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101. Temporally Controlled Modulation of Antihydrogen Production and the Temperature Scaling of Antiproton-Positron Recombination

Author

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

Subjects
Physics, General Physics and Astronomy, Pulse duration, Plasma, Penning trap, Accelerators and Storage Rings, Nuclear physics, Positron, Antiproton, Antimatter, Physics::Accelerator Physics, Plasma diagnostics, Physics::Atomic Physics, Atomic physics, Antihydrogen
Abstract

We demonstrate temporally controlled modulation of cold antihydrogen production by periodic RF heating of a positron plasma during antiproton-positron mixing in a Penning trap. Our observations have established a pulsed source of atomic antimatter, with a rise time of about 1 s, and a pulse length ranging from 3 to 100 s. Time-sensitive antihydrogen detection and positron plasma diagnostics, both capabilities of the ATHENA apparatus, allowed detailed studies of the pulsing behavior, which in turn gave information on the dependence of the antihydrogen production process on the positron temperature T. Our data are consistent with power law scaling T (-1.1+/-0.5) for the production rate in the high temperature regime from approximately 100 meV up to 1.5 eV. This is not in accord with the behavior accepted for conventional three-body recombination.

Published
2008

103. ASACUSA STATUS REPORT ASACUSA progress during 2006 and plans for 2007 ASACUSA collaboration

Author

H H Andersen, D Barna, M Charlton, M Corradini, A Dax, J Eades, Y Enomoto, R S Hayano, H Higaki, M Hori, D Horváth, T Ichioka, H Imao, B Juhász, Y Kanai, H Knudsen, P Kristiansen, N Kuroda, M Leali, E Lodi-Rizzini, C Malbrunot, B Mccollough, S P Møller, A Mohri, A Mozzanica, Y Nagata, N Ono, T Pask, W Pirkl, A Puhm, H Saito, K Tokesi, H A Torii, U Uggerhøj, V L Varentsov, L Venturelli, E Widmann, Y Yamazaki, Z Yoshida, P Zalan, and N Zurlo

Published
2007
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104. 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

105. FAST: A scintillating fiber tracker for antiprotons annihilation detection

Author

Davide Bolognini, L. Venturelli, Nicola Zurlo, A. Mozzanica, M. Corradini, E. Vallazza, M. Prest, M. Leali, and E. Lodi Rizzini

Subjects
Very-large-scale integration, Physics, Nuclear and High Energy Physics, Scintillation, Annihilation, Large Hadron Collider, Physics::Instrumentation and Detectors, Detector, Antiproton annihilation cross section, Nuclear physics, Antiproton Decelerator, Antiproton, Fiber, scintillating fibers, tracker, Instrumentation
Abstract

A new fiber detector has been developed for the measurement of the annihilation cross-section of slow antiprotons (5 MeV for the 2006 run, 1 keV in 2007) in gaseous targets in the framework of the ASACUSA experiment at the AD Antiproton Decelerator at CERN. The cylindrical gaseous target, 10 cm in radius, is surrounded by 2 axial and 4 stereo scintillating fiber layers built with 1 mm BCF-10 fibers from Bicron. The scintillation light released by charged pions originating in the annihilation vertex is readout by 64 channel multianode PMTs produced by HAMAMATSU. The anode outputs are amplified and discriminated with VLSI ASICs manufactured by IDEAS (VA64TAP2.1) and then sampled with a 320 MHz clock in order to extract the hit and time information by a set of ALTERA FPGAs. The paper describes the detector assembly, the custom electronics readout chain and the results of the tests during the commissioning phase.

Published
2007

106. Positron plasma control techniques for the production of cold antihydrogen

Author

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

Subjects
Physics, Range (particle radiation), Hydrogen, chemistry.chemical_element, Plasma, Atomic and Molecular Physics, and Optics, Ion, Positron, chemistry, Production (computer science), Plasma diagnostics, Atomic physics, Antihydrogen, Particle Physics - Experiment
Abstract

An observation of a clear dependence of antihydrogen production on positron plasma shapes is reported. For this purpose a plasma control method has been developed combining the plasma rotating-wall technique with a mode diagnostic system. With the help of real-time and nondestructive observations, the rotating-wall parameters have been optimized. The positron plasma can be manipulated into a wide range of shapes (aspect ratio 6.5{

Published
2007

107. New data on OZI rule violation in annihilation at rest

Author

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

Subjects
Physics, Rest (physics), Nuclear physics, Nuclear and High Energy Physics, Particle physics, PHI-MESON PRODUCTION, ANTIPROTON ANNIHILATION, Annihilation, OZI rule, Antiproton, Momentum transfer
Abstract

The results of measuring the ratio R = Y(φπ + π − ) Y(ωπ + π − ) for antiproton annihilation at rest in a gaseous and a liquid hydrogen target are presented. It was found that the value of this ratio increases with the decrease of the dipion mass, which demonstrates the difference between the φ and ω production mechanisms. An indication of the momentum transfer dependence of the apparent OZI rule violation for the φ production from the 3S1 initial state was found.

Published
1996

108. 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

109. 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

110. Search for Laser-Induced Formation of Antihydrogen Atoms

Author

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

Subjects
Physics, Hydrogen, General Physics and Astronomy, chemistry.chemical_element, Penning trap, Laser, law.invention, chemistry, Antiproton, Quantum state, law, Physics::Atomic and Molecular Clusters, Continuous wave, Spontaneous emission, Physics::Atomic Physics, Atomic physics, Antihydrogen, Particle Physics - Experiment
Abstract

Antihydrogen can be synthesized by mixing antiprotons and positrons in a Penning trap environment. Here an experiment to stimulate the formation of antihydrogen in the n = 11 quantum state by the introduction of light from a CO2 continuous wave laser is described. An overall upper limit of 0.8% with 90% C.L. on the laser-induced enhancement of the recombination has been found. This result strongly suggests that radiative recombination contributes negligibly to the antihydrogen formed in the experimental conditions used by the ATHENA Collaboration.

Published
2006

111. 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

112. Design and prototype results of the FAST detector

Author

M. Basset, Nicola Zurlo, L. Venturelli, M. Prest, A. Mozzanica, M. Corradini, E. Vallazza, M. Leali, Massimo Caccia, and E. Lodi Rizzini

Subjects
Physics, Nuclear and High Energy Physics, Photomultiplier, Large Hadron Collider, Optical fiber, Physics::Instrumentation and Detectors, business.industry, Detector, Antiprotons, Tracking (particle physics), law.invention, Nuclear physics, Antiproton Decelerator, scintillating fibers, tracker, Optics, Antiproton, law, High Energy Physics::Experiment, business, Instrumentation, Image resolution
Abstract

A new fiber tracker is being developed for the ASACUSA experiment at the Antiproton Decelerator at CERN. The detector is based on 1 mm diameter scintillating fibers readout by HAMAMATSU 64 channel multianode photomultipliers (MA-PMTs) connected to a dedicated electronic chain. The paper gives a description of the testing procedures for time resolution, spatial resolution and efficiency measurements performed with standard NIM electronics and a commercial TDC and reports the results for different prototype detectors.

