simon Širca, S. Fegan, Y. Ghandilyan, Jie Zhang, P. Bosted, Michael Paolone, C. Carlin, M. Guidal, M. L. Seely, E. Pasyuk, D. P. Watts, F. Bossu, Laura Clark, S. Niccolai, N. Guler, M. Holtrop, B. Yale, R. A. Schumacher, P. Rossi, W. Phelps, V. Mascagna, S. Joosten, Axel Schmidt, Alexandre Deur, Luciano Pappalardo, Nikolaos Sparveris, V. Crede, I. I. Strakovsky, W. Kim, Fatiha Benmokhtar, M. Ehrhart, D. I. Glazier, V. P. Kubarovsky, T. A. Forest, O. Pogorelko, Z. W. Zhao, J. Rowley, S. Stepanyan, A. I. Ostrovidov, K. Park, Krishna Neupane, R. De Vita, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, D. G. Ireland, C. W. Kim, H. Avakian, C. Mullen, W. K. Brooks, A. Kripko, Andrea Celentano, Volker D. Burkert, A. S. Biselli, J. C. Carvajal, V. Sulkosky, H. Atac, Karl Slifer, M. Leali, F. Sabatié, L. Venturelli, Y. G. Sharabian, X. Zheng, M. Bondì, H. Voskanyan, P. Lenisa, W. J. Briscoe, I. J. D. MacGregor, M. Contalbrigo, S. K. Phillips, T. Mineeva, T. B. Hayward, Friedrich Klein, Brian Raue, J. Poudel, N. Tyler, C. Djalali, G. Ciullo, M. Osipenko, Y. Prok, D. S. Carman, X. Wei, K. A. Griffioen, E. Voutier, Dustin Keller, S. Strauch, L. Lanza, R. W. Gothe, Michael Wood, T. Chetry, K. Hafidi, R. Dupre, M. Battaglieri, Gerard Gilfoyle, E. L. Isupov, V. A. Drozdov, S. Boiarinov, H. Kang, U. Shrestha, F.-X. Girod, K. P. Adhikari, H. Hakobyan, J. Ritman, S. Diehl, C. Salgado, R. G. Fersch, M. Ungaro, E. Long, J. P. Chen, D. Heddle, P. L. Cole, D. G. Meekins, A. D'Angelo, K. Hicks, L. El Fassi, K. Joo, M. Khandaker, M. J. Amaryan, A. Filippi, K. L. Giovanetti, Larry Weinstein, L. Marsicano, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS

Subjects
polarizabilities, Photon, Proton, High Energy Physics::Lattice, Nuclear Theory, General Physics and Astronomy, polarized target, polarized beam, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, High Energy Physics - Experiment, Theoretical Nuclear Physics, Experimental Nuclear Physics, High Energy Physics - Experiment (hep-ex), effective field theory, Economica, Proton spin crisis, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Experimental particle Physics, order, Nuclear Experiment (nucl-ex), Nuclear Experiment, Spin-½, Quantum chromodynamics, Physics, Settore FIS/04, nucleon, virtual compton-scattering, chiral perturbation-theory, sum-rule, moments, evolution, sum rule, kinematics, Quantum electrodynamics, nuclear matter, Nucleon, nucleon: structure, Strong interaction, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], p: spin, PE2_2, momentum transfer: low, PE2_1, CLAS, 0103 physical sciences, quantum chromodynamics, ddc:530, 010306 general physics, PE2_3, quark gluon, Coupling constant, nuclear force, scattering, Ambientale, Physics::Accelerator Physics, nucleon: spin, High Energy Physics::Experiment, experimental results
Abstract

Measuring the spin structure of protons and neutrons tests our understanding of how they arise from quarks and gluons, the fundamental building blocks of nuclear matter. At long distances the coupling constant of the strong interaction becomes large, requiring non-perturbative methods to calculate quantum chromodynamics processes, such as lattice gauge theory or effective field theories. Here we report proton spin structure measurements from scattering a polarized electron beam off polarized protons. The spin-dependent cross-sections were measured at large distances, corresponding to the region of low momentum transfer squared between 0.012 and 1.0 GeV$^2$. This kinematic range provides unique tests of chiral effective field theory predictions. Our results show that a complete description of the nucleon spin remains elusive, and call for further theoretical works, e.g. in lattice quantum chromodynamics. Finally, our data extrapolated to the photon point agree with the Gerasimov-Drell-Hearn sum rule, a fundamental prediction of quantum field theory that relates the anomalous magnetic moment of the proton to its integrated spin-dependent cross-sections., Published version. 10 pages, 5 figures. 20 pages of supplementary material (data tables and a figure)

Published
2021

9. Photoproduction of η mesons off the proton for 1.2<Eγ<4.7GeV using CLAS at Jefferson Laboratory

Author

I. Illari, R. A. Schumacher, U. Shrestha, M. Leali, S. Adhikari, B. McKinnon, C. A. Meyer, E. Munevar, P. Chatagnon, B. S. Ishkhanov, Aditya R. Khanal, G. V. Fedotov, P. Lenisa, J. Ritman, S. Stepanyan, N. Dashyan, D. P. Watts, Andrea Bianconi, M. Ungaro, K. P. Adhikari, A. El Alaoui, I. I. Strakovsky, G. Rosner, T. Chetry, A. Deur, C. W. Kim, Laura Clark, W. Phelps, M. Battaglieri, Nicholas Zachariou, J. C. Carvajal, Alexander Schmidt, M. J. Amaryan, William Brooks, Yordanka Ilieva, T. B. Hayward, V. Mascagna, B. A. Clary, E. L. Isupov, Y. G. Sharabian, H. Voskanyan, Friedrich Klein, W. J. Briscoe, P. Eugenio, S. Boiarinov, Brian Raue, G. Angelini, L. Barion, K. Joo, M. Guidal, Michael Paolone, Z. W. Zhao, F. X. Girod, F. Bossu, R. Cruz-Torres, E. Golovatch, M. Holtrop, R. Dupre, S. Strauch, Hovanes Egiyan, Maxime Defurne, K. A. Griffioen, Dustin Keller, C. Munoz Camacho, H. Hakobyan, Y. Prok, H. S. Jo, M. Hattawy, Michael Wood, K. Hafidi, D. G. Ireland, Luciano Pappalardo, V. Crede, A. Kim, D. I. Glazier, G. Ciullo, D. S. Carman, F. Sabatié, T. Hu, R. Paremuzyan, R. De Vita, D. Marchand, D. Protopopescu, Eugene Pasyuk, X. Wei, L. Venturelli, S. Diehl, Fatiha Benmokhtar, O. Soto, C. Salgado, E. Voutier, L. Lanza, Nicholas M. Harrison, Gerard Gilfoyle, A. Filippi, A. Movsisyan, J. W. Price, D. Sokhan, V. P. Kubarovsky, I. Bedlinskiy, M. Khandaker, M. Khachatryan, Nikolaos Sparveris, Z. E. Meziani, K. Wei, S. Niccolai, K. Livingston, N. Markov, Iu. Skorodumina, N. Tyler, C. Djalali, J. A. Tan, V. I. Mokeev, D. Heddle, Jie Zhang, G. Gavalian, D. G. Jenkins, R. Fersch, M. Ehrhart, M. Ripani, O. Pogorelko, P. L. Cole, J. Rowley, Tim O'Connell, A. I. Ostrovidov, Michael Dugger, T. Mineeva, P. Nadel-Turonski, H. Atac, A. S. Biselli, A. D'Angelo, L. Guo, Sylvester Joosten, Alessandro Rizzo, G. Asryan, L. El Fassi, C. Ayerbe Gayoso, M. E. McCracken, A. Hobart, C. Hanretty, W. Kim, G. Niculescu, P. Stoler, M. Osipenko, I. J. D. MacGregor, K. Hicks, M. Contalbrigo, J. Poudel, Z. Akbar, A. Celentano, and R. W. Gothe

Subjects
Physics, Particle physics, Range (particle radiation), Photon, Proton, Meson, 010308 nuclear & particles physics, Sigma, Photon energy, 01 natural sciences, 7. Clean energy, Resonance (particle physics), 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Photoproduction cross sections are reported for the reaction $\gamma p\to p\eta$ using energy-tagged photons and the CLAS spectrometer at Jefferson Laboratory. The $\eta$ mesons are detected in their dominant charged decay mode, $\eta\to \pi^+\pi^-\pi^0$, and results on differential cross sections are presented for incident photon energies between 1.2 and 4.7 GeV. These new $\eta$ photoproduction data are consistent with earlier CLAS results but extend the energy range beyond the nucleon resonance region into the Regge regime. The normalized angular distributions are compared with the experimental results from several other experiments, and with predictions of $\eta$ MAID\,2018 and the latest solution of the Bonn-Gatchina coupled-channel analysis. Differential cross sections $d\sigma/dt$ are presented for incident photon energies $E_\gamma > 2.9$ GeV ($W > 2.5$ GeV), and compared with predictions which are based on Regge trajectories exchange in the $t$-channel (Regge models). The data confirm the expected dominance of $\rho$, $\omega$ vector-meson exchange in an analysis by the Joint Physics Analysis Center.

Published
2020

10. Extraction of beam-spin asymmetries from the hard exclusive π+ channel off protons in a wide range of kinematics

Author

Y. G. Sharabian, K. Tezgin, S. E. Kuhn, M. Hattawy, S. Adhikari, M. Khachatryan, M. J. Amaryan, N. Tyler, P. Lenisa, C. Dilks, J. A. Tan, C. W. Kim, H. Avakian, B. McKinnon, Maxime Defurne, Laura Clark, K. A. Griffioen, Chaden Djalali, D. Bulumulla, T. Mineeva, L. Guo, G. Angelini, D. I. Glazier, B. S. Ishkhanov, S. Strauch, Aditya R. Khanal, F. X. Girod, T. B. Hayward, M. Guidal, D. P. Watts, K. L. Giovanetti, P. L. Cole, E. L. Isupov, E. Golovatch, G. Asryan, L. Lanza, R. De Vita, Alessandro Rizzo, Z. W. Zhao, V. Crede, R. Dupre, H. Voskanyan, Andrea Bianconi, N. Markov, Brian Raue, Y. Ghandilyan, S. Boiarinov, A. D'Angelo, M. Mirazita, M. Ehrhart, W. Phelps, W. J. Briscoe, A. Filippi, M. Holtrop, Victor Mokeev, U. Shrestha, L. El Fassi, H. Atac, P. Nadel-Turonski, M. Khandaker, Luciano Pappalardo, P. Eugenio, J. W. Price, O. Pogorelko, I. J. D. MacGregor, T. Chetry, M. Osipenko, J. Rowley, M. Ripani, Fatiha Benmokhtar, H. Hakobyan, O. Soto, M. Battaglieri, S. Diehl, Paolo Rossi, K. Park, Michael Paolone, A. Celentano, R. W. Gothe, D. Heddle, F. Bossu, D. G. Ireland, Hovanes Egiyan, C. Munoz Camacho, W. Kim, Axel Schmidt, G. Niculescu, P. Stoler, Volker D. Burkert, M. Contalbrigo, A. S. Biselli, M. Ungaro, I. I. Strakovsky, K. Hicks, A. Deur, Nicholas M. Harrison, Gerard Gilfoyle, D. Marchand, V. Mascagna, Eugene Pasyuk, W. K. Brooks, D. G. Jenkins, S. Joosten, L. Marsicano, V. P. Kubarovsky, K. P. Adhikari, M. Leali, D. Riser, Z. E. Meziani, Y. Prok, F. Sabatié, I. Bedlinskiy, P. Kroll, K. Joo, Dustin Keller, Michael Wood, A. Kim, K. Livingston, Jie Zhang, H. S. Jo, C. Salgado, A. El Alaoui, Y. Ilieva, P. Chatagnon, Nicholas Zachariou, J. C. Carvajal, K. Semenov-Tian-Shansky, N. Dashyan, E. Voutier, L. Venturelli, L. Barion, R. A. Schumacher, G. Ciullo, D. S. Carman, Nikos Sparveris, X. Wei, T. A. Forest, S. Stepanyan, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS

Subjects
Particle physics, generalized parton distribution, Partons, Nucleons, Compton Scattering, media_common.quotation_subject, General Physics and Astronomy, parton: distribution function, Socio-culturale, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Resonance (particle physics), Asymmetry, High Energy Physics - Experiment, Pion, PE2_2, PE2_1, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], 010306 general physics, Nuclear Experiment, PE2_3, Spin-½, media_common, Physics, Settore FIS/04, electroproduction, moment, Moment (mathematics), distribution amplitude, High Energy Physics - Phenomenology, Amplitude, kinematics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Elementary Particles and Fields, High Energy Physics::Experiment, Center of mass, asymmetry, experimental results
Abstract

We have measured beam-spin asymmetries to extract the \ud sin\ud ϕ\ud moment \ud A\ud sin\ud ϕ\ud L\ud U\ud from the hard exclusive \ud →\ud e\ud p\ud →\ud e\ud ′\ud n\ud π\ud +\ud reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The \ud A\ud sin\ud ϕ\ud L\ud U\ud moment has been measured up to \ud 6.6\ud \ud \ud GeV\ud 2\ud in \ud −\ud t\ud , covering the kinematic regimes of generalized parton distributions (GPD) and baryon-to-meson transition distribution amplitudes (TDA) at the same time. The experimental results in very forward kinematics demonstrate the sensitivity to chiral-odd and chiral-even GPDs. In very backward kinematics where the TDA framework is applicable, we found \ud A\ud sin\ud ϕ\ud L\ud U\ud to be negative, while a sign change was observed near 90° in the center of mass. The unique results presented in this Letter will provide critical constraints to establish reaction mechanisms that can help to further develop the GPD and TDA frameworks.