Published
2006

113. 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

114. Progress with cold antihydrogen

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Large Hadron Collider, Penning trap, Antiproton Decelerator, Nuclear physics, Antiproton, Antimatter, Physics::Atomic and Molecular Clusters, Physics::Accelerator Physics, Physics::Atomic Physics, Formation rate, Antihydrogen, Instrumentation
Abstract

The creation of cold antihydrogen by the ATHENA and ATRAP collaborations, working at CERN’s unique Antiproton Decelerator (AD) facility, has ushered in a new era in atomic physics. This contribution will briefly review recent results from the ATHENA experiment. These include discussions of antiproton slowing down in a cold positron gas during antihydrogen formation, information derived on the dependence of the antihydrogen formation rate upon the temperature of the stored positron plasma and, finally, upon the spatial distribution of the emitted anti-atoms. We will discuss the implications of these studies for the major outstanding goal of trapping samples of antihydrogen for precise spectroscopic comparisons with hydrogen. The physics motivations for undertaking these challenging experiments will be briefly recalled.

Published
2006

115. 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

116. Spatial distribution of cold antihydrogen formation

Author

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

Subjects
Physics, Physics::General Physics, Annihilation, General Physics and Astronomy, Plasma, Penning trap, XX, Nuclear physics, Positron, Physics::Plasma Physics, Ultracold atom, Antiproton, Antimatter, Physics::Atomic and Molecular Clusters, High Energy Physics::Experiment, Physics::Atomic Physics, Atomic physics, Antihydrogen
Abstract

Antihydrogen is formed when antiprotons are mixed with cold positrons in a nested Penning trap. We present experimental evidence, obtained using our antihydrogen annihilation detector, that the spatial distribution of the emerging antihydrogen atoms is independent of the positron temperature and axially enhanced. This indicates that antihydrogen is formed before the antiprotons are in thermal equilibrium with the positron plasma. This result has important implications for the trapping and spectroscopy of antihydrogen.

Published
2005

117. New Source of Dense, Cryogenic Positron Plasmas

Author

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

Subjects
Base (group theory), Physics, Positron, Low magnetic field, Electric field, General Physics and Astronomy, Plasma, High field, Orders of magnitude (numbers), Atomic physics, XX, Magnetic field
Abstract

We have developed a new method, based on the ballistic transfer of preaccumulated plasmas, to obtain large and dense positron plasmas in a cryogenic environment. The method involves transferring plasmas emanating from a region with a low magnetic field (0.14 T) and relatively high pressure (${10}^{\ensuremath{-}9}\text{ }\text{ }\mathrm{mbar}$) into a 15 K Penning-Malmberg trap immersed in a 3 T magnetic field with a base pressure better than ${10}^{\ensuremath{-}13}\text{ }\text{ }\mathrm{mbar}$. The achieved positron accumulation rate in the high field cryogenic trap is more than one and a half orders of magnitude higher than the previous most efficient UHV compatible scheme. Subsequent stacking resulted in a plasma containing more than $1.2\ifmmode\times\else\texttimes\fi{}{10}^{9}$ positrons, which is a factor 4 higher than previously reported. Using a rotating wall electric field, plasmas containing about $20\ifmmode\times\else\texttimes\fi{}{10}^{6}$ positrons were compressed to a density of $2.6\ifmmode\times\else\texttimes\fi{}{10}^{10}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$. This is a factor of 6 improvement over earlier measurements.

Published
2005

118. 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

119. Study of the OZI-rule violation in antiproton annihilation in deuterium at rest

Author

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

Subjects
Physics, Particle physics, Annihilation, OZI-RULE, High Energy Physics::Phenomenology, antiproton deuterium annihilation, OZI rule, Nuclear physics, Deuterium, ANTIPROTON ANNIHILATION, Antiproton, High Energy Physics::Experiment, Physics::Atomic Physics, Nuclear Experiment
Abstract

The branching ratios of Φπ− and ωπ− final states were measured for the antiproton annihilation in gaseous deuterium at rest. A significant violation of the OZI rule was found.

Published
1994

120. Changes in the Annihilation’s delay time distribution of stopped antiprotons in helium gas, due to contaminants.—I

Author

V. G. Ableev, 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, B. Cereda, P. Cerello, C. Cicalo, M. Corradini, S. Costa, S. Castro, O. Y.u. Denisov, F. D’Isep, A. Donzella, L. Fava, A. Feliciello, L. Ferrero, A. Filippi, V. Filippini, D. Galli, R. Garfagnini, U. Gastaldi, B. Giacobbe, P. Gianotti, A. Grasso, C. Guaraldo, F. Iazzi, A. Lai, A. Lanaro, E. Lodi Rizzini, M. Lombardi, V. Lucherini, A. Maggiora, S. Marcello, U. Marconi, G. Maron, A. Masoni, I. Massa, B. Minetti, P. Montagna, M. Morando, L. Musa, F. Nichitiu, D. Panzieri, G. Pauli, M. Piccinini, G. Piragino, M. Poli, S. N. Prakhov, G. Puddu, R. A. Ricci, C. Rizzo, E. Rossetto, A. Rotondi, A. M. Rozhdestvensky, P. Salvini, L. Santi, M. G. Sapozhnikov, N. Semprini Cesari, S. Serci, R. Spighi, P. Temnikov, F. Tosello, V. I. Tretyak, G. L. Usai, L. Vannucci, S. Vecchi, G. Vedovato, L. Venturelli, M. Villa, A. Vitale, E. Zavattini, A. Zenoni, A. Zoccoli, G. Zosi, MARGAGLIOTTI, GIACOMO, TESSARO, SUSANNA, V. G., Ableev, 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, B., Cereda, P., Cerello, C., Cicalo, M., Corradini, S., Costa, S., Castro, Denisov, O. Y. u., F., D’Isep, A., Donzella, L., Fava, A., Feliciello, L., Ferrero, A., Filippi, V., Filippini, D., Galli, R., Garfagnini, U., Gastaldi, B., Giacobbe, P., Gianotti, A., Grasso, C., Guaraldo, F., Iazzi, A., Lai, 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, P., Montagna, M., Morando, L., Musa, F., Nichitiu, D., Panzieri, G., Pauli, M., Piccinini, G., Piragino, M., Poli, S. N., Prakhov, G., Puddu, R. A., Ricci, C., Rizzo, E., Rossetto, A., Rotondi, A. M., Rozhdestvensky, P., Salvini, L., Santi, M. G., Sapozhnikov, N., Semprini Cesari, S., Serci, R., Spighi, P., Temnikov, Tessaro, Susanna, F., Tosello, V. I., Tretyak, G. L., Usai, L., Vannucci, S., Vecchi, G., Vedovato, L., Venturelli, M., Villa, A., Vitale, E., Zavattini, A., Zenoni, A., Zoccoli, and G., Zosi

Subjects
Physics, Quenching, Annihilation, Antiproton-induced reactions, Hydrogen, chemistry.chemical_element, Nanosecond, Neon, Xenon, chemistry, Antiproton, Atomic physics, Bar (unit)
Abstract

The effect of contaminants (H2, N2, Ne, Ar, Xe) on the time distribution of delayed annihilations (average delay time about 3 μs) of antiprotons stopped in helium gas, at 3 atm and room temperature, has been experimentally investigated. The annihilation rate is expressed in terms of an empirical «quenching cross-section»,\(\bar \sigma \), that is different for the different contaminants. For hydrogen and xenon at low concentrations,\(\bar \sigma \) is around 3.5·10−16 cm2, and is more than ten times larger than for the other contaminants. It has been observed that the addition of a contaminant, with the exception of neon, gives also rise to a delayed annihilation’s component that decays with an average time of some hundreds of nanoseconds. It seems that this fast component increases and its average time decreases as the contaminant concentration increases.

Published
1994

121. First results from OBELIX on reactions with detected neutral pions in the final state

Author

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

Subjects
Physics, antinucleon-nucleon interaction, Particle physics, Annihilation, Spectrometer, Hydrogen, Physics::Instrumentation and Detectors, Branching fraction, antinucleon-nucleon interactions, chemistry.chemical_element, State (functional analysis), Calorimeter, Nuclear physics, Electromagnetic calorimeter, π K and η mesons, chemistry, High Energy Physics::Experiment, Bar (unit)
Abstract

We describe some results obtained by the OBELIX experiment at LEAR by exploiting the whole spectrometer, including the electromagnetic calorimeter, to study the antiproton-proton annihilation at rest in an NTP hydrogen target. In particular, we give some information on the calibration of the calorimeter, as obtained from the analysis of two-prong events, and we describe the status of the analysis of the first sample of «all neutrals» events collected in gaseous hydrogen. A preliminary result on the branching ratio of the annihilation reaction\(\bar pp \to \pi ^0 \pi ^0 \) is reported.

Published
1994

122. Measurement of the (anti)p-pi+pi and (anti)p-K+K- annihilation frequencies in a 5 mb hydrogen gas target

Author

V. G. Ableev, A. Adamo, M. Agnello, A. Andrighetto, 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, P. Cerello, C. Cicalo, M. Corradini, S. Costa, I. D'Antone, S. De Castro, F. D'Isep, A. Donzella, L. Fava, A. Feliciello, L. Ferrero, A. Filippi, V. Filippini, D. Galli, R. Garfagnini, U. Gastaldi, P. Gianotti, A. Grasso, C. Guaraldo, F. Iazzi, A. Lai, A. Lanaro, E. Lodi Rizzini, M. Lombardi, V. Lucherini, A. Maggiora, G. Maneva, S. Marcello, U. Marconi, G. Maron, A. Masoni, I. Massa, B. Minetti, M. Morando, P. Montagna, L. Musa, 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, R. Spighi, S. Vecchi, P. Temnikov, S. Tessaro, F. Tosello, V. I. Tretyak, G. Usai, L. Vannucci, G. Vedovato, L. Venturelli, M. Villa, A. Vitale, A. Zenoni, A. Zoccoli, G. Zosi, MARGAGLIOTTI, GIACOMO, V. G., Ableev, A., Adamo, M., Agnello, A., Andrighetto, 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, P., Cerello, C., Cicalo, M., Corradini, S., Costa, I., D'Antone, S., De Castro, F., D'Isep, A., Donzella, L., Fava, A., Feliciello, L., Ferrero, A., Filippi, V., Filippini, D., Galli, R., Garfagnini, U., Gastaldi, P., Gianotti, A., Grasso, C., Guaraldo, F., Iazzi, A., Lai, A., Lanaro, E., Lodi Rizzini, M., Lombardi, V., Lucherini, A., Maggiora, G., Maneva, S., Marcello, U., Marconi, Margagliotti, Giacomo, G., Maron, A., Masoni, I., Massa, B., Minetti, M., Morando, P., Montagna, L., Musa, 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, R., Spighi, S., Vecchi, P., Temnikov, S., Tessaro, F., Tosello, V. I., Tretyak, G., Usai, L., Vannucci, G., Vedovato, L., Venturelli, M., Villa, A., Vitale, A., Zenoni, A., Zoccoli, and G., Zosi

Subjects
BRANCHING RATIOS, K+K
Abstract

We report the first measurement of the K+K-, pi+pi- frequencies for pBAR annihilations at rest in a gaseous H-2 target at low pressure (5 mbar). We have obtained:f(pipi)=(4.26+/-0.11) X 10(-3), f(KK)=(0.46+/-0.03)X10(-3). The ratio R=f(KK)/f(pipi) has also been measured at a pressure of 2 mbar. Comparison with previous measurements shows that f(KK) decreases monotonically with the target density but its value at 5 mbar is still higher than the value with L X-rays in coincidence.

Published
1994

123. The φπ+/ωπ+ ratio from anti-np annihilations

Author

A. Adamo, M. Agnello, F. Balestra, G. Bendiscioli, A. Bertin, P. Boccaccio, G. C. Bonazzola, T. Bressani, M. Bruschi, M. P. Bussa, L. Busso, D. Calvo, M. Capponi, B. Cereda, P. Cerello, C. Cicalò, S. Costa, S. Castro, F. D’Isep, L. Fava, A. Feliciello, L. Ferrero, A. Filippi, V. Filippini, D. Galli, R. Garfagnini, U. Gastaldi, B. Giacobbe, 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, P. Montagna, M. Morando, 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. Usai, L. Vannucci, S. Vecchi, G. Vedovato, L. Venturelli, M. Villa, A. Vitale, A. Zenoni, A. Zoccoli, G. Zosi, L.Montanet and G.Preparata, A., Adamo, M., Agnello, F., Balestra, G., Bendiscioli, A., Bertin, P., Boccaccio, G. C., Bonazzola, T., Bressani, M., Bruschi, M. P., Bussa, L., Busso, D., Calvo, M., Capponi, B., Cereda, P., Cerello, C., Cicalò, S., Costa, S., Castro, F., D’Isep, L., Fava, A., Feliciello, L., Ferrero, A., Filippi, V., Filippini, D., Galli, R., Garfagnini, U., Gastaldi, B., Giacobbe, 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, P., Montagna, M., Morando, 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., Usai, L., Vannucci, S., Vecchi, G., Vedovato, L., Venturelli, M., Villa, A., Vitale, A., Zenoni, A., Zoccoli, and G., Zosi

Subjects
Mesons and meson resonance, Mesons and meson resonances, Hadron-induced low- and intermediate-energy reactions and scattering (energy≤10 GeV)
Abstract

A preliminary study of n¯p three-prong annihilations into the channels K− K+ π+ and π− π+ π+ π0 is presented for ∼ 100–297 MeV/c n¯ momenta. The extracted φπ+/ωπ+ production ratio shows that also in this channel, never measured before using an n¯p beam, the OZI rule is strongly violated.

Published
1994

124. ATHENA : First Production of Cold Antihydrogen and Beyond

Author

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

Subjects
Physics, Nuclear physics, Production (economics), Antihydrogen, Particle Physics - Experiment
Abstract

Atomic systems of antiparticles are the laboratories of choice for tests of CPT symmetry with antimatter. The ATHENA experiment was the first to report the production of copious amounts of cold antihydrogen in 2002. This article reviews some of the insights that have since been gained concerning the antihydrogen production process as well as the external and internal properties of the produced anti-atoms. Furthermore, the implications of those results on future prospects of symmetry tests with antimatter are discussed. Atomic systems of antiparticles are the laboratories of choice for tests of CPT symmetry with antimatter. The ATHENA experiment was the first to report the production of copious amounts of cold antihydrogen in 2002. This article reviews some of the insights that have since been gained concerning the antihydrogen production process as well as the external and internal properties of the produced anti-atoms. Furthermore, the implications of those results on future prospects of symmetry tests with antimatter are discussed. Atomic systems of antiparticles are the laboratories of choice for tests of CPT symmetry with antimatter. The ATHENA experiment was the first to report the production of copious amounts of cold antihydrogen in 2002. This article reviews some of the insights that have since been gained concerning the antihydrogen production process as well as the external and internal properties of the produced anti-atoms. Furthermore, the implications of those results on future prospects of symmetry tests with antimatter are discussed.