Published
2020

11. First measurement of direct photoproduction of the a2(1320)0 meson on the proton

Author

J. Rowley, A. I. Ostrovidov, Volker D. Burkert, A. S. Biselli, W. Phelps, K. A. Griffioen, V. Mascagna, N. Markov, M. E. McCracken, A. Hobart, Carlos A. Salgado, A. Filippi, A. Pilloni, Frank Klein, Dustin Keller, P. Eugenio, L. Marsicano, Sylvester Joosten, Maxime Defurne, M. Khandaker, M. Khachatryan, M. Osipenko, Pawel Nadel-Turonski, Michael Paolone, Alexander Schmidt, D. I. Glazier, D. Bulumulla, E. Munevar, B. S. Ishkhanov, Aditya R. Khanal, Nikolaos Sparveris, M. Ungaro, K. Hafidi, F. Bossu, M. Guidal, G. Niculescu, L. Lanza, D. G. Jenkins, I. J. D. MacGregor, R. De Vita, M. Leali, Laura Clark, M. J. Amaryan, Andrea Bianconi, C. W. Kim, W. Kim, W. Gohn, F. X. Girod, N. Tyler, C. Djalali, J. A. Tan, P. Chatagnon, G. V. Fedotov, H. Voskanyan, A. D'Angelo, T. Chetry, I. Bedlinskiy, L. Elouadrhiri, M. Holtrop, F. Hauenstein, W. J. Briscoe, E. Pasyuk, S. Strauch, K. Joo, H. Atac, D. P. Watts, H. Egiyan, G. Angelini, L. El Fassi, I. I. Strakovsky, R. Dupre, M. Battaglieri, F. Sabatié, Luciano Pappalardo, D. Heddle, A. Deur, M. Ripani, G. Gavalian, V. Mokeev, D. Marchand, V. Lucherini, V. P. Kubarovsky, Michael Dugger, Fatiha Benmokhtar, Krishna Neupane, R. G. Fersch, O. Pogorelko, O. Soto, S. Niccolai, Vincent Mathieu, P. L. Cole, Z. W. Zhao, Alessandro Rizzo, E. Golovatch, P. Lenisa, K. Hicks, M. Ehrhart, S. Adhikari, T. B. Hayward, J. Zhang, M. Hattawy, J. W. Price, N. Dashyan, Yordanka Ilieva, L. Barion, G. Rosner, William Brooks, G. Ciullo, Y. Prok, L. Venturelli, D. S. Carman, R. A. Schumacher, A. El Alaoui, X. Wei, Nicholas Zachariou, J. C. Carvajal, S. Stepanyan, E. Voutier, A. Movsisyan, Adam P. Szczepaniak, D. Sokan, Z. E. Meziani, K. Livingston, K. P. Adhikari, H. Hakobyan, H. S. Jo, A. Kim, J. Ritman, S. Diehl, D. G. Ireland, V. Crede, O. Cortes, E. L. Isupov, R. Paremuzyan, S. Boiarinov, R. Cruz-Torres, Nicholas M. Harrison, U. Shrestha, M. Contalbrigo, C. Munoz Camacho, M. H. Wood, B. McKinnon, A. Celentano, R. W. Gothe, M. Mirazita, and N. Gevorgyan

Subjects
Physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Sigma, Photon energy, 01 natural sciences, Nuclear physics, Amplitude, 0103 physical sciences, Invariant mass, Nuclear Experiment, 010306 general physics, Phenomenology (particle physics)
Abstract

We present the first measurement of the exclusive reaction $\gamma p \rightarrow a_2(1320)^0 \, p$ in the photon energy range $3.5$-$5.5$ GeV and four-momentum transfer squared $0.2

Published
2020

12. Beam–target helicity asymmetry $E$ in $K^+$ $\Sigma^-$ photoproduction on the neutron

Author

R. De Vita, D. Marchand, H. Atac, H. S. Jo, A. Filippi, L. Marsicano, N. K. Walford, O. Soto, M. Khandaker, I. J. D. MacGregor, K. Hicks, W. Phelps, R. A. Schumacher, Michael Paolone, H. Hakobyan, W. Kim, G. Charles, F. Bossu, H. Lu, S. Joosten, J. W. Price, S. Diehl, C. Salgado, William Brooks, L. Venturelli, D. Heddle, V. P. Kubarovsky, I. Bedlinskiy, Z. E. Meziani, V. Mascagna, A. Celentano, R. W. Gothe, N. Markov, Alessandro Rizzo, W. Gohn, G. Asryan, Axel Schmidt, Dustin Keller, M. Ungaro, M. Guidal, M. Contalbrigo, M. Osipenko, Z. W. Zhao, Fatiha Benmokhtar, E. L. Isupov, Y. Prok, J. Poudel, O. Pogorelko, A. I. Ostrovidov, K. Park, M. J. Amaryan, Michael Wood, K. Hafidi, M. Holtrop, M. Ehrhart, C.D. Bass, V. A. Nikonov, A. D'Angelo, D. G. Jenkins, D. G. Ireland, G. Rosner, S. Boiarinov, E. Golovatch, P. Eugenio, K. Livingston, Luciano Pappalardo, K. Joo, M. Leali, Jie Zhang, T. Kageya, Volker D. Burkert, Y. Ghandilyan, A. S. Biselli, C. W. Kim, G. Gavalian, U. Shrestha, F.-X. Girod, Gerard Gilfoyle, M. Ripani, R. G. Fersch, H. Voskanyan, A. El Alaoui, G. Angelini, Nicholas Zachariou, J. C. Carvajal, W. J. Briscoe, P. L. Cole, T. Chetry, N. Gevorgyan, D. Ho, I. I. Strakovsky, A. M. Sandorfi, A. Deur, Victor Mokeev, D. Sokhan, T. R. O'Connell, Chaden Djalali, P. Nadel Turonski, T. Mineeva, M. Bashkanov, S. Adhikari, D. Bulumulla, E. Munevar, B. McKinnon, B. S. Ishkhanov, Aditya R. Khanal, Andrea Bianconi, I. Zonta, X. Wei, P. Peng, Hovanes Egiyan, C. Munoz Camacho, P. Lenisa, M. Hattawy, J. A. Fleming, Friedrich Klein, Brian Raue, Andrew Puckett, E. Voutier, Martin K. Mayer, M. Khachatryan, K. A. Griffioen, Nikolaos Sparveris, K. P. Adhikari, C. S. Whisnant, C. Hanretty, L. Lanza, R. Dupre, M. Battaglieri, M. Lowry, S. Strauch, Eugene Pasyuk, N. Dashyan, Yordanka Ilieva, L. Barion, G. Ciullo, D. S. Carman, S. Fegan, D. P. Watts, A. V. Sarantsev, N. Tyler, J. A. Tan, P. Chatagnon, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS

Subjects
Nuclear and High Energy Physics, Socio-culturale, nucleon resonance, Nucleons, Photoproduction, Mesons, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, K+: photoproduction, Particle identification, Nuclear physics, chemistry.chemical_compound, PE2_2, PE2_1, CLAS, 0103 physical sciences, Neutron, Hydrogen deuteride, n: target, 010306 general physics, Nuclear Experiment, PE2_3, photon: beam, Physics, 010308 nuclear & particles physics, nucleus: target, Settore FIS/04, Resonance, helicity: asymmetry, Observable, Sigma-: photoproduction, Helicity, lcsh:QC1-999, chemistry, Excited state, spectrometer, Nucleon, lcsh:Physics, Jefferson Lab, experimental results
Abstract

We report a measurement of a beam–target double-polarisation observable (E) for the γ→n→(p)→K+Σ−(p) reaction. The data were obtained impinging the circularly-polarised energy-tagged photon beam of Hall B at Jefferson Lab on a longitudinally-polarised frozen-spin hydrogen deuteride (HD) nuclear target. The E observable for an effective neutron target was determined for centre-of-mass energies 1.70≤W≤2.30 GeV, with reaction products detected over a wide angular acceptance by the CLAS spectrometer. These new double-polarisation data give unique constraints on the strange decays of excited neutron states. Inclusion of the new data within the Bonn-Gatchina theoretical model results in significant changes for the extracted photocouplings of a number of established nucleon resonances. Possible improvements in the PWA description of the experimental data with additional “missing” resonance states, including the N(2120)3/2− resonance, are also quantified.

Published
2020

13. The CLAS12 Spectrometer at Jefferson Laboratory

Author

C. W. Kim, H. Avakian, D. Protopopescu, D. Heddle, M. Contalbrigo, M. L. Kabir, H. Voskanyan, E. Voutier, T. Chetry, M. Zarecky, J. Poudel, I. Illari, B. A. Clary, M. Osipenko, D. Insley, D. P. Watts, I. Bedlinskiy, Michael Paolone, V. Sergeyeva, D. Kashy, M. Khachatryan, F. Hauenstein, V. Mascagna, Nikolaos Sparveris, F. Bossu, D. Marchand, W. Kim, G. Niculescu, P. Bonneau, G. Charles, P. Hemler, Ruben J. Fair, P. Moran, Dustin Keller, C. Ayerbe Gayoso, Nicholas Zachariou, M. Ungaro, C. Munoz Camacho, M. J. Amaryan, G. Rosner, I. J. D. MacGregor, T. A. Forest, V. Lucherini, S. E. Kuhn, Y. Prok, M. Hattawy, S. Stepanyan, Michael Wood, K. Hafidi, M. D. Mestayer, S. Lee, M. Wiseman, F. Sabatié, R. Paremuzyan, N. Dashyan, A. Deur, K. Hicks, K. Joo, E. L. Isupov, N. A. Baltzell, R. W. Gothe, S. Christo, L. C. Smith, B. S. Ishkhanov, Latifa Elouadrhiri, V. Baturin, Nicholas M. Harrison, Gerard Gilfoyle, M. McMullen, G. E. Dodge, H. S. Jo, R. Johnston, A. Yegneswaran, K. Livingston, A. Lung, P. Stoler, M. Guidal, D. Sokhan, K. Price, Aditya R. Khanal, K. P. Adhikari, Jie Zhang, K. Bruhwel, S. Adhikari, S. Boyarinov, B. McKinnon, M. Ehrhart, M. Leali, Z. W. Zhao, S. Joosten, B. J. Roy, V. P. Kubarovsky, J. Newton, P. Chatagnon, G. V. Fedotov, D. Tilles, M.A. Antonioli, Renuka Rajput-Ghoshal, G. D. Smith, M. Holtrop, C. Cuevas, V. Gyurjyan, Probir K. Ghoshal, Yordanka Ilieva, H. Hakobyan, Alexander Schmidt, Luciano Pappalardo, Andrea Bianconi, W. J. Briscoe, M. Turisini, M. Mirazita, D. I. Glazier, M. Garçon, M. Ripani, F. X. Girod, A. Filippi, K. L. Giovanetti, R. Miller, J. Ritman, S. Diehl, R. De Vita, C. D. Keith, Y. G. Sharabian, M. Lowry, M. Defurne, E. Pasyuk, P. Naidoo, J. Hogan, N. Markov, Or Hen, C. Salgado, M. Taylor, G. Young, S. Strauch, Larry Weinstein, H. Atac, Chaden Djalali, A. Hobart, A. Kim, Z. E. Meziani, S. Schadmand, U. Shrestha, T. Ewing, T. Mineeva, O. Pogorelko, S. Nanda, L. Barion, G. Angelini, J. Rowley, P. Rossi, M. Leffel, William Brooks, I. Mandjavidze, L. Venturelli, Iu. Skorodumina, Y. Gotra, C. Mealer, J. W. Price, S. Aune, C. Wiggins, D. G. Ireland, G. Gavalian, G. Jacobs, V. Crede, Volker D. Burkert, A. S. Biselli, O. Pastor, Victor Mokeev, E.P. Segarra, Ross Milner, N. Tyler, J. A. Tan, E. Golovatch, R. Dupre, W. Phelps, Andrea Celentano, S. Procureur, M. Cook, G. Ciullo, M. Battaglieri, D. S. Carman, B. Raydo, A. Rizzo, X. Wei, R. Cruz-Torres, S. Niccolai, K. A. Griffioen, B. Eng, A. Movsisyan, P. L. Cole, L. Lanza, G. Christiaens, A. D'Angelo, T. Kageya, L. El Fassi, P. Lenisa, V. Ziegler, C. Hanretty, D. Anderson, T. B. Hayward, Brian Raue, Fatiha Benmokhtar, O. Soto, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics::Instrumentation and Detectors, data acquisition, magnet: solenoid, superconductivity: torus, Solenoid, 01 natural sciences, Particle identification, Luminosity, momentum resolution, electron: beam, Nuclear Experiment, Instrumentation, QC, Physics, Luminosity (scattering theory), Settore FIS/04, Detector, Magnetic spectrometer, magnet: torus, performance, Nuclear and High Energy Physics, Meson, vertex detector, nucleon: interaction, CLAS12, Electromagnetic physics, Large acceptance, Socio-culturale, fabrication, beam: energy, Nuclear physics, PE2_1, CLAS, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, PE2_3, scintillation counter, Cherenkov radiation, detector: design, activity report, Spectrometer, 010308 nuclear & particles physics, nucleus, CLAS12, Electromagnetic physics, Large acceptance, Luminosity, Magnetic spectrometer, magnet: superconductivity, magnetic spectrometer, electromagnetic physics, large acceptance, luminosity, neutral particle, Automatic Keywords, calorimeter: electromagnetic, Cherenkov counter, spectrometer, particle identification, Beam (structure)
Abstract