Published
2004

125. Three Dimensional Annihilation Imaging of Antiprotons in a Penning Trap

Author

P. Genova, Niels Madsen, L. V. Jørgensen, H.S. Pruys, M. Charlton, Ryugo S. Hayano, D. Lindelöf, Paolo Montagna, Alberto Rotondi, P. D. Bowe, P. Rielder, Alessandro Variola, E. Lodi Rizzini, J. S. Hangst, Germano Bonomi, M. Marchesotti, D. P. van der Werf, Adam Bouchta, Adriano Fontana, C. Regenfus, C. L. Cesar, C. Carraro, R. Landuad, V. Filippini, M. C. Fujiwara, R. Funakoshi, G. Testera, Michael Doser, M. Amoretti, M. Macri, and V. Lagomarsino

Subjects
Physics, Condensed Matter::Quantum Gases, Antiparticle, Annihilation, Particle loss, Other Fields of Physics, FOS: Physical sciences, Penning trap, Particle transport, Physics - Plasma Physics, High Energy Physics - Experiment, Trap (computing), Plasma Physics (physics.plasm-ph), High Energy Physics - Experiment (hep-ex), Physics - General Physics, General Physics (physics.gen-ph), Antiproton, Physics::Atomic Physics, Atomic physics, Nuclear Experiment (nucl-ex), Antihydrogen, Nuclear Experiment
Abstract

We demonstrate three-dimensional annihilation imaging of antiprotons trapped in a Penning trap. Exploiting unusual feature of antiparticles, we investigate a previously unexplored regime in particle transport; the proximity of the trap wall. Particle loss on the wall, the final step of radial transport, is observed to be highly non-uniform, both radially and azimuthally. These observations have considerable implications for the production and detection of antihydrogen atoms., Comment: Invited Talk at NNP03, Workshop on Non-Neutral Plasmas, 2003

Published
2004
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126. Three-Dimensional Annihilation Imaging of Trapped Antiprotons

Author

G. Manuzio, P. Montagna, C. L. Cesar, M. Macri, C. Carraro, V. Filippini, M. C. Fujiwara, R. Funakoshi, R. Landua, Adriano Fontana, Ryugo S. Hayano, V. Lagomarsino, D. P. van der Werf, G. Testera, G. Rouleau, Adam Bouchta, P. Genova, M. Amoretti, Niels Madsen, Michael Doser, Alberto Rotondi, L. V. Jørgensen, Alessandro Variola, J. S. Hangst, Petra Riedler, Yasunori Yamazaki, E. Lodi-Rizzini, P. D. Bowe, Germano Bonomi, M. Charlton, and M. Marchesotti

Subjects
Condensed Matter::Quantum Gases, Physics, Antiparticle, Annihilation, Particle loss, General Physics and Astronomy, XX, Penning trap, Symmetry (physics), Nuclear physics, Trap (computing), Antiproton, Physics::Atomic Physics, Nuclear Experiment, Antihydrogen
Abstract

We demonstrate three-dimensional imaging of antiprotons in a Penning trap, by reconstructing annihilation vertices from the trajectories of the charged annihilation products. The unique capability of antiparticle imaging has allowed, for the first time, the observation of the spatial distribution of the particle loss in a Penning trap. The radial loss of antiprotons on the trap wall is localized to small spots, strongly breaking the azimuthal symmetry expected for an ideal trap. Our observations have important implications for detection of antihydrogen annihilations.

Published
2004

127. Dynamics of antiproton cooling in a positron plasma during antihydrogen formation

Author

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

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Positron, Antiproton, Time evolution, Physics::Accelerator Physics, Physics::Atomic Physics, Plasma, Atomic physics, Penning trap, Antihydrogen
Abstract

We demonstrate cooling of 10 4 antiprotons in a dense, cold plasma of ∼10 8 positrons, confined in a nested cylindrical Penning trap at about 15 K. The time evolution of the cooling process has been studied in detail, and several distinct types of behavior identified. We propose explanations for these observations and discuss the consequences for antihydrogen production. We contrast these results with observations of interactions between antiprotons and “hot” positrons at about 3000 K, where antihydrogen production is strongly suppressed.

Published
2004

128. Real-time detector for plasma diagnostic in antimatter experiment

Author

Alessandro Variola, R. Landua, J. S. Hangst, Adam Bouchta, G. Manuzio, M. Charlton, M. Amoretti, M. Macri, D. P. van der Werf, C. L. Cesar, P. D. Bowe, Niels Madsen, V. Lagomarsino, V. Filippini, Paolo Montagna, P. Genova, C. Carraro, C. Regenfus, M. C. Fujiwara, Alberto Rotondi, R. Funakoshi, Adriano Fontana, Claude Amsler, Ryugo S. Hayano, D. Lindelöf, H. Pruys, L. V. Jørgensen, Germano Bonomi, E. Lodi Rizzini, G. Testera, and Michael Doser

Subjects
Physics, Nuclear and High Energy Physics, Antihydrogen, Modes, Plasma, Plasma parameters, Penning trap, Sweep frequency response analysis, Nuclear physics, Positron, Physics::Plasma Physics, Antiproton, Antimatter, Physics::Atomic Physics, Atomic physics, Instrumentation
Abstract

In the ATHENA experiment, which has recently produced and detected cold antihydrogen, the antiatoms formation is performed by mixing two cold (meV) charged clouds of positrons and antiprotons. The antihydrogen production is strictly dependent on positron plasma parameters. For this purpose we developed a new system to investigate such properties in a non-destructive way. The method is based upon the measurement of the plasma response under a frequency sweep RF excitation and its subsequent analysis. Plasmas trapped in Penning trap exhibit typical resonant collective modes characterized by frequencies, amplitudes and widths dependent on the particle number, density, spatial extent and temperature. With this system it is so possible to have a real-time monitor of the plasma during antihydrogen production.

Published
2004

129. Temperature dependence of anti-hydrogen production in the ATHENA experiment

Author

C. Carraro, M. Macri, Niels Madsen, M. C. Fujiwara, V. Lagomarsino, V. Filippini, R. Funakoshi, R. Landua, C. Regenfus, Claude Amsler, Adam Bouchta, M. Charlton, Germano Bonomi, G. Testera, H. Pruys, Alberto Rotondi, P. Montagna, Alessandro Variola, J. S. Hangst, Adriano Fontana, L. V. Jørgensen, C. L. Cesar, Ryugo S. Hayano, Petra Riedler, D. P. van der Werf, D. Lindelöf, Michael Doser, P. Genova, M. Amoretti, E. Lodi Rizzini, and P. D. Bowe

Subjects
Condensed Matter::Quantum Gases, Nuclear and High Energy Physics, Positron, Chemistry, Dielectric heating, Mixing (process engineering), Physics::Accelerator Physics, Physics::Atomic Physics, Plasma, Atomic physics, Instrumentation, Hydrogen production, Production rate
Abstract

The ATHENA experiment recently produced the first sample of cold anti-hydrogen atoms by mixing cold plasmas of anti-protons and positrons. The temperature of the positron plasma was increased by controlled RF heating and the anti-hydrogen production rate was measured. Preliminary results are presented.

Published
2004

130. Anti-pp annihilation into four charged pions at rest and in flight

Author

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

Subjects
Physics, Particle physics, Large Hadron Collider, Annihilation, Physics and Astronomy (miscellaneous), Spectrometer, Hydrogen, Gaseous hydrogen, chemistry.chemical_element, Nuclear physics, Pion, chemistry, High Energy Physics::Experiment, Exotic meson, Engineering (miscellaneous)
Abstract

The spin-parity analysis of the data on the ¯pp → 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

131. High rate production of antihydrogen

Author

C. Carraro, P. Genova, V. Filippini, M. C. Fujiwara, R. Funakoshi, C. L. Cesar, E. Lodi Rizzini, H. Pruys, M. Marchesotti, D. P. van der Werf, L. V. Jørgensen, G. Testera, Germano Bonomi, Ryugo S. Hayano, D. Lindelöf, Niels Madsen, M. Amoretti, Michael Doser, C. Regenfus, R. Landua, Alberto Rotondi, P. D. Bowe, G. Manuzio, P. Montagna, V. Lagomarsino, Claude Amsler, Adriano Fontana, G. Bazzano, Alessandro Variola, J. S. Hangst, Petra Riedler, M. Charlton, Adam Bouchta, M. Macri, and G. Rouleau

Subjects
Nuclear physics, Physics, High rate, Physics::General Physics, Nuclear and High Energy Physics, Antiparticle, Positron, Antiproton, High Energy Physics::Experiment, Physics::Atomic Physics, Atomic physics, Antihydrogen, Production rate
Abstract

We show that antihydrogen production is the dominant process when mixing antiprotons and positrons in the ATHENA apparatus, and that the initial production rate exceeds 300 Hz, decaying to 30 Hz within 10 s. A fraction of 65% of all observed annihilations is due to antihydrogen.

Published
2004

132. The ATHENA antihydrogen apparatus

Author

Germano Bonomi, W. Joffrain, P. Genova, M. Marchesotti, D. P. van der Werf, G. Rouleau, Adriano Fontana, Niels Madsen, R. Landua, M. Macri, M. Charlton, Alessandro Variola, T. Yamazaki, J. S. Hangst, P. D. Bowe, E. Lodi-Rizzini, M. H. Holzscheiter, Hiroyuki Higaki, M. J. T. Collier, Adrian Glauser, D. Manuzio, C. Lenz Cesar, G. Testera, M. Amoretti, C. Carraro, Claude Amsler, Michael Doser, V. Filippini, M. C. Fujiwara, P. Montagna, R. Funakoshi, C. Regenfus, K.S. Fine, Ryugo S. Hayano, D. Lindelöf, H. Pruys, L. V. Jørgensen, V. Lagomarsino, J. Rochet, G. Manuzio, T. L. Watson, Petra Riedler, Alberto Rotondi, Yasunori Yamazaki, D. Grögler, and Adam Bouchta

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Detector, High resolution, Penning trap, Magnetic field, Nuclear physics, Positron, Antiproton, Physics::Accelerator Physics, High Energy Physics::Experiment, Physics::Atomic Physics, Antihydrogen, Instrumentation, Particle Physics - Experiment
Abstract

The ATHENA apparatus that recently produced and detected the first cold antihydrogen atoms is described. Its main features, which are described herein, are: an external positron accumulator, making it possible to accumulate large numbers of positrons; a separate antiproton catching trap, optimizing the catching, cooling and handling of antiprotons; a unique high resolution antihydrogen annihilation detector, allowing an clear determination that antihydrogen has been produced; an open, modular design making variations in the experimental approach possible and a “nested” Penning trap situated in a cryogenic, 3T magnetic field environment used for the mixing of the antiprotons and positrons.

Published
2004

133. Antihydrogen Formation using Cold Plasmas

Author

Niels Madsen, C. L. Cesar, D. Mitchard, M. Amoretti, C. Carraro, M. C. Fujiwara, R. Funakoshi, Alban Kellerbauer, R. Landua, Ryugo S. Hayano, M. Charlton, Paolo Montagna, H.S. Pruys, Andrea Fontana, Adam Bouchta, Germano Bonomi, I. Johnson, Claude Amsler, Alessandro Variola, J. S. Hangst, M. Macri, D. P. van der Werf, G. Testera, P. Genova, Michael Doser, Alberto Rotondi, L. V. Jørgensen, G. Manuzio, P. D. Bowe, C. Regenfus, V. Lagomarsino, E. Lodi-Rizzini, Cohen, J.S., Mazevet, S., and Kilcrease, D.P.

Subjects
Condensed Matter::Quantum Gases, Physics, Physics::General Physics, Annihilation, Hydrogen, chemistry.chemical_element, Hydrogen atom, Plasma, Nuclear physics, Positron, chemistry, Antiproton, Antimatter, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, Atomic physics, Antihydrogen
Abstract

Antihydrogen, the antimatter counterpart of the hydrogen atom, can be formed by mixing cold samples of antiprotons and positrons. In 2002 the ATHENA collaboration succeeded in the first production of cold antihydrogen. By observing and imaging the annihilation products of the neutral, non‐confined, antihydrogen atoms annihilating on the walls of the trap we can observe the production in quasi‐real‐time and study the dynamics of the formation mechanism. The formation mechanism strongly influences the final state of the formed antihydrogen atoms, important for future spectroscopic comparison with hydrogen. This paper briefly summarizes the current understanding of the antihydrogen formation in ATHENA.

Published
2004

134. Hypernuclei production with stopped K- at DAΦNE

Author

Elena Botta, A. Lanaro, N. Grion, Rinaldo Rui, S. Marcello, F. D'Isep, Michelangelo Agnello, Bruno Minetti, V. Paticchio, Antonietta Donzella, S. Tessaro, A. Filippi, D. Calvo, E. Lodi Rizzini, E. Rossetto, Felice Iazzi, A. Sharma, Tullio Bressani, P. Gianotti, S. Costa, V. Lucherini, L. Venturelli, A. Zenoni, C. Guaraldo, Paolo Camerini, G. Bonazzola, A. Feliciello, M., Agnello, G. C., Bonazzola, E., Botta, T., Bressani, D., Calvo, Camerini, Paolo, S., Costa, F., D'Isep, A., Donzella, A., Feliciello, A., Filippi, P., Gianotti, N., Grion, C., Guaraldo, F., Iazzi, A., Lanaro, E., Lodi Rizzini, V., Lucherini, S., Marcello, B., Minetti, V., Paticchio, E., Rossetto, Rui, Rinaldo, A., Sharma, S., Tessaro, L., Venturelli, and A., Zenoni

Subjects
hypernuclei, Nuclear physics, Physics, hypernuclear physics, kaons, Nuclear and High Energy Physics, Field (physics), Spectrometer, hypernuclear physic, High Energy Physics::Experiment, Nuclear Experiment
Abstract

The low-energy, background free and tagged K-following the o(1020) decay produced at the DAΦNE o-factory in Frascati represent a unique opportunity to carry out a dedicated program of hypernuclear physics with K − at rest. In this paper we give a survey of this challenging field and we describe the performances of a magnetic spectrometer designed for precise measurements of hypernuclei energy levels and of their decays modes.

Published
1993

135. Antinucleon-nucleon annihilation cross section measurements at low energies

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Annihilation, Spectrometer, anti nucleon annihilation, Oelix, P wave, Nuclear physics, Cross section (physics), Low energy, Atomic physics, Nucleon
Abstract

First results concerning p -p and n -p annihilation cross section and n -p total cross sections at low energies ( 2.25 ≤ E P ≤ 22.76 MeV and 3.4 E n MeV ) obtained by the OBELIX spectrometer are reported. The agreement with the few existing data in this energy range is good; the comparison with some models gives interesting indications on the S and P wave contribution at very low energy and on the range of the elastic interaction.