International audience; The CEBAF Large Acceptance Spectrometer for operation at 12 GeV beam energy (CLAS12) in Hall B at Jefferson Laboratory is used to study electro-induced nuclear and hadronic reactions. This spectrometer provides efficient detection of charged and neutral particles over a large fraction of the full solid angle. CLAS12 has been part of the energy-doubling project of Jefferson Lab’s Continuous Electron Beam Accelerator Facility, funded by the United States Department of Energy. An international collaboration of 48 institutions contributed to the design and construction of detector hardware, developed the software packages for the simulation of complex event patterns, and commissioned the detector systems. CLAS12 is based on a dual-magnet system with a superconducting torus magnet that provides a largely azimuthal field distribution that covers the forward polar angle range up to 35 ∘ , and a solenoid magnet and detector covering the polar angles from 35° to 125° with full azimuthal coverage. Trajectory reconstruction in the forward direction using drift chambers and in the central direction using a vertex tracker results in momentum resolutions of < 1% and < 3%, respectively. Cherenkov counters, time-of-flight scintillators, and electromagnetic calorimeters provide good particle identification. Fast triggering and high data-acquisition rates allow operation at a luminosity of 1035 cm −2 s −1 . These capabilities are being used in a broad program to study the structure and interactions of nucleons, nuclei, and mesons, using polarized and unpolarized electron beams and targets for beam energies up to 11 GeV. This paper gives a general description of the design, construction, and performance of CLAS12.

Published
2020

14. 12C(e,e'pN) measurements of short range correlations in the tensor-to-scalar interaction transition region

Author

M. J. Amaryan, P. Lenisa, Jie Zhang, A. Beck, L. Marsicano, T. B. Hayward, U. Shrestha, Larry Weinstein, S. Strauch, Maxime Defurne, K. A. Griffioen, D. P. Watts, Friedrich Klein, R. Paremuzyan, Brian Raue, O. Pogorelko, J. Rowley, A. I. Ostrovidov, R. A. Schumacher, F. X. Girod, M. Duer, A. Denniston, E. Golovatch, R. Dupre, Nicholas M. Harrison, R. De Vita, I. I. Strakovsky, P. Eugenio, A. Deur, W. K. Brooks, A. Filippi, D. Sokhan, B. A. Clary, D. Protopopescu, Volker D. Burkert, A. S. Biselli, L. Lanza, M. Khandaker, N. Tyler, C. Djalali, E. Voutier, Michael Paolone, Y. G. Sharabian, X. Zheng, H. Atac, J. A. Tan, Y. Prok, D. S. Carman, I. Bedlinskiy, W. Phelps, V. Lucherini, M. Battaglieri, A. El Alaoui, Y. Ilieva, E. L. Isupov, Nicholas Zachariou, X. Wei, S. Mey-Tal Beck, S. Boiarinov, Hovanes Egiyan, F. Hauenstein, C. Munoz Camacho, J. W. Price, Taofeng Wang, Fatiha Benmokhtar, M. Khachatryan, Nikolaos Sparveris, N. Markov, A. Movsisyan, R. Cruz-Torres, T. A. Forest, O. Soto, D. Heddle, M. Ungaro, K. P. Adhikari, Douglas Higinbotham, Latifa Elouadrhiri, D. Marchand, P. Nadel-Turonski, S. Adhikari, B. McKinnon, M. Ripani, A. Kim, S. Stepanyan, I. Korover, M. Hattawy, M. Guidal, B. Mustapha, Z. W. Zhao, T. Mineeva, Or Hen, H. Hakobyan, M. Mirazita, J. Ritman, L. Barion, J.R. Pybus, M. Holtrop, S. Diehl, R. G. Fersch, C. Salgado, K. Joo, Luciano Pappalardo, T. Chetry, E.P. Segarra, H. S. Jo, D. G. Jenkins, M. Leali, Eugene Pasyuk, P. L. Cole, M. Ehrhart, G. Rosner, P. Chatagnon, A. D'Angelo, L. El Fassi, V. P. Kubarovsky, L. Venturelli, Krishna Neupane, C. W. Kim, H. Voskanyan, W. J. Briscoe, Dustin Keller, E. Piasetzky, D. Bulumulla, Michael Wood, K. Hafidi, Aditya R. Khanal, Andrea Bianconi, G. Niculescu, Alexander Schmidt, G. Gavalian, M. Osipenko, I. J. D. MacGregor, F. Sabatié, D. G. Ireland, V. Crede, M. Contalbrigo, Laura Clark, G. Angelini, K. Hicks, A. Celentano, R. W. Gothe, Alessandro Rizzo, V. Mascagna, S. Joosten, K. Livingston, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and The Clas Collaboration

Subjects
Nuclear and High Energy Physics, Nuclear Theory, dependence, CLAS, dynamics, isospin, energy, system, Astronomy & Astrophysics, Physics, QC1-999, Scalar (mathematics), FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Astrophysics, 01 natural sciences, Nuclear Theory (nucl-th), Momentum, High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, ddc:530, Tensor, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Nuclear theory, [PHYS]Physics [physics], Range (particle radiation), 010308 nuclear & particles physics, Settore FIS/04, Nuclear interaction, High Energy Physics - Phenomenology, Astronomy &amp, Atomic physics, Nucleon
Abstract

High-momentum configurations of nucleon pairs at short-distance are probed using measurements of the $^{12}$C$(e,e'p)$ and $^{12}$C$(e,e'pN)$ reactions (where $N$ is either $n$ or $p$), at high-$Q^2$ and $x_B>1.1$. The data span a missing-momentum range of 300--1000 MeV/c and are predominantly sensitive to the transition region of the strong nuclear interaction from a Tensor to Scalar interaction. The data are well reproduced by theoretical calculations using the Generalized Contact Formalism with both chiral and phenomenological nucleon-nucleon ($NN$) interaction models. This agreement suggests that the measured high missing-momentum protons up to $1000$ MeV/c predominantly belong to short-ranged correlated (SRC) pairs. The measured $^{12}$C$(e,e'pN)$ / $^{12}$C$(e,e'p)$ and $^{12}$C$(e,e'pp)$ / $^{12}$C$(e,e'pn)$ cross-section ratios are consistent with a decrease in the fraction of proton-neutron SRC pairs and increase in the fraction of proton-proton SRC pairs with increasing missing momentum. This confirms the transition from an isospin-dependent tensor $NN$ interaction at $\sim 400$ MeV/c to an isospin-independent scalar interaction at high-momentum around $\sim 800$ MeV/c as predicted by theoretical calculation., Accepted for publication in Physics Letters B. 7 pages, 3 figures, and online supplementary materials

Published
2021

15. Measurement of the antiproton–nucleus annihilation cross-section at low energy

Author

L. Venturelli, Y. Murakami, M. Prest, E. Lodi Rizzini, M. Corradini, Hiroyuki Yamada, Valerio Mascagna, M. Leali, Andrea Bianconi, Ryugo S. Hayano, Hossein Aghai-Khozani, Masaki Hori, and E. Vallazza

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Large Hadron Collider, Annihilation, 010308 nuclear & particles physics, Low energies, Antiproton annihilations, Nuclear reactions, Antineutron, 01 natural sciences, Nuclear physics, Cross section (physics), medicine.anatomical_structure, Low energy, Antiproton, 0103 physical sciences, medicine, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleus
Abstract

Systematic measurements of the annihilation cross sections of low energy antinucleons were performed at CERN in the 80's and 90's. However the antiproton data on medium-heavy and heavy nuclear targets are scarce. The ASACUSA Collaboration at CERN has measured the antiproton annihilation cross section on carbon at 5.3 MeV: the value is (1.73 ± 0.25) barn. The result is compared with the antineutron experimental data and with the theoretical previsions.

Published
2018

16. Antiproton-nucleus annihilation cross section at low energy

Author

Ryugo S. Hayano, M. Corradini, E. Lodi-Rizzini, Hossein Aghai-Khozani, E. Vallazza, Hiroyuki Yamada, M. Prest, M. Leali, Valerio Mascagna, L. Venturelli, Masaki Hori, Y. Murakami, and Andrea Bianconi

Subjects
Physics, Annihilation, 010308 nuclear & particles physics, QC1-999, Nuclear Theory, 01 natural sciences, Nuclear physics, Cross section (physics), Physics and Astronomy (all), Low energy, medicine.anatomical_structure, Antiproton, 0103 physical sciences, medicine, Physics::Accelerator Physics, Nuclear Experiment, 010306 general physics, Nucleus
Abstract

The antinucleon-nuclei annihilation cross sections at low energies were systematically measured at CERN in the 80’s and 90’s with the LEAR facility and later with the Antiproton Decelerator. Unfortunately only few data exist for very low energy antiprotons (p

Published
2018

17. Recent Developments from ASACUSA on Antihydrogen Detection

Author

Yasunori Yamazaki, B. Kolbinger, Hiroyuki Higaki, Johann Zmeskal, Yasuyuki Matsuda, Eberhard Widmann, M. Tajima, D. J. Murtagh, M. Leali, M. C. Simon, C. Sauerzopf, H. Breuker, Naofumi Kuroda, P. Dupre, M. Diermaier, Stefan Ulmer, Claude Amsler, Yasuyuki Kanai, Angela Gligorova, V. Mäckel, Y. Nagata, L. Venturelli, M. Fleck, Chloé Malbrunot, Takayoshi Kobayashi, O. Massiczek, and Valerio Mascagna

Subjects
Physics, Annihilation, 010308 nuclear & particles physics, QC1-999, Detector, Cosmic ray, Parity (physics), 01 natural sciences, Nuclear physics, Antiproton Decelerator, Physics and Astronomy (all), Hodoscope, Antiproton, 0103 physical sciences, Physics::Atomic and Molecular Clusters, High Energy Physics::Experiment, Physics::Atomic Physics, Detectors and Experimental Techniques, Nuclear Experiment, 010306 general physics, Antihydrogen
Abstract

The ASACUSA Collaboration at CERNs Antiproton Decelerator aims to measure the ground state hyperfine splitting of antihydrogen with high precision to test the fundamental symmetry of CPT (combination of charge conjugation, parity transformation, and time reversal). For this purpose an antihydrogen detector has been developed. Its task is to count the arriving antihydrogen atoms and therefore distinguish backgroundevents (mainly cosmics) from antiproton annihilations originating from antihydrogen atoms which are produced only in small amounts. A central BGO crystal disk with position sensitive read-out detects the annihilation and a surrounding two-layered hodoscope is used for tracking charged secondaries. The hodoscope has been recently upgraded to allow precise vertex reconstruction. A machine learning analysis based on measured antiproton annihilations and cosmic rays has been developed to identify antihydrogen events.