Published
1993

136. A new measurement of the Pontecorvo reaction with the OBELIX spectrometer at LEAR

Author

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

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Meson, Spectrometer, Field (physics), Branching fraction, DEUTERIUM, Degrees of freedom (physics and chemistry), Nuclear physics, Reaction rate, ANTIPROTON ANNIHILATION, Pi
Abstract

Antinucleon-nucleus annihilations into two-body final states containing only one or no meson are unusual annihilations (Pontecorvo reactions), practically unexplored experimentally, with the exception of the channel p d → π − p , for which only two low-statistics measurements exist. Their physical interest lies in the possibility of exploring small-distance nuclear dynamics, in which an important role can be played by non-nucleonic degrees of freedom. A new measurement of the p d → π − p reaction rate at rest, performed with the OBELIX spectrometer at LEAR, with the best statistics up to now and a careful evaluation of systematic effects is reported, together with a critical analysis of the existing theoretical models. The measured branching ratio, which confirms the previous results, can represent a reference point for the studies in the field.

Published
1993

137. New results on meson spectroscopy from Obelix

Author

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

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Particle decay, Annihilation, Pion, Meson, Hadron, Dalitz plot, Quarkonium, Spin (physics), Meson spectroscopy
Abstract

A preliminary final state analysis of a sample of n p in-flight annihilations into three and five charged pions is presented. The partial-wave analysis of three-prong data confirms previous interpretations of the Ax ƒ 2 (1520) resonance, from p p annihilations at rest. Concerning five-prong events our analysis favours spin 0 for the already reported ζ (1480) state, but more refined calculations are underway. At high n momenta, the five-prong data show some evidence for a possible spin 2 state at 1640 MeV/c 2 decaying in ρ ° ρ °.

Published
1993

138. Anti-p stopping power in hydrogen below 1 MeV and the anti-p 4He metastable state

Author

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. Cicaló, M. Corradini, S. Costa, S. De Castro, F. D'Isep, A. Donzella, 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, G. Maron, A. Masoni, I. Massa, B. Minetti, M. Morando, P. Montagna, F. Nichitiu, M. Panzieri, G. Pauli, M. Piccinini, G. Piragino, M. Poli, G. Puddu, R. A. Ricci, C. Rizzo, E. Rossetto, A. Rotondi, A. M. Rozhdestvensky, P. Salvini, L. Santi, M. G. Sapozhmkov, N. Semprini Cesari, S. Serci, P. Temnikov, F. Tosello, V. I. Tretyak, G. L. Usai, L. Vannucci, S. Vecchi, G. Vedovato, L. Venturelli, M. Villa, A. Vitale, E. Zavattini, A. Zenom, A. Zoccoli, G. Zosi, MARGAGLIOTTI, GIACOMO, TESSARO, SUSANNA, 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., Cicaló, M., Corradini, S., Costa, S., De Castro, F., D'Isep, A., Donzella, 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, M., Panzieri, G., Pauli, M., Piccinini, G., Piragino, M., Poli, G., Puddu, R. A., Ricci, C., Rizzo, E., Rossetto, A., Rotondi, A. M., Rozhdestvensky, P., Salvini, L., Santi, M. G., Sapozhmkov, N., Semprini Cesari, S., Serci, P., Temnikov, Tessaro, Susanna, F., Tosello, V. I., Tretyak, G. L., Usai, L., Vannucci, S., Vecchi, G., Vedovato, L., Venturelli, M., Villa, A., Vitale, E., Zavattini, A., Zenom, A., Zoccoli, and G., Zosi

Subjects
Helium, rates, Stopping power, rate
Abstract

The stopping power of H-2 for psBAR was measured in the pBAR energy interval 1 keV divided-by 120 keV using a low density gas target (rho/rho(o) = 10(-3) divided-by 10(-2), rho(o) being the H2 density at STP) with the OBELIX spectrometer at the LEAR of CERN. Furthermore, the formation of metastable states in the pBAR He-4 interaction at rest, having a mean life of the order of 3 mus, was investigated at six target gas pressures (3 atm and 400, 250, 200, 150, 50 mbar). The influence of contaminants (like H-2, Ne, Ar, N2 and Xe) on the life of such metastable states was examined at the target gas pressure of 3 atm.

Published
1993

139. Cold antihydrogen at ATHENA: Experimental observation and beyond

Author

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

Subjects
Nuclear physics, Physics, education.field_of_study, Positron, Large Hadron Collider, Antiproton, Population, Parity (physics), Physics::Atomic Physics, Cooling efficiency, education, Antihydrogen, Quantum number
Abstract

Antihydrogen atoms may become the easiest and most precise way to probe deeply into tests of violation of the CPT (charge conjugation, parity, time reversal) symmetry and the Weak Equivalence Principle (WEP). We review the first production of cold antihydrogen atoms within the ATHENA/AD‐1 experiment at CERN, its motivations and studies henceforth. The ATHENA success was followed almost immediately by the ATRAP group. From the initial claim of production of tens of thousand of these exotic species — by the mixing of cold and trapped positrons and antiprotons — we have evolved to better understand and control the system. The joint production for 2002 and 2003 has been re‐evaluated to about one million antiatoms. We have performed cooling efficiency studies of antiprotons within the positron cloud; developed ways to excite and heat the positron cloud, and probe its number, density and temperature in situ; developed antiproton and antihydrogen imaging tomography. We have also been able to gather information on the velocity of the formed antiatoms. A large uncertainty and lack of control remains over the formation process — as revealed by its measured temperature dependence — and the quantum number distribution of the population. We discuss various aspects of our findings below as well as future prospects for physics tests with antihydrogen.

Published
2003

140. Transfer, stacking and compression of positron plasmas under UHV conditions

Author

L. V. Jo, Alessandro Variola, J. S. Hangst, rgensen, Ryugo S. Hayano, C. Carraro, V. Filippini, Paolo Montagna, C. Regenfus, E. Lodi Rizzini, M. C. Fujiwara, R. Landua, Alberto Rotondi, P. D. Bowe, P. Genova, R. Funakoshi, G. Testera, M. Macri, V. Lagomarsino, M. Amoretti, Michael Doser, M. Charlton, H.S. Pruys, Andrea Fontana, C. L. Cesar, Adam Bouchta, Germano Bonomi, Niels Madsen, D. P. van der Werf, and G. Manuzio

Subjects
Physics, Positron, Physics::Plasma Physics, Electric field, Stacking, Magnetic pressure, Plasma, Atomic physics, Compression (physics), Rotation, Magnetic field
Abstract

A ballistic method is presented for transferring positron plasmas emanating from a region with a low magnetic field and relatively high pressure into a 15 K Penning‐Malmberg trap immersed in a 3 T magnetic field with a base pressure of the order of 10−13 mbar. Subsequent stacking resulted in a plasma containing 4.2 × 108 positrons. Using a rotating wall electric field a plasma containing 90 million positrons was compressed to a density of 3.6 × 109 cm−3.

Published
2003

141. Non-Destructive Positron Plasma Diagnostics for Antihydrogen Production

Author

rgensen, Alessandro Variola, J. S. Hangst, R. Landua, E. Lodi Rizzini, M. Macri, Claude Amsler, Andrea Fontana, C. Regenfus, Paolo Montagna, C. Carraro, V. Filippini, M. C. Fujiwara, Adam Bouchta, G. Testera, P. Genova, P. D. Bowe, R. Funakoshi, D. P. van der Werf, Michael Doser, C. L. Cesar, Niels Madsen, Ross L. Spencer, M. Amoretti, V. Lagomarsino, Alberto Rotondi, H.S. Pruys, Germano Bonomi, G. Manuzio, M. Charlton, Ryugo S. Hayano, D. Lindelöf, and L. V. Jo

Subjects
Physics, Plasma, Plasma oscillation, Dipole, Positron, Physics::Plasma Physics, Antimatter, Physics::Space Physics, Quadrupole, Physics::Accelerator Physics, Plasma diagnostics, Physics::Atomic Physics, Atomic physics, Antihydrogen
Abstract

Production of antihydrogen atoms by mixing antiprotons with a cold, confined, positron plasma depends on parameters such as the plasma density and temperature. We discuss a non‐destructive diagnostic, based on an analysis of excited, low‐order plasma modes, that provides comprehensive characterization of the positron plasma in the ATHENA antihydrogen apparatus. The dipole and quadrupole modes of a spheroidal positron plasma are interpreted in the framework of a cold fluid theory. In particular, the excitation and detection of the dipole mode are analytically modeled considering the response of the center‐of‐mass to a resonant driving perturbation. The model is compared to, and validated by, numerical simulations with a particle‐in‐cell code. Measurements of the positron plasma properties are discussed.

Published
2003

142. Results of the coupled channel analysis of pi+ pi- pi0, K+ K- pi0 and K+- K0(S) pi-+ final states from anti-p p annihilation at rest in hydrogen targets at different densities

Author

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

Subjects
Physics, Nuclear and High Energy Physics, COLLISIONS, Annihilation, PI(0)ETA-ETA, Hydrogen, Scattering, Glueball, PI(0)PI(0)PI(0), F(0)(1500), chemistry.chemical_element, GLUEBALL, ANTIPROTON-PROTON ANNIHILATION, H-2 GAS, chemistry, MULTI-QUARK HADRONS, S-STATE, SEARCH, High mass, Channel analysis, Atomic physics
Abstract

The π+π−π0, K+K−π0 and K±K0π∓ final states produced by p p annihilation at rest at three different hydrogen target densities have been analyzed in the frame of a coupled channel analysis together with ππ and πK scattering data. Here we present the main results which concern masses, widths, ππ and K K partial widths of all the involved resonances (JP=0+,1−,2+), the direct determination of Γ K K /Γ ππ ratio for f0(1370) and f0(1500) ( Γ K K /Γ ππ =0.91±0.20 and Γ K K /Γ ππ =0.25±0.03 , respectively), the determination of a0(1300) parameters (M=1303±16 MeV; Γ=92±16 MeV) and the observation of two different high mass ρ signals associated to ρ(1450) and ρ(1700) (M=1182±30 MeV; Γ=389±20 MeV and M=1594±20 MeV; Γ=259±20 MeV, respectively).

Published
2003

143. Complete nondestructive diagnostic of nonneutral plasmas based on the detection of electrostatic modes

Author

G. Testera, Ryugo S. Hayano, M. Macri, Germano Bonomi, Michael Doser, Alessandro Variola, J. S. Hangst, C. L. Cesar, D. P. van der Werf, R. Landua, P. D. Bowe, E. Lodi Rizzini, G. Manuzio, V. Lagomarsino, P. Genova, Niels Madsen, Adam Bouchta, C. Carraro, M. C. Fujiwara, L. V. Jørgensen, M. Charlton, Adriano Fontana, R. Funakoshi, and M. Amoretti

Subjects
Physics, Antimatter, Plasma diagnostics, Plasma, Atomic physics, Condensed Matter Physics, Line (formation)
Abstract

The detection of electrostatic nonneutral plasma modes in the ATHENA (ApparaTus for High precision Experiment on Neutral Antimatter) experiment [M. Amoretti, C. Amsler, G. Bonomi et al., Nature (London) 419, 456 (2002)] is described. A complete nondestructive diagnostic of the plasma based on a fit to the line shape of the function describing the power transmitted through the plasma around the frequency of the fundamental mode is developed and the experimental results are presented and discussed.

Published
2003

144. Protonium annihilation in P-wave using low-density (ϱ/ϱ∼10−3) hydrogen targets. Measurements of cascade times and widths

Author

G. L. Usai, I. Massa, S. Marcello, N. Semprini Cesari, L. Santi, F. D'Isep, I.V. Falomkin, Bruno Minetti, A. Zenomi, Paolo Montagna, A. Maggiora, C. Guaraldo, G. Bonazzola, Felice Iazzi, Antonio Zoccoli, A. Grasso, V. Lucherini, Michelangelo Agnello, M. Morando, P.P. Temnikov, L. Fava, M. Lombardi, A.M. Rozhdestvensky, G. Piragino, Gianfranco Zosi, S. De Castro, Corrado Cicalo, M. Corradini, P. Gianotti, A. Adamo, G. Pauli, M.G. Sapozhnikov, S. Serci, G. V. Margagliotti, Marco Bruschi, F. Nichitiu, L. Busso, Alberto Masoni, L. Venturelli, D. Galli, G. Bendiscioli, Armando Lanaro, V.I. Tretyak, R. A. Ricci, M.P. Bussa, D. Panzieri, E. Lodi Rizzini, M. Capponi, Tullio Bressani, G. Maron, S. Costa, G. Puddu, M. Piccinini, U. Gastaldi, F. Tosello, M. Poli, G. Vedovato, S. Tessaro, E. Rossetto, G.B. Pontecorvo, I. D'Antone, D. Calvo, Mauro Villa, L. Ferrero, A. Bertin, R. Garfagnini, Alberto Rotondi, A. Feliciello, P. Boccaccio, U. Marconi, V. Filippini, A. Vitale, G. Zavattini, F. Balestra, Paola Salvini, L. Vannucci, G. Belli, 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., Cicaló, M., Corradini, S., Costa, I., D'Antone, S., De Castro, F., D'Isep, I. V., Falomkin, 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. B., Pontecorvo, 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, S., Tessaro, F., Tosello, V. I., Tretyak, G. L., Usai, L., Vannucci, G., Vedovato, L., Venturelli, M., Villa, A., Vitale, G., Zavattini, A., Zenomi, A., Zoccoli, and G., Zosi

Subjects
Physics, Nuclear and High Energy Physics, Angular momentum, Annihilation, Hydrogen, P wave, chemistry.chemical_element, ANTIPROTONIC-HYDROGEN, chemistry, Cascade, Protonium, Atom, PBARP ANNIHILATION, Low density, Atomic physics
Abstract

The use of low-density hydrogen targets is demonstrated experimentally to be a new way of selecting protonium ( p p atom) annihilations with initial angular momentum L = 1. The mean value and the width of the time distributions which occur between protonium formation and annihilation have been measured at room temperature at 8.2, 4.1, 2.1 mbar. They are (110±10; 45±5), (145±15; 82±9) and (210±25;125±9) ns, respectively.

Published
1992

145. Meson spectroscopy with antineutrons

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Hydrogen, Meson, ANNIHILATIONS, chemistry.chemical_element, Elementary particle, Antineutron, meson spectroscopy, antineutron proton annhilation, Nuclear physics, Momentum, chemistry, Invariant mass, Atomic physics, Spectroscopy
Abstract

First results on meson spectroscopy using antineutrons as projectiles are reported. Three-body (π + π + π − ) and five-body (π + π + π + π − π − ) final states following the annihilation of 100 to 290 MeV/ c antineutrons on hydrogen were analyzed. The (π + π − ) invariant mass spectrum in the three-body reaction is accounted for by the ϱ 0 anf f 2 (1270) resonances, together with an enhancement around 1540 MeV, in the region of the AX (1565) and the f 2 (1515) resonances, whereas the best fit for the (π + π + π − π − ) invariant mass in five-body events shows the already reported structure ζ(1480) and suggests the presence of a second structure around 1650 MeV.