Published
2018

18. Monte-Carlo based performance assessment of ASACUSA's antihydrogen detector

Author

Eberhard Widmann, M. Tajima, M. C. Simon, Horst Breuker, Yugo Nagata, L. Venturelli, Yasuyuki Kanai, C. Sauerzopf, B. Kolbinger, Chloé Malbrunot, Stefan Ulmer, Naofumi Kuroda, Hiroyuki Higaki, Johann Zmeskal, V. Mäckel, M. Fleck, Yasuyuki Matsuda, and Yasunori Yamazaki

Subjects
Nuclear and High Energy Physics, Antimatter, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, Tracker, Monte Carlo method, FOS: Physical sciences, Cosmic ray, Scintillator, 01 natural sciences, Nuclear physics, Hodoscope, 0103 physical sciences, Detectors and Experimental Techniques, 010306 general physics, Antihydrogen, Nuclear Experiment, Instrumentation, physics.ins-det, Physics, Calorimeter, Detector, 010308 nuclear & particles physics, Instrumentation and Detectors (physics.ins-det), Antiproton
Abstract

An antihydrogen detector consisting of a thin BGO disk and a surrounding plastic scintillator hodoscope has been developed. We have characterized the two-dimensional positions sensitivity of the thin BGO disk and energy deposition into the BGO was calibrated using cosmic rays by comparing experimental data with Monte-Carlo simulations. The particle tracks were defined by connecting BGO hit positions and hits on the surrounding hodoscope scintillator bars. The event rate was investigated as a function of the angles between the tracks and the energy deposition in the BGO for simulated antiproton events, and for measured and simulated cosmic ray events. Identification of the antihydrogen Monte Carlo events was performed using the energy deposited in the BGO and the particle tracks. The cosmic ray background was limited to 12 mHz with a detection efficiency of 81%. The signal-to-noise ratio was improved from 0.22 s−1∕2 obtained with the detector in 2012 to 0.26 s−1∕2 in this work. An antihydrogen detector consisting of a thin BGO disk and a surrounding plastic scintillator hodoscope has been developed. We have characterized the two-dimensional positions sensitivity of the thin BGO disk and energy deposition into the BGO was calibrated using cosmic rays by comparing experimental data with Monte-Carlo simulations. The particle tracks were defined by connecting BGO hit positions and hits on the surrounding hodoscope scintillator bars. The event rate was investigated as a function of the angles between the tracks and the energy deposition in the BGO for simulated antiproton events, and for measured and simulated cosmic ray events. Identification of the antihydrogen Monte Carlo events was performed using the energy deposited in the BGO and the particle tracks. The cosmic ray background was limited to 12 mHz with a detection efficiency of 81 %. The signal-to-noise ratio was improved from 0.22 s^{-1/2} obtained with the detector in 2012 to 0.26 s^{-1/2} in this work.

Published
2018

19. Experimental technique for antiproton-nucleus annihilation cross section measurements at low energy

Author

Hossein Aghai-Khozani, M. Leali, Hiroyuki Yamada, Ryugo S. Hayano, M. Corradini, L. Venturelli, E. Lodi-Rizzini, Luigi Solazzi, Y. Murakami, Masaki Hori, Valerio Mascagna, E. Vallazza, and M. Prest

Subjects
Physics, Annihilation, 010308 nuclear & particles physics, QC1-999, 01 natural sciences, Nuclear physics, Cross section (physics), Physics and Astronomy (all), Low energy, medicine.anatomical_structure, Antiproton, 0103 physical sciences, medicine, Physics::Accelerator Physics, High Energy Physics::Experiment, 010306 general physics, Nuclear Experiment, Nucleus
Abstract

The interaction of very low energy antiprotons (ps) and antineutrons (ns) with nuclei is interesting for its influence on both fundamental cosmology and nuclear physics. Measuring the annihilation cross section of antimatter on matter can help in solving the universe matter-antimatter puzzle and could give relevant hints in the definition of strong interaction model parameters as well. The ASACUSA collaboration recently measured the antiproton-carbon annihilation cross section at 5.3 MeV of kinetic energy of the incoming antiproton. The experimental apparatus consisted in a vacuum chamber containing thin foils (~0.7-1 μm) of carbon crossed by a bunched beam of antiprotons from the CERN Antiproton Decelerator (AD). The fraction of antiprotons annihilating on the target nucleons gives origin to charged pions which can be detected and counted by segmented scintillators placed outside the chamber. This work describes the experimental details of the apparatus and the technique to perform the cross section measurements.

Published
2018

20. The ASACUSA CUSP: an antihydrogen experiment

Author

Eberhard Widmann, Johann Zmeskal, Yasunori Yamazaki, Nicola Zurlo, Kunio Suzuki, Yasuyuki Matsuda, Hiroyuki A. Torii, Naofumi Kuroda, S. Sakurai, O. Massiczek, E. Lodi Rizzini, K. Michishio, M. Leali, H. Nagahama, Yasuyuki Nagashima, Yugo Nagata, B. Wünschek, C. Sauerzopf, B. Radics, S. Van Gorp, M. Ohtsuka, Chloé Malbrunot, Stefan Ulmer, Yasuyuki Kanai, A. Mohri, M. Tajima, M. Diermaier, L. Venturelli, Valerio Mascagna, S. Federmann, Hiroyuki Higaki, D. J. Murtagh, and T. Mizutani

Subjects
Rydberg atom, Nuclear and High Energy Physics, Antiparticle, Physics::Instrumentation and Detectors, Scintillator, Particle detector, Nuclear physics, Atomic beam, Atomic and Molecular Physics, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, Physical and Theoretical Chemistry, Nuclear Experiment, Antihydrogen, Physics, CPT invariance, Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Beamline, Antiproton, Antimatter, Scintillation counter, and Optics, Atomic physics
Abstract

In order to test CPT symmetry between antihydrogen and its counterpart hydrogen, the ASACUSA collaboration plans to perform high precision microwave spectroscopy of ground-state hyperfine splitting of antihydrogen atom in-flight. We have developed an apparatus (“cusp trap”) which consists of a superconducting anti-Helmholtz coil and multiple ring electrodes. For the preparation of slow antiprotons and positrons, Penning- Malmberg type traps were utilized. The spectrometer line was positioned downstream of the cusp trap. At the end of the beamline, an antihydrogen beam detector was located, which comprises an inorganic Bismuth Germanium Oxide (BGO) single-crystal scintillator housed in a vacuum duct and surrounding plastic scintillators. A significant fraction of antihydrogen atoms flowing out the cusp trap were detected.

Published
2015

21. The Development of the Antihydrogen Beam Detector: Toward the Three Dimensional Tracking with a BGO Crystal and a Hodoscope

Author

M. Tajima, Yasuyuki Matsuda, Naofumi Kuroda, Yasunori Yamazaki, Chloé Malbrunot, P. Dupre, Eberhard Widmann, Horst Breuker, C. Kaga, Yasuyuki Kanai, Valerio Mascagna, M. Leali, Yugo Nagata, C. Sauerzopf, O. Massiczek, B. Radics, E. Lodi Rizzini, M. C. Simon, A. A. Capon, L. Venturelli, B. Kolbinger, Hiroyuki Higaki, and T. Matsudate

Subjects
Physics, Physics::General Physics, Physics::Instrumentation and Detectors, Detector, Scintillator, Tracking (particle physics), Crystal, Nuclear physics, Hodoscope, High Energy Physics::Experiment, Development (differential geometry), Physics::Atomic Physics, Detectors and Experimental Techniques, Nuclear Experiment, Antihydrogen, Beam (structure)
Abstract

We developed an antihydrogen beam detector for the microwave spectroscopy of the antihydrogen hyperfine splitting. The detector consists of a position sensitive BGO calorimeter and a hodoscope. We report test experiments for the position sensitive readout from a non-segmented BGO crystal., Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016), ISBN:978-4-89027-125-2

Published
2017

22. Experimental investigation of ≈130 keV kinetic energy antiprotons annihilation on nuclei

Author

Hossein Aghai-Khozani, D. Barna, N. Zurlo, M. Leali, Ryugo S. Hayano, M. Corradini, M. Prest, E. Lodi-Rizzini, Takayoshi Kobayashi, L. Venturelli, K. Todoroki, E. Vallazza, Valerio Mascagna, Anna Sótér, and Masaki Hori

Subjects
Nuclear and High Energy Physics, antiprotons, annihilation cross section, nuclear physics, CERN AD, media_common.quotation_subject, Nuclear Theory, Antiproton, Kinetic energy, Asymmetry, Nuclear physics, nuclear physics, Atomic and Molecular Physics, Coulomb, Neutron, Physical and Theoretical Chemistry, Nuclear Experiment, media_common, Mass number, Physics, Annihilation cross section, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Annihilation, Antimatter, and Optics, Atomic physics, antiprotons
Abstract

The study of the antiproton ( $\bar {p}$ ) annihilation cross section on nuclei at low energies (eV-MeV region) has implications for fundamental cosmology as well as for nuclear physics. Concerning the former, different models try to explain the matter/antimatter asymmetry in the universe assuming the existence of the so-called “islands” where antinucleon-nucleon annihilations occur in the border region (Cohen et al. Astrophys. J. 495, 539–549, 1998), while, from the nuclear physics point of view, the annihilation process is a valuable tool to evaluate the neutron/proton ratio in order to probe the external region of the nucleus (Gupta et al. Nucl. Phys. B 70(3), 414–424, 1974). The existing data of antinucleon-nucleon (or -nucleus) annihilation cross-sections are mainly confined to energies above ≈1 MeV, while the cross section measured at LEAR in the 80’s-90’s (mostly with light targets Agnello et al. Phys. Lett. B 256, 349–353, 1991; Bertin et al. Phys. Lett. B 369, 77–85, 1996; Bertin et al. Phys. Lett. B 414, 220–228, 1997; Zenoni et al. Phys. Lett. B 461, 405–412, 1999; Bianconi et al. Phys. Lett. B 481, 194–198, 2000; Bianconi et al. Phys. Lett. B 492, 254–258, 2000) showed an unexpected behaviour for energies below 1 MeV (Bianconi et al. Phys. Lett. B 483, 353–359, 2000; Bianconi et al. Phys. Rev. C 62, 014611-7, 2000; Batty et al. Nucl. Phys. A 689, 721–740, 2001). The results showed a saturation with the atomic mass number against the A 2/3 trend which is observed for higher energies (being A the target mass number). The ASACUSA collaboration at CERN recently measured antiproton annihilation cross section on different kinds of nuclei with a $\bar {p}$ kinetic energy of 5.3 MeV (Bianconi et al. Phys. Lett. B 704, 461–466, 2011; Corradini et al. Nucl. Instr. Methods A 711, 12–20, 2013). Such results proved compatibility with the black-disk model with the Coulomb correction. But till now experimental difficulties prevented the investigation at energies below ≈1 MeV. In 2012, the 100 keV region has been investigated for the first time (Aghai-Khozani et al. Eur. Phys. J. Plus 127, 125–128, 2012). We present here the first preliminary results of this experiment.

Published
2014

23. New results of the antiproton-carbon annihilation cross section measurement at low energies

Author

Masaki Hori, M. Prest, Hiroyuki Yamada, M. Corradini, E. Vallazza, E. Lodi Rizzini, L. Venturelli, Y. Murakami, H Aghai–Khozani, Ryugo S. Hayano, Mascagna, M. Leali, and Luigi Solazzi

Subjects
Physics, Large Hadron Collider, Annihilation, 010308 nuclear & particles physics, QC1-999, Nuclear Theory, chemistry.chemical_element, 01 natural sciences, Antiproton Decelerator, Nuclear physics, Cross section (physics), Physics and Astronomy (all), Low energy, chemistry, Antiproton, 0103 physical sciences, Physics::Accelerator Physics, Nuclear Physics - Experiment, Physics::Atomic Physics, 010306 general physics, Nuclear Experiment, Carbon
Abstract

The antinucleon-nuclei annihilation cross section at very low energy has been measured at the LEAR facility (CERN) during the 80's and 90's and recently at the Antiproton Decelerator. The results have raised some interesting questions that still need answers. The ASACUSA collaboration performed an experiment to measure the sigma_ann of 100 MeV/c antiprotons on carbon target and the preliminary results are presented here.

Published
2016

24. Direct detection of antihydrogen atoms using a BGO crystal

Author

L. Venturelli, Mascagna, H. A. Torii, M. Leali, Yasuyuki Matsuda, Yasunori Yamazaki, M. Tajima, Yugo Nagata, E. Lodi-Rizzini, Naofumi Kuroda, Miki Ohtsuka, and N. Zurlo

Subjects
Physics::General Physics, Antimatter, Nuclear and High Energy Physics, Cosmic ray, 01 natural sciences, Spectral line, Nuclear physics, Pion, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, Multiplicity (chemistry), Nuclear Experiment, 010306 general physics, Antihydrogen, Instrumentation, Physics, Cosmic ray background suppression, Detector, Inorganic scintillator, Annihilation, 010308 nuclear & particles physics, Atomic physics
Abstract

The ASACUSA collaboration has developed a detector consisting of a large size BGO crystal to detect an atomic antihydrogen beam, and performed the direct detection of antihydrogen atoms. Energy spectra from antihydrogen annihilation on the BGO crystal are discussed in comparison to simulation results from the GEANT4 toolkit. Background mainly originating from cosmic rays were strongly suppressed by analyzing the energy deposited in the BGO and requiring a multiplicity of charged pions. Thus antihydrogen events were identified.

Published
2016

25. Mass discrimination using double-sided silicon microstrip detectors for pions and protons at intermediate energies

Author

Paolo Camerini, Rinaldo Rui, L. Venturelli, L. Celano, Richard Wheadon, M. De Palma, N. Grion, P. Bottan, L. Fiore, V. Paticchio, F. De Mori, P., Bottan, Camerini, Paolo, L., Celano, F., DE MORI, M., DE PALMA, L., Fiore, N., Grion, V., Paticchio, Rui, Rinaldo, L., Venturelli, and R., Wheadon

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Silicon, Physics::Instrumentation and Detectors, Nuclear Theory, Detector, chemistry.chemical_element, Ranging, Integrated circuit, law.invention, Nuclear physics, Pion, chemistry, law, Silicon detector, Mass discrimination, High Energy Physics::Experiment, Nuclear Experiment, Instrumentation, Silicon microstrip detectors
Abstract

Prototype silicon detector modules for the vertex detector of the FINUDA experiment were tested at TRIUMF using pions and protons at 270 and 408 MeV/c in order to study their use for mass discrimination based on energy deposition. The detector modules were constructed using double-sided silicon detectors based on the ALEPH design, read out by VA1 integrated circuits. The test modules and apparatus are described, details of the data analysis are discussed, and the results are presented together with GEANT simulations. Particular attention is given to the detector response for the various particles, with signals ranging from the minimum-ionising pions at 408 MeV/c up to 20 times minimum-ionising for the protons at 270 MeV/c. ( 1999 Elsevier Science B.V. All rights reserved.

Published
1999

26. Scintillating bar detector for antiproton annihilations measurements

Author

M. Corradini, E. Lodi Rizzini, M. Prest, L. Venturelli, Valerio Mascagna, M. Leali, and E. Vallazza

Subjects
Physics, Nuclear and High Energy Physics, Large Hadron Collider, Scintillating bar detector, Annihilation cross section, Physics::Instrumentation and Detectors, Detector, Antiproton, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Particle detector, Antiproton Decelerator, Nuclear physics, Data acquisition, Antimatter, Atomic and Molecular Physics, Antihydrogen, Physical and Theoretical Chemistry, High Energy Physics::Experiment, and Optics, Nuclear Experiment
Abstract

A detector used in two different experiments of the ASACUSA Collaboration at the CERN Antiproton Decelerator is presented. It consists of several modules, each one made of ~1 m long scintillating bars, which allows the detection of the charged particles produced in the antiproton-nuclei annihilations. The modularity of the detector, its electronics readout and the data acquisition system have been designed to be adapted to different experimental conditions.

Published
2015

27. Search for the pentaquark in antiproton 4He annihilation at rest

Author

Piergiorgio Cerello, G. Puddu, M. Corradini, Felice Iazzi, C. Guaraldo, Corrado Cicalo, Adriano Fontana, A.M. Rozhdestvensky, L. Busso, L. Venturelli, A. Feliciello, Alberto Masoni, D. Calvo, Aldo Zenoni, Paola Salvini, Bruno Minetti, Armando Lanaro, V.I. Tretyak, A. Maggiora, L. Ferrero, S.N. Prakhov, S. Costa, O.E. Gorchakov, R. Garfagnini, G. L. Usai, Alberto Rotondi, V. Lucherini, Antonietta Donzella, Michelangelo Agnello, O. Y. Denisov, Paolo Montagna, M.P. Bussa, L. Lavezzi, D. Panzieri, Tullio Bressani, Elena Botta, Catalina Curceanu, E. Lodi Rizzini, S. Serci, G. Bendiscioli, A. Filippi, A. Grasso, A. Panzarasa, F. Balestra, S. Marcello, G. M. Sapozhnikov, A. De Falco, P. Gianotti, and F. Tosello

Subjects
Baryon, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Antiproton, Invariant mass, Strangeness, Nuclear Experiment, Nucleon, Resonance (particle physics), Pentaquark
Abstract

A research has been made to look for a signature of the positive-strangeness baryon resonance Θ + ( 1530 ) , which is expected to decay into p K 0 . A peak is observed in the p π + π − invariant mass distribution in antiproton– 4 He annihilation reactions at rest with production of two π + π − pairs with invariant mass close to the K S 0 mass. The annihilation reactions on 4 He can involve two to four nucleons producing an energy blob characterized by high strangeness content. The peak is centred around 1560.0 ± 3.7 MeV and its width is very narrow. The statistical significance is 2.7; this value is considered of not sufficient significance to claim support of the Θ + . The data were collected with the Obelix spectrometer at the LEAR machine of CERN.

Published
2006

28. First results on nuclear physics with antineutrons by the OBELIX spectrometer

Author

M. Morando, Paolo Montagna, A. Grasso, S. De Castro, Felice Iazzi, L. Ferrero, A. Bertin, I. Massa, S. Marcello, Corrado Cicalo, S. Serci, U. Marconi, L. Vannucci, M. Lombardi, F. D'Isep, G. Maron, L. Busso, M. Corradini, G. Bendiscioli, N. Semprini Cesari, D. Galli, M.G. Sapozhnikov, L. Santi, Alberto Rotondi, L. Fava, R. Garfagnini, F. Nichitiu, S. Costa, M. Capponi, C. Guaraldo, Tullio Bressani, U. Gastaldi, G. L. Usai, V. Lucherini, A. Vitale, G. V. Margagliotti, V. Filippini, G. Pauli, R. A. Ricci, A. Maggiora, D. Panzieri, S. Tessaro, V.I. Tretyak, Aldo Zenoni, Mauro Villa, I. D'Antone, D. Calvo, Michelangelo Agnello, Guido Zavattini, Bruno Minetti, Antonio Zoccoli, P. Boccaccio, P. Gianotti, E. Lodi Rizzini, G. Piragino, A. Adamo, F. Balestra, G. Puddu, P.P. Temnikov, Gianfranco Zosi, Marco Bruschi, Alberto Masoni, E. Rossetto, L. Venturelli, F. Tosello, G. Bonazzola, A.M. Rozhdestvensky, Massimo Piccinini, Armando Lanaro, M. Poli, G. Vedovato, A. Feliciello, G. Belli, M.P. Bussa, Paola Salvini, A., Adamo, M., Agnello, F., Balestra, G., Belli, G., Bendiscioli, A., Bertin, P., Boccaccio, G. C., Bonazzola, T., Bressani, M., Bruschi, M. P., Bussa, L., Busso, D., Calvo, M., Capponi, C., Cicalò, M., Corradini, S., Costa, I., D'Antone, S., De Castro, F., D'Isep, L., Fava, A., Feliciello, L., Ferrero, V., Filippini, D., Galli, R., Garfagnini, U., Gastaldi, P., Gianotti, A., Grasso, C., Guaraldo, F., Iazzi, A., Lanaro, E., Lodi Rizzini, M., Lombardi, V., Lucherini, A., Maggiora, S., Marcello, U., Marconi, Margagliotti, Giacomo, G., Maron, A., Masoni, I., Massa, B., Minetti, M., Morando, P., Montagna, F., Nichitiu, D., Panzieri, G., Pauli, M., Piccinini, G., Piragino, M., Poli, G., Puddu, R. A., Ricci, E., Rossetto, A., Rotondi, A. M., Rozhdestvensky, P., Salvini, L., Santi, M. G., Sapozhnikov, N., Semprini Cesari, S., Serci, P., Temnikov, Tessaro, Susanna, F., Tosello, V. I., Tretyak, G. L., Usai, L., Vannucci, G., Vedovato, L., Venturelli, M., Villa, A., Vitale, G., Zavattini, A., Zenoni, A., Zoccoli, and G., Zosi

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Spectrometer, nbar-nucleus, Nuclear Theory, nbar-p, Antineutron, Nuclear physics, medicine.anatomical_structure, medicine, Nuclear Experiment, Spectroscopy, Nucleon, Nucleus
Abstract

First results on n annihilations on nucleons and nuclei measured by the OBELIX spectrometer are reported. Interesting new results on meson spectroscopy were obtained. Furthermore n-p and n - Nucleus (C, Al, Cu, Sn, Pb) annihilation cross sections between 100 and 300 MeV/c were measured.

Published
1993

29. Single and multinucleon antiproton–4He annihilation at rest

Author

Paola Salvini, V.G. Ableev, V.I. Tretyak, A. Maggiora, V. Lucherini, M. Bargiotti, Antonietta Donzella, D. Panzieri, Felice Iazzi, S. De Castro, Corrado Cicalo, G. Bendiscioli, Tullio Bressani, Umberto Marini Bettolo Marconi, M.P. Bussa, Germano Bonomi, L. Venturelli, A. Bertin, L. Ferrero, A. Feliciello, V. Filippini, R. Garfagnini, N. Mirfakhrai, Alberto Masoni, D. Galli, Marco Bruschi, Alberto Rotondi, C. Cavion, A.M. Rozhdestvensky, Aldo Zenoni, C. Petrascu, D. Calvo, G. Puddu, A. Panzarasa, M. Astrua, A. Grasso, S. Marcello, Mauro Villa, O.E. Gorchakov, F. Balestra, C. Guaraldo, Piergiorgio Cerello, A. Filippi, Massimo Piccinini, Roberto Spighi, Adriano Fontana, Antonio Zoccoli, Andrea Bianconi, G. L. Usai, A. Vitale, N. Semprini Cesari, Stefania Vecchi, Pietro Faccioli, Armando Lanaro, M. Capponi, V. Vagnoni, Elena Botta, Michelangelo Agnello, G. Vedovato, Paola Gianotti, A. De Falco, S. Serci, Benedetto Giacobbe, Paolo Montagna, L. Busso, Laura Fabbri, and O. Y. Denisov

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Branching fraction, Hadron, Nuclear physics, Pion, Antiproton, Physics::Accelerator Physics, Nuclear Experiment, Nucleon
Abstract

The p annihilation at rest in a NTP 4He-gas target has been studied by means of the Obelix spectrometer installed at the LEAR accelerator of CERN. Reactions with production of 2π−2π+, 2π−3π+, 2π−2π+p, 2π−π+2p, 2π−3p (with pπ>80 MeV/c and pp>300 MeV/c) have been selected and single- and multinucleon annihilations identified. For the first time some known mesonic and baryonic resonances have been observed in p 4He annihilations and branching ratios are evaluated for a number of reaction channels.

Published
2002

30. Near-infrared laser spectroscopy of antiprotonic helium atoms

Author

Andreas Dax, H. Aghai-Khozani, Dezso Horvath, L. Venturelli, Y. Murakami, Ryugo S. Hayano, K. Todoroki, Masaki Hori, D. Barna, Hideaki Yamada, Nicola Zurlo, Takumi Kobayashi, and Anna Sótér

Subjects
Physics, QC1-999, chemistry.chemical_element, Atomic spectroscopy, Electron, Nanosecond, Laser, Charged particle, law.invention, Physics and Astronomy (all), chemistry, law, Physics in General, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, Atomic physics, Spectroscopy, Nuclear Experiment, Antiprotonic helium, Helium
Abstract

The ASACUSA (Atomic Spectroscopy and Collisions Using Slow Antipro- tons) collaboration is currently attempting to observe a laser-induced resonant transition of antiprotonic helium atoms at wavelength of 1154.9 nm. Motivations to observe this transition and a nanosecond near-infrared laser prepared for this work are presented.