Published
1992

146. The antineutron beam at LEAR

Author

Paola Gianotti, S. Serci, G. Puddu, Bruno Minetti, S. Tessaro, G. Pauli, S. Costa, L. Venturelli, E. Lodi Rizzini, Alberto Masoni, Felice Iazzi, D. Calvo, S. Marcello, Tullio Bressani, F. D'Isep, Michelangelo Agnello, G. V. Margagliotti, and Alessandro Feliciello

Subjects
Nuclear physics, Physics, Neutron source, Antineutron, Beam (structure)
Published
2002

147. Study of the K^+ K^- π^+ π^- π^0 final state in antiproton annihilation at rest in gaseous hydrogen at NTP with the OBELIX spectrometer

Author

Nichitiu, F., P. Gianotti, C. Guaraldo, A. Lanaro, V. Lucherini, C. Petrascu, A. Rosca, G. Bonomi, M. P. Bussa, A. Donzella, E. Lodi Rizzini, L. Venturelli, A. Zenoni, A. Bertin, M. Bruschi, M. Capponi, S. De Castro, D. Galli, B. Giacobbe, U. Marconi, I. Massa, M. Piccinini, N. Semprini-Cesari, R. Spighi, S. Vecchi, V. Vagnoni, M. Villa, A. Vitale, A. Zoccoli, C. Cical`O, A. De Falco, A. Masoni, S. Mauro, G. Puddu, G. Usai, O. E. Gorchakov, S. N. Prakhov, A. M. Rozhdestvensky, V. I. Tretyak, M. Poli, V. Filippini, A. Fontana, P. Montagna, A. Rotondi, P. Salvini, F. Balestra, L. Busso, P. Cerello, O. Denisov, R. Garfagnini, A. Grasso, A. Maggiora, A. Panzarasa, D. Panzieri, F. Tosello, E. Botta, T. Bressani, D. Calvo, S. Costa, D. D'Isep, A. Feliciello, A. Filippi, S. Marcello, M. Agnello, F. Iazzi, B. Minetti, N. Mirfakhrai, and S. Tessaro

Abstract

A spin-parity analysis of a sample of p ̅p→ K^+ K^- π^+ π^- π^0 annihilation events taken at rest in gaseous H_{2} at NTP is reported. The invariant mass spectrum of the K^+ K^- π^0 system shows the presence of the E/iota resonance pattern at 1.42 GeV. The analysis of this signal confirms the results obtained by the OBELIX Collaboration in previous works, namely: the existence of two pseudoscalar states at 1.413±0.002 and 1.460 ± 0.012 GeV with widths 0.051 ±0.004 and 0.120 ± 0.015 GeV, respectively. The p ̅p system in the ^{3}P_{1} wave shows also a signal corresponding to the axial vector f_{1}(1420) decaying to K^{*}{K} with mass 1.420 ± 0.003 GeV and width 0.061±0.005 GeV. A study of the incoherent phase space background shows that its origin is mostly due to the reflection of a resonant state in the K^+ K^- π^+ π^- system. The isobar decomposition of this resonant state is mainly f_{0}(1370)(ππ)_{S}, its parameters are: J^{PC} = 0^{++}, m = 1.670 ± 0.02 GeV and width 0.267±0.036 GeV. This signal can be probably identified with another decay mode of the f_{0}(1710).

Published
2002
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148. Production and detection of cold antihydrogen atoms

Author

P. Montagna, Alessandro Variola, J. S. Hangst, Niels Madsen, M. Amoretti, M. Charlton, E. Lodi Rizzini, Ryugo S. Hayano, G. Testera, Germano Bonomi, D. Lindelöf, M. Marchesotti, M. H. Holzscheiter, C. Carraro, T. L. Watson, M. C. Fujiwara, Claude Amsler, K.S. Fine, Michael Doser, Alberto Rotondi, H. Pruys, R. Funakoshi, L. V. Jørgensen, V. Lagomarsino, J. Rochet, R. Landua, Petra Riedler, C. L. Cesar, D. P. van der Werf, Adriano Fontana, M. J. T. Collier, V. Filippini, G. Manuzio, P. D. Bowe, P. Genova, M. Macri, G. Rouleau, A. Bouchta, and C. Regenfus

Subjects
Physics, Physics::General Physics, Antiparticle, Multidisciplinary, CPT symmetry, Elementary particle, Particle detector, Antiproton Decelerator, Nuclear physics, Antiproton, Antimatter, High Energy Physics::Experiment, Physics::Atomic Physics, Antihydrogen
Abstract

A theoretical underpinning of the standard model of fundamental particles and interactions is CPT invariance, which requires that the laws of physics be invariant under the combined discrete operations of charge conjugation, parity and time reversal. Antimatter, the existence of which was predicted by Dirac, can be used to test the CPT theorem—experimental investigations involving comparisons of particles with antiparticles are numerous1. Cold atoms and anti-atoms, such as hydrogen and antihydrogen, could form the basis of a new precise test, as CPT invariance implies that they must have the same spectrum. Observations of antihydrogen in small quantities and at high energies have been reported at the European Organization for Nuclear Research (CERN)2 and at Fermilab3, but these experiments were not suited to precision comparison measurements. Here we demonstrate the production of antihydrogen atoms at very low energy by mixing trapped antiprotons and positrons in a cryogenic environment. The neutral anti-atoms have been detected directly when they escape the trap and annihilate, producing a characteristic signature in an imaging particle detector.

Published
2002

149. Study of the K+.K-.pi+.pi-.pi0 final state in antiproton annihilation at rest in gaseous hydrogen at NTP with the OBELIX spectrometer

Author

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

Subjects
Pseudoscalar, Physics, Nuclear and High Energy Physics, Annihilation, Antiproton, Isobar, Resonance, Invariant mass, Atomic physics, Pseudovector, P system
Abstract

A spin-parity analysis of a sample of p p→K + K − π + π − π 0 annihilation events taken at rest in gaseous H2 at NTP is reported. The invariant mass spectrum of the K+K−π0 system shows the presence of the E/ι resonance pattern at 1.42 GeV. The analysis of this signal confirms the results obtained by the OBELIX Collaboration in previous works, namely: the existence of two pseudoscalar states at 1.413 ± 0.002 and 1.460±0.012 GeV with widths 0.051 ± 0.004 and 0.120±0.015 GeV, respectively. The p p system in the 3 P 1 wave shows also a signal corresponding to the axial vector f1(1420) decaying to K ∗ K with mass 1.420±0.003 GeV and width 0.061±0.005 GeV. A study of the incoherent phase space background shows that its origin is mostly due to the reflection of a resonant state in the K+K−π+π− system. The isobar decomposition of this resonant state is mainly f0(1370)(ππ)S, its parameters are: JPC=0++, m=1.670±0.02 GeV and width 0.267±0.036 GeV. This signal can be probably identified with another decay mode of the f0(1710).

Published
2002

150. The antineutron beam at LEARConference Record of the 1991 IEEE Nuclear Science Symposium and Medical Imaging Conference

Author

M. Agnello, T. Bressani, F. D'Isep, D. Calvo, S. Costa, A. Feliciello, P. Gianotti, F. Iazzi, S. Marcello, B. Minetti, E. Lodi Rizzini, L. Venturelli, G. Pauli, S. Tessaro, A. Masoni, S. Serci, G. Puddu, MARGAGLIOTTI, GIACOMO, A.A.V.V., M., Agnello, T., Bressani, F., D'Isep, D., Calvo, S., Costa, A., Feliciello, P., Gianotti, F., Iazzi, S., Marcello, B., Minetti, E., Lodi Rizzini, L., Venturelli, Margagliotti, Giacomo, G., Pauli, S., Tessaro, A., Masoni, S., Serci, and G., Puddu

Subjects
Antineutron beams
Published
1991

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