Published
2014

31. and annihilation cross sections at very low energy

Author

N. Semprini Cesari, D. Galli, Andrea Bianconi, G. L. Usai, M.P. Bussa, Piergiorgio Cerello, S. Costa, G. Bendiscioli, Paola Salvini, Stefania Vecchi, R. A. Ricci, S.N. Prakhov, Adriano Fontana, I. Massa, N. Mirfakhrai, S. Marcello, L. Ferrero, L. Venturelli, C. Guaraldo, Maurizio Piccinini, R. Garfagnini, R. Spighi, F. D'Isep, Alberto Rotondi, Armando Lanaro, U. Marconi, M. Corradini, M. Capponi, A. Panzarasa, C. Petrascu, F. Tosello, S. Tessaro, G. Puddu, Tullio Bressani, A. Grasso, S. De Castro, A. Vitale, Elena Botta, U. Gastaldi, Antonio Zoccoli, S. Mauro, V.I. Tretyak, Alberto Masoni, S. Serci, M. Poli, Antonietta Donzella, A. Feliciello, V. Lucherini, D. Calvo, B. Giacobbe, Mauro Villa, V. Vagnoni, Paola Gianotti, Felice Iazzi, Corrado Cicalo, O.E. Gorchakov, Germano Bonomi, D. Panzieri, Michelangelo Agnello, A.M. Rozhdestvensky, A. Filippi, R. Donà, E. Lodi Rizzini, Aldo Zenoni, A. Bertin, Bruno Minetti, Marco Bruschi, F. Balestra, L. Vannucci, O. Y. Denisov, Paolo Montagna, and L. Busso

Subjects
Nuclear physics, Momentum, Physics, Nuclear and High Energy Physics, Cross section (physics), Low energy, Annihilation, Deuterium, Nuclear Experiment
Abstract

The p D and p 4 He total annihilation cross sections have been measured with the Obelix apparatus at LEAR at, respectively, three and two values of the p incident momentum between 70 MeV/c and 36 MeV/c. The values of the p D annihilation cross section, at such low energies, are in agreement with a surprising result obtained in a recent low statistics measurement of the antiprotonic deuterium K α X-rays [M. Augsburger et al., Phys. Lett. B 461 (1999) 417] (see following article), concerning the unexpected narrow width of the antiprotonic deuterium 1s level.

Published
1999

32. Study of and annihilation reactions in flight

Author

D. Panzieri, E. Lodi Rizzini, Alberto Masoni, G. Vedovato, D. Calvo, N. Semprini Cesari, Paolo Montagna, Paola Gianotti, V. Filippini, L. Santi, G. Bendiscioli, Antonietta Donzella, C. Cavion, Aldo Zenoni, A.M. Rozhdestvensky, Michelangelo Agnello, B. Giacobbe, C. Guaraldo, O. Y. Denisov, C. Fanara, S. Costa, S.N. Prakhov, R. Spighi, M. Lombardi, V. Vagnoni, A. Grasso, L. Valacca, O.E. Gorchakov, A. Raimondo, L. Venturelli, M.G. Sapozhnikov, M. Corradini, V. Alberico, F. Nichitiu, M. Capponi, L. Busso, G. Pauli, A. Panzarasa, Tullio Bressani, U. Gastaldi, V.G. Ableev, F. Balestra, S. De Castro, M.P. Bussa, Stefania Vecchi, Piergiorgio Cerello, M. Poli, Armando Lanaro, A. Feliciello, S. Serci, U. Marconi, V.I. Tretyak, G. Maron, A. Maggiora, Paola Salvini, A. Vitale, V. Lucherini, S. Mauro, D. Bergo, Bruno Minetti, F. Vigotti, L. Vannucci, Antonio Zoccoli, Mauro Villa, Elena Botta, S. Marcello, Marco Bruschi, R. Garfagnini, G. L. Usai, L. Ferrero, Alberto Rotondi, C. Petrascu, D. Galli, Maurizio Piccinini, Gianfranco Zosi, Adriano Fontana, A. Ferretti, N. Mirfakhraee, F. Tosello, S. Tessaro, C. Scoglio, Felice Iazzi, Corrado Cicalo, A. Filippi, R. Donà, Petar Temnikov, A. Bertin, and G. Puddu

Subjects
Physics, Nuclear physics, Nuclear reaction, Nuclear and High Energy Physics, Annihilation, Pion, Meson, OZI rule, Nuclear Theory, Nuclear Experiment, Nucleon, Antineutron, Quarkonium
Abstract

The results of a study of the annihilation reactions n p → θπ + and n p → ωπ + are reported; the data were collected by the OBELIX apparatus, with antineutrons annihilating in flight (momenta from ∼ 50 MeV/ c to 405 MeV/ c ). Annihilation frequencies and annihilation cross sections have been deduced, for both channels, as a function of antineutron momentum. From the cross section ratio, a substantial deviation from OZI rule expectations is observed. An s s quark content in the nucleon offers a fairly plausible explanation for such an effect.

Published
1999

33. pbar p annihilation into four charged pions at rest and in flight

Author

P. SALVINI, V. I. TRETYAK, V. FILIPPINI, A. FONTANA, P. MONTAGNA, A. PANZARASA, A. ROTONDI, M. BRUSCHI, B. GIACOBBE, U. MARCONI, R. SPIGHI, S. VECCHI, A. BIANCONI, M. CORRADINI, A. DONZELLA, E. LODI RIZZINI, L. VENTURELLI, A. ZENONI, C. CICALÒ, A. DE FALCO, A. MASONI, G. PUDDU, S. SERCI, G. USAI, O. E. GORCHAKOV, S. N. PRAKHOV, A. M. ROZHDESTVENSKY, M. G. SAPOZHNIKOV, M. POLI, P. GIANOTTI, C. GUARALDO, A. LANARO, V. LUCHERINI, C. PETRASCU, D. PANZIERI, F. BALESTRA, M. P. BUSSA, L. BUSSO, P. CERELLO, O. DENISOV, L. FERRERO, A. GRASSO, A. MAGGIORA, F. TOSELLO, E. BOTTA, T. BRESSANI, D. CALVO, F. DE MORI, A. FELICIELLO, A. FILIPPI, S. MARCELLO, M. AGNELLO, F. IAZZI, BARGIOTTI, MARIANNE, BERTIN, ANTONIO, CAPPONI, MARCO, CARBONE, ANGELO, DE CASTRO, STEFANO, FABBRI, LAURA, FACCIOLI, PIETRO, GALLI, DOMENICO, GRIMALDI, FILIPPO, MASSA, IGNAZIO GIACOMO, PICCININI, MAURIZIO, SEMPRINI CESARI, NICOLA, VILLA, MAURO, VITALE, ANTONIO, ZOCCOLI, ANTONIO, P. SALVINI, V.I. TRETYAK, V. FILIPPINI, A. FONTANA, P. MONTAGNA, A. PANZARASA, A. ROTONDI, M. BARGIOTTI, A. BERTIN, M. BRUSCHI, M. CAPPONI, A. CARBONE, S. DE CASTRO, L. FABBRI, P. FACCIOLI, D. GALLI, B. GIACOBBE, F. GRIMALDI, U. MARCONI, I. MASSA, M. PICCININI, N. SEMPRINI CESARI, R. SPIGHI, S. VECCHI, M. VILLA, A. VITALE, A. ZOCCOLI, A. BIANCONI, M. CORRADINI, A. DONZELLA, E. LODI RIZZINI, L. VENTURELLI, A. ZENONI, C. CICALÒ, A. DE FALCO, A. MASONI, G. PUDDU, S. SERCI, G. USAI, O.E. GORCHAKOV, S.N. PRAKHOV, A.M. ROZHDESTVENSKY, M.G. SAPOZHNIKOV, M. POLI, P. GIANOTTI, C. GUARALDO, A. LANARO, V. LUCHERINI, C. PETRASCU, D. PANZIERI, F. BALESTRA, M.P. BUSSA, L. BUSSO, P. CERELLO, O. DENISOV, L. FERRERO, A. GRASSO, A. MAGGIORA, F. TOSELLO, E. BOTTA, T. BRESSANI, D. CALVO, F. DE MORI, A. FELICIELLO, A. FILIPPI, S. MARCELLO, M. AGNELLO, and F. IAZZI

Subjects
High Energy Physics::Experiment, Nuclear Experiment
Abstract

The spin-parity analysis of the data on the pbar p → 2π+ 2π− annihilation reaction at rest in liquid and in gaseous hydrogen at 3 bar pressure and in flight at p momentum of ~ 50 MeV/c, collected by the Obelix spectrometer at the LEAR complex of CERN, is presented. The relative branching ratios (a1(1260) → σπ)/(a1(1260) → ρπ) = 0.06 ± 0.05 and (π(1300) → σπ)/(π(1300) → ρπ) = 2.2 ± 0.4 are obtained. It is also shown that the inclusion of the exotic meson π1(1400), JPC= 1−+, mass and width M = 1.384 ± 0.028, Γ = 0.378 ± 0.058 GeV/c2, in its decay to ρπ, improves the fit and some implications of these results are briefly discussed. The relative S and P-wave annihilation percentages in four charged pions at two target densities are obtained.

Published
2004

34. Experimental apparatus for annihilation cross-section measurements of low energy antiprotons

Author

Aldo Mozzanica, M. Leali, Masaki Hori, Matteo Ferroni, N. Zurlo, L. Venturelli, Ryugo S. Hayano, Camilla Baratto, E. Vallazza, M. Corradini, M. Prest, Alberto Vomiero, Valerio Mascagna, K. Todoroki, and E. Lodi Rizzini

Subjects
antinucleon-nucleon interaction, Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Annihilation, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, antiproton decelerator, Antiproton Decelerator, Experimental physics, Nuclear physics, Cross section (physics), Low energy, Antiproton, scintillating tracker, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, Instrumentation
Abstract

The nuclear physics program of the ASACUSA experiment at the Antiproton Decelerator (AD) at CERN is concerned with the measurements of antiproton-nuclei cross-sections at low energies (from 5.3 MeV down to the 100 keV region). These measurements are expected to contribute to understand the dynamics of the annihilation process. We give here a full description of the experimental apparatus used for the measurements at 5.3 MeV.

Published
2013

35. Two-photon laser spectroscopy of antiprotonic helium and the antiproton-electron mass ratio

Author

B. Juhász, S. Friedreich, Nicola Zurlo, L. Venturelli, Dezso Horvath, Andreas Dax, Eberhard Widmann, T. Pask, D. Barna, Anna Sótér, Masaki Hori, and Ryugo S. Hayano

Subjects
Nuclear physics, Physics, Proton, Antiproton, Electron rest mass, Physics::Atomic Physics, Electron, Mass ratio, Atomic physics, Nuclear Experiment, Spectroscopy, Antiprotonic helium, Atomic mass
Abstract

We report our latest results from our two-photon spectroscopy of antiprotonic helium (a bound state of a helium nucleus, an electron and an antiproton). By measuring three transition frequencies with a precision of 2.3−5×10−9 and comparing these to 3-body QED calculations, we derived the antiproton-electron mass ratio 1,836.1526736(23),which agrees with the proton-electron mass ratio (known to a three-times better precision) within the errors. Since the (anti)proton's atomic mass is known to a better precision than that of the electron, assuming mp = mp this result can be used to determine the electron's atomic mass as me=0.0005485799091(7) u.

Published
2013

36. Antiproton Slowing Down inH2and He and Evidence of Nuclear Stopping Power

Author

Tullio Bressani, M. Corradini, L. Ferrero, Alberto Rotondi, Bruno Minetti, F. Tosello, S. Tessaro, F. Nichitiu, E. Botta, E. Rossetto, M.P. Bussa, G. Pauli, G. Puddu, Stefania Vecchi, S. De Castro, B. Cereda, S. Serci, A. Grasso, D. Galli, C. Guaraldo, N. Semprini Cesari, M.G. Sapozhnikov, L. Santi, Roberto Spighi, D. Panzieri, L. Venturelli, A. Vitale, Alessandro Feliciello, U. Marconi, Paola Gianotti, V. Filippini, P. Cerello, Mauro Villa, S. Costa, Paola Salvini, L. Busso, Antonio Zoccoli, R. Garfagnini, A. Bertin, M. Morando, Aldo Zenoni, A. Filippi, A.M. Rozhdestvensky, G. Belli, Paolo Montagna, V.I. Tretyak, Benedetto Giacobbe, V. Lucherini, E. Lodi Rizzini, Armando Lanaro, Antonietta Donzella, M. Bruschi, M. Piccinini, S. Marcello, G. Bendiscioli, A. Saino, Felice Iazzi, Corrado Cicalo, G. L. Usai, Michelangelo Agnello, P.P. Temnikov, Adriano Fontana, Alberto Masoni, and D. Calvo

Subjects
Physics, Antiparticle, Annihilation, General Physics and Astronomy, Charged particle, Nuclear physics, Baryon, Antiproton, Antimatter, Physics::Accelerator Physics, Stopping power (particle radiation), Physics::Atomic Physics, Atomic physics, Nuclear Experiment, Nucleon
Abstract

We report stopping powers of hydrogen and helium for antiprotons of kinetic energies ranging from about 0.5 keV to 1.1 MeV. The Barkas effect, i.e., a difference in the stopping power for antiprotons and protons of the same energy in the same material, shows up clearly in either of the gases. Moreover, below [approx]0.5 keV there is indirect evidence for an increase of the antiproton stopping power. This nuclear'' effect, i.e., energy losses in quasimolecular interactions, shows up in fair agreement with theoretical predictions.

Published
1995

37. First experimental detection of antiproton in-flight annihilation on nuclei at ∼ 130 keV

Author

K. Todoroki, L. Venturelli, M. Prest, Masaki Hori, Valerio Mascagna, E. Lodi-Rizzini, D. Barna, Nicola Zurlo, Hossein Aghai-Khozani, M. Leali, E. Vallazza, Ryugo S. Hayano, Anna Sótér, M. Corradini, and Takumi Kobayashi

Subjects
Mass number, Physics, Light nucleus, Particle physics, Annihilation, media_common.quotation_subject, Nuclear Theory, Theoretical models, General Physics and Astronomy, Asymmetry, Cosmology, Nuclear physics, Antiproton Decelerator, Antiproton, Nuclear Experiment, media_common
Abstract

The existing data of antinucleon-nucleon and antinucleon-nuclei annihilation cross-sections are confined to energies above about 1MeV. Experimental limitations have prevented till now the lower energies data to be achieved in spite of the interest they represent for theoretical models. One of the unresolved question concerns the antiproton annihilation cross-section measured at LEAR on light nuclei in the MeV region, which show a saturation with the mass number of the target nucleus against any naive expectation. With regard to fundamental cosmology, the knowledge of the annihilation cross-sections at energies below 1MeV can contribute to understand the matter-antimatter asymmetry in the Universe. We present here the experimental demonstration of the feasibility of the measurement of antiproton-nuclei annihilation cross-sections in the 100 keV region.

Published
2012

38. Meson spectroscopy withS- andP-wave-dominant initial-state selection in $$\bar pp$$ annihilationannihilation

Author

C. Guaraldo, G. Piragino, Felice Iazzi, D. Yu. Denisov, Paolo Montagna, Corrado Cicalo, P. Cerello, G. Maron, A. Bertin, Roberto Spighi, G. Belli, F. Tosello, S. Tessaro, Bruno Minetti, A. Filippi, A. Vitale, G.C. Bonazzola, G. Bendiscioli, E. Rossetto, Mauro Villa, Tullio Bressani, Paola Salvini, S.N. Prakhov, V. Filippini, M. Lombardi, M. Corradini, L. Fava, P. Boccaccio, U. Gastaldi, C. De Leo, F. Nichitiu, A. Lai, M. Capponi, S. De Castro, Marco Bruschi, G. Pauli, D. Panzieri, G. V. Margagliotti, Alessandro Feliciello, Benedetto Giacobbe, Antonietta Donzella, M.G. Sapozhnikov, A.M. Rozhdestvensky, L. Musa, L. Vannucci, Alberto Andrighetto, M. Morando, V.I. Tretyak, G. Puddu, N. Semprini Cesari, A. Maggiora, B. Cereda, S. Serci, L. Santi, V.G. Ableev, V. Lucherini, L. Ferrero, Massimo Piccinini, A. Grasso, L. Busso, E. Lodi Rizzini, M.P. Bussa, Alberto Rotondi, L. Venturelli, S. Costa, Stefania Vecchi, R. Garfagnini, R. A. Ricci, Umberto Marini Bettolo Marconi, Armando Lanaro, F. Balestra, A. Zenoni, Antonio Zoccoli, M. Poli, T. D. Galli, G. Vedovato, Paola Gianotti, Elena Botta, A. Adamo, I. Massa, S. Marcello, F. D'Isep, P.P. Temnikov, Gianfranco Zosi, Adriano Fontana, A. Saino, Michelangelo Agnello, Alberto Masoni, D. Calvo, and G. L. Usai

Subjects
Physics, Particle physics, Annihilation, Meson, Branching fraction, Nuclear Theory, Detector, State (functional analysis), Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment, Spectroscopy, Computer Science::Databases, Bar (unit)
Abstract

The possibility of selecting the initial angular-momentum state from which antiproton-proton annihilation at rest can occur can be a fundamental tool in meson spectroscopy. With the OBELIX detector different target systems have been employed, ranging fromS-wave toP-wave dominance. The preliminary results both on meson spectroscopy and branching ratio measurements are discussed.

Published
1994

39. Evidence of a new state at ∼ 1660 MeV/c2 observed in $$\bar np$$ annihilationsannihilations

Author

C. De Leo, L. Venturelli, S. Costa, Paolo Montagna, G. Puddu, D. Yu. Denisov, S.N. Prakhov, L. Fava, G.C. Bonazzola, Paola Salvini, Mauro Villa, R. Spighi, Bruno Minetti, Alberto Masoni, Maurizio Piccinini, S. De Castro, M.G. Sapozhnikov, G. Belli, D. Calvo, N. Semprini Cesari, A. Saino, L. Santi, E. Rossetto, M. Corradini, F. Nichitiu, V.G. Ableev, Armando Lanaro, M. Capponi, A. Maggiora, A. Grasso, G. Pauli, Antonietta Donzella, B. Giacobbe, Tullio Bressani, V. Lucherini, U. Gastaldi, L. Busso, Michelangelo Agnello, M. Poli, G. Vedovato, P. Cerello, Petar Temnikov, A. Bertin, B. Cereda, G. L. Usai, D. Panzieri, S. Serci, M. Lombardi, Paola Gianotti, G. Maron, L. Vannucci, A. Adamo, A. Filippi, Antonio Zoccoli, V. Filippini, T. D. Galli, F. Balestra, A.M. Rozhdestvensky, Marco Bruschi, E. Lodi Rizzini, Aldo Zenoni, I. Massa, S. Marcello, Felice Iazzi, F. D'Isep, Corrado Cicalo, Gianfranco Zosi, Adriano Fontana, M.P. Bussa, Stefania Vecchi, F. Tosello, S. Tessaro, U. Marconi, A. Vitale, R. Garfagnini, Elena Botta, M. Morando, V.I. Tretyak, C. Guaraldo, G. Piragino, G. Bendiscioli, G. V. Margagliotti, Alessandro Feliciello, L. Ferrero, Alberto Rotondi, R. A. Ricci, and P. Boccaccio

Subjects
Physics, Nuclear physics, Annihilation, Bar (music), Spectrum (functional analysis), High Energy Physics::Experiment, Invariant mass, State (functional analysis), Atomic physics, Nuclear Experiment
Abstract

A study of\(\bar np\) in-flight annihilations is presented. The 4π invariant mass spectrum resulting from the analysis of the five-prong exclusive events, following the annihilation of ∼ (100–297) MeV/c\(\bar n\), reveals, besides a large structure centred at ∼ 1500 MeV/c2, some evidences for a new state around 1660 MeV/c2.

Published
1994

40. Two-photon laser spectroscopy of antiprotonic helium and the antiproton-to-electron mass ratio

Author

D. Barna, B. Juhász, D Horváth, L. Venturelli, Andreas Dax, Ryugo S. Hayano, Eberhard Widmann, Anna Sótér, Masaki Hori, S. Friedreich, T. Pask, and N. Zurlo

Subjects
Atomic Physics (physics.atom-ph), FOS: Physical sciences, chemistry.chemical_element, Antiproton, Electron, Spectral line, Physics - Atomic Physics, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Exotic Atoms, Antiprotonic Helium, CPT symmetry, Laser Spectroscopy, Physics::Atomic Physics, Nuclear Experiment (nucl-ex), Spectroscopy, Nuclear Experiment, Antiprotonic helium, Helium, Exotic atom, Physics, Multidisciplinary, chemistry, Atomic physics, Doppler broadening
Abstract

Physical laws are believed to be invariant under the combined transformations of charge, parity and time reversal (CPT symmetry). This implies that an antimatter particle has exactly the same mass and absolute value of charge as its particle counterpart. Metastable antiprotonic helium ($\bar{p}{\rm He}^+$) is a three-body atom consisting of a normal helium nucleus, an electron in its ground state and an antiproton ($\bar{p}$) occupying a Rydberg state with high principal and angular momentum quantum numbers, respectively $n$ and $\ell$, such that $n\sim\ell\sim 38$. These atoms are amenable to precision laser spectroscopy, the results of which can in principle be used to determine the antiproton-to-electron mass ratio and to constrain the equality between the antiproton and proton charges and masses. Here we report two-photon spectroscopy of antiprotonic helium, in which $\bar{p}{\rm ^3He^+}$ and $\bar{p}{\rm ^4He^+}$ isotopes are irradiated by two counter-propagating laser beams. This excites nonlinear, two-photon transitions of the antiproton of the type $(n,\ell)\rightarrow (n-2,\ell-2)$ at deep-ultraviolet wavelengths ($\lambda$=139.8, 193.0 and 197.0nm), which partly cancel the Doppler broadening of the laser resonance caused by the thermal motion of the atoms. The resulting narrow spectral lines allowed us to measure three transition frequencies with fractional precisions of 2.3-5 parts in $10^9$. By comparing the results with three-body quantum electrodynamics calculations, we derived an antiproton-to-electron mass ratio of 1,836.1526736(23), where the parenthetical error represents one standard deviation. This agrees with the proton-to-electron value known to a similar precision.

Published
2011

41. Features of pi-induced collective resonances in nuclei A semi-empirical model for collective nuclear resonances in the Delta energy region

Author

T. Blokhintseva, Andrea Bianconi, R. Garfagnini, V.A. Drozdov, M. Artoni, I. Gnesi, A. Kirilov, M. Corradini, F. Tosello, G. Piragino, B. Parsamyan, I. A. Belolaptikov, G.B. Pontecorvo, M. L. Colantoni, A. Grasso, V. I. Lyashenko, A. Moiseenko, S. Baginyan, E. Lodi Rizzini, V.A. Panyushkin, V.V. Ivanov, Vladimir Frolov, D. Panzieri, Yu.A. Batusov, M. Chiosso, N. Russakovich, Gianfranco Zosi, A.M. Rozhdestvensky, Enrico Scalas, A. Dem’yanov, N. Angelov, V. Grebenyuk, P. Batyuk, F. Balestra, L. Venturelli, M. Schepkin, A. Maggiora, and V M Kovalenko

Subjects
Elastic scattering, Physics, Nuclear and High Energy Physics, PIONS, K+ COLLISIONS, Nuclear Theory, Hadron, Binding energy, XE NUCLEI, Nuclear structure, Nuclear matter, NARROW BARYON RESONANCE, TOTAL CROSS-SECTIONS, POSITIVE STRANGENESS, SCATTERING, HE-4, Excited state, Nuclear fusion, Atomic physics, Nuclear Experiment, Nucleon
Abstract

A semi-empirical model is presented for the excitation of collective nuclear resonances induced by pions on nuclei in the Δ(1232) energy region. The physical features of the collective states have been extracted according to the model by fitting data from a collection of resonant π-nucleus elastic scattering cross-sections. The contributions to the total binding energy and to the width of a collective state per each additional nucleon involved in the resonance have been extracted. The interaction between the collective resonances and the surrounding nuclear medium is discussed.

Published
2011

42. Measurement of the antiproton-nucleus annihilation cross-section at very low energies

Author

Valerio Mascagna, E. Lodi Rizzini, Masaki Hori, A. Mozzanica, M. Corradini, E. Vallazza, M. Leali, M. Prest, Nicola Zurlo, and L. Venturelli

Subjects
Antiparticle, Particle physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Annihilation, Antiproton, Nuclear physics, Atomic and Molecular Physics, Nuclear, Physics::Atomic Physics, Physical and Theoretical Chemistry, Antihydrogen, Nuclear Experiment, Antiprotonic helium, Physics, Cross section, Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Antiproton Decelerator, Antimatter, Physics::Accelerator Physics, High Energy Physics::Experiment, and Optics, Nucleon
Abstract

The main fields of investigation of the ASACUSA Experiment at the Antiproton Decelerator at CERN concern test of CPT violation through spectroscopy of antihydrogen and antiprotonic helium, atomic collision and nuclear physics experiments. The nuclear physics program foresees measurements of p-nuclei cross sections at low energies (from few MeV down to the keV region) using a cylindrical detector with 6 layers of scintillating fibers surrounding the target. These measurements will contribute to understand the dynamic of the annihilation process and in particular to explain why the antiproton-nucleus annihilation rate at very low energy appears independent from the size of the target, as measured by the Obelix Collaboration at CERN for H, D and He. The preliminary results of the measurements performed during 2008 are presented.

Published
2009

43. Protonium production in ATHENA

Author

P. Genova, E. Lodi Rizzini, H.S. Pruys, V. Lagomarsino, C. Regenfus, Nicola Zurlo, Niels Madsen, C. Carraro, M. Charlton, G. Manuzio, G. Testera, L. G. C. Posada, R. Funakoshi, Michael Doser, C. L. Cesar, L. V. Jørgensen, M. Amoretti, Ryugo S. Hayano, Germano Bonomi, Alessandro Variola, M. Macri, D. P. van der Werf, R. Landua, D. Mitchard, P. Montagna, Claude Amsler, L. Venturelli, Alban Kellerbauer, Yasunori Yamazaki, Alberto Rotondi, and Adriano Fontana

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Dihydrogen cation, Penning trap, Nuclear physics, Protonium, Antiproton, Antimatter, Atom, Physics::Accelerator Physics, Physics::Atomic Physics, Atomic physics, Nuclear Experiment, Antihydrogen, Instrumentation
Abstract

The ATHENA experiment at CERN, after producing cold antihydrogen atoms for the first time in 2002, has synthesised protonium atoms in vacuum at very low energies. Protonium, i.e. the antiproton–proton bound system, is of interest for testing fundamental physical theories. In the nested penning trap of the ATHENA apparatus protonium has been produced as result of a chemical reaction between an antiproton and the simplest matter molecule, H 2 + . The formed protonium atoms have kinetic energies in the range 40–700 meV and are metastable with mean lifetimes of the order of 1 μs. Our result shows that it will be possible to start measurements on protonium at low energy antiproton facilities, such as the AD at CERN or FLAIR at GSI.

Published
2007

44. On the chemical reaction of matter with antimatter

Author

L. Venturelli, Evandro Lodi Rizzini, and N. Zurlo

Subjects
Physics, Hydrogen atom, Penning trap, Atomic and Molecular Physics, and Optics, Ion, Antiproton, Protonium, Antimatter, Excited state, Elementary reaction, Physics::Atomic Physics, Physical and Theoretical Chemistry, Atomic physics, Nuclear Experiment
Abstract

A chemical reaction between the building block antiatomic nucleus, the antiproton (p or H- in chemical notation), and the hydrogen molecular ion (H2+) has been observed by the ATHENA collaboration at CERN. The charged pair interact via the long-range Coulomb force in the environment of a Penning trap which is purpose-built to observe antiproton interactions. The net result of the very low energy collision of the pair is the creation of an antiproton-proton bound state, known as protonium (Pn), together with the liberation of a hydrogen atom. The Pn is formed in a highly excited, metastable, state with a lifetime against annihilation of around 1 micros. Effects are observed related to the temperature of the H2+ prior to the interaction, and this is discussed herein.

Published
2007

45. Evidence For The Production Of Slow Antiprotonic Hydrogen In Vacuum

Author

M. Macri, E. Lodi Rizzini, L. Venturelli, G. Testera, M. Amoretti, D. P. van der Werf, Michael Doser, Alban Kellerbauer, Niels Madsen, R. Landua, D. Mitchard, Ryugo S. Hayano, P. Montagna, L. G. C. Posada, Germano Bonomi, M. Charlton, V. Lagomarsino, Yasunori Yamazaki, C. Regenfus, Adriano Fontana, L. V. Jørgensen, P. Genova, Claude Amsler, Alessandro Variola, Alberto Rotondi, N. Zurlo, H.S. Pruys, C. Carraro, R. Funakoshi, C. L. Cesar, and G. Manuzio

Subjects
Physics, Annihilation, Hydrogen, Polyatomic ion, FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Penning trap, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), chemistry, Antiproton, Physics::Accelerator Physics, High Energy Physics::Experiment, Physics::Atomic Physics, Atomic physics, Nuclear Experiment, Antihydrogen, Antiprotonic helium, Particle Physics - Experiment, Hydrogen production
Abstract

We present evidence showing how antiprotonic hydrogen, the quasistable antiproton-proton (pbar-p) bound system, has been synthesized following the interaction of antiprotons with the hydrogen molecular ion (H2+) in a nested Penning trap environment. From a careful analysis of the spatial distributions of antiproton annihilation events, evidence is presented for antiprotonic hydrogen production with sub-eV kinetic energies in states around n=70, and with low angular momenta. The slow antiprotonic hydrogen may be studied using laser spectroscopic techniques., 5 pages with 4 figures. Published as Phys. Rev. Letters 97, 153401 (2006), in slightly different form

Published
2006

46. On the muon neutrino mass

Author

Yu.A. Batusov, N.S. Angelov, L. Busso, F. Balestra, I. Gnesi, L. Ferrero, L. Venturelli, G. B. Pontecorvo, R. Garfagnini, Andrea Bianconi, G. Piragino, D. Panzieri, E. Lodi Rizzini, F. Tosello, M.P. Bussa, and A. Maggiora

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Muon, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Nuclear physics, LIGHT-NUCLEI, Pion, Measurements of neutrino speed, Physics::Accelerator Physics, Muon neutrino, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Neutrino, Neutrino oscillation, CHAMBER, Electron neutrino, Nuclear Experiment, Lepton, Nuclear Physics
Abstract

During the runs of the PS 179 experiment at LEAR of CERN, we photographed an event of antiproton-Ne absorption, with a complete pi+ -> mu+ ->e+ chain. From the vertex of the reaction a very slow energy pi+ was emitted. The pi+ decays into a mu+ and subsequently the mu+ decays into a positron. At the first decay vertex a muon neutrino was emitted and at the second decay vertex an electron neutrino and a muon antineutrino. Measuring the pion and muon tracks and applying the momentum and energy conservation and using a classical statistical interval estimator, we obtained an experimental upper limit for the muon neutrino mass: m_nu < 2.2 MeV at a 90% confidence level. A statistical analysis has been performed of the factors contributing to the square value of the neutrino mass limit., 18 pages, 5 eps figures

Published
2006

47. Sideband cooling of ions in a non-neutral buffer gas

Author

P. Genova, L. Venturelli, Niels Madsen, Alban Kellerbauer, D. P. van der Werf, C. L. Cesar, V. Lagomarsino, C. Carraro, M. C. Fujiwara, Germano Bonomi, D. Mitchard, P. Montagna, R. Landua, I. Johnson, Alessandro Variola, R. Funakoshi, Adriano Fontana, M. Amoretti, L. G. C. Posada, Carlo Canali, M. Charlton, Nicola Zurlo, Alberto Rotondi, Yasunori Yamazaki, M. Macri, P. D. Bowe, L. V. Jørgensen, Ryugo S. Hayano, G. Testera, Michael Doser, and E. Lodi Rizzini

Subjects
Physics, Sideband, Buffer gas, Cryogenics, Penning trap, Atomic and Molecular Physics, and Optics, Ion, Antiproton Decelerator, Antiproton, Physics::Accelerator Physics, Physics::Atomic Physics, Atomic physics, Nuclear Experiment, Fermi gas
Abstract

We have investigated an extension of the buffer gas cooling technique to a non-neutral buffer gas. The proposed scheme will allow efficient mass-selective centering of ions confined in a Penning trap in situations where the use of a neutral damping agent is not possible. The present paper reviews the principle of the technique and reports on evidence for sideband cooling of antiprotons in an electron gas, obtained with the ATHENA apparatus at CERN's Antiproton Decelerator facility.

Published
2006

48. Production of slow protonium in vacuum

Author

Alban Kellerbauer, D. Mitchard, Adriano Fontana, P. Montagna, Yasunori Yamazaki, M. Amoretti, C. Carraro, M. Macri, P. Genova, G. Testera, L. Venturelli, L. G. C. Posada, R. Landua, R. Funakoshi, Alessandro Variola, Alberto Rotondi, N. Zurlo, C. L. Cesar, H. Pruys, Germano Bonomi, G. Manuzio, L. V. Jørgensen, M. Doser, Ryugo S. Hayano, E. Lodi Rizzini, V. Lagomarsino, C. Regenfus, Niels Madsen, M. Charlton, D. P. van der Werf, and Claude Amsler

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Work (thermodynamics), Annihilation, Polyatomic ion, FOS: Physical sciences, Condensed Matter Physics, Laser, Kinetic energy, Penning trap, Atomic and Molecular Physics, and Optics, High Energy Physics - Experiment, law.invention, Nuclear physics, High Energy Physics - Experiment (hep-ex), Antiproton, law, Protonium, Physics::Atomic Physics, Physical and Theoretical Chemistry, Nuclear Experiment, Particle Physics - Experiment
Abstract

We describe how protonium, the quasi-stable antiproton-proton bound system, has been synthesized following the interaction of antiprotons with the molecular ion H$_2^+$ in a nested Penning trap environment. From a careful analysis of the spatial distributions of antiproton annihilation events in the ATHENA experiment, evidence is presented for protonium production with sub-eV kinetic energies in states around $n$ = 70, with low angular momenta. This work provides a new 2-body system for study using laser spectroscopic techniques., Comment: 9 pages with 5 figures and 1 table. Proceedings of the 4th International Conference on Trapped Charged Particles and Fundamental Physics (TCP 06), published in Hyperfine Interactions

Published
2006

49. Spin physics with antiprotons

Author

M. Maggiora, V. Abazov, G. Alexeev, M. Alexeev, A. Amoroso, N. Angelov, S. Baginyan, F. Balestra, V. A. Baranov, Yu. Batusov, I. Belolaptikov, R. Bertini, A. Bianconi, R. Birsa, T. Blokhintseva, A. Bonyushkina, F. Bradamante, A. Bressan, M. P. Bussa, V. Butenko, M. Colantoni, M. Corradini, S. Dalla Torre, A. Demyanov, O. Denisov, V. Drozdov, J. Dupák, G. Erusalimtsev, L. Fava, A. Ferrero, L. Ferrero, M. Finger, V. Frolov, R. Garfagnini, M. Giorgi, V. A. Kalinnikov, Yu. Kharzheev, N. V. Khomutov, A. Kirilov, Yu. Kisselev, E. Komissarov, A. S. Korenchenko, A. Kotzinian, V. Kovalenko, N. P. Kravchuk, N. A. Kuchinski, E. Lodi Rizzini, V. Lyashenko, A. Maggiora, V. Malyshev, A. Martin, Yu. Merekov, A. S. Moiseenko, A. Olchevski, V. Panyushkin, D. Panzieri, G. Piragino, G. B. Pontecorvo, A. Popov, S. Porokhovoy, V. Pryanichnikov, M. Radici, M. P. Rekalo, A. Rozhdestvensky, N. Russakovich, P. Schiavon, O. Shevchenko, A. Shishkin, V. A. Sidorkin, N. Skachkov, M. Slunecka, A. Srnka, V. Tchalyshev, F. Tessarotto, E. Tomasi-Gustafsson, F. Tosello, E. P. Velicheva, L. Venturelli, L. Vertogradov, M. Virius, G. Zosi, and N. Zurlo

Subjects
Physics, Particle physics, High Energy Physics::Phenomenology, Nuclear Theory, Hyperon, FOS: Physical sciences, General Physics and Astronomy, Parton, Function (mathematics), High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Distribution function, Antiproton, High Energy Physics::Experiment, Open charm, Nucleon, Spin (physics), Nuclear Experiment
Abstract

New possibilities arising from the availability at GSI of antiproton beams, possibly polarised, are discussed. The investigation of the nucleon structure can be boosted by accessing in Drell-Yan processes experimental asymmetries related to cross-sections in which the parton distribution functions (PDF) only appear, without any contribution from fragmentation functions; such processes are not affected by the chiral suppression of the transversity function $h_1(x)$. Spin asymmetries in hyperon production and Single Spin Asymmetries are discussed as well, together with further items like electric and magnetic nucleonic form factors and open charm production. Counting rates estimations are provided for each physical case. The sketch of a possible experimental apparatus is proposed., Presented for the proceedings of ASI "Spin and Symmetry", Prague, July 5-10, 2004, to be published in Czech. J. Phys. 55 (2005)

Published
2005

50. Antiproton-nucleus annihilation at very low energies down to capture

Author

E. Lodi Rizzini, M. Leali, Antonio Bianconi, M. Corradini, L. Venturelli, and Nicola Zurlo

Subjects
Nuclear reaction, Physics, Antiparticle, Particle physics, Large Hadron Collider, Annihilation, Physics::Instrumentation and Detectors, Baryon, Nuclear physics, Antiproton, Antimatter, Physics::Accelerator Physics, High Energy Physics::Experiment, Physics::Atomic Physics, Nuclear Experiment, Nucleon
Abstract

Results and opportunities at the low energies antiproton facilities at CERN (AD) are presented.

Published
2005

Catalog

Books, media, physical & digital resources
See catalog results