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18 results on '"T. Bressani"'

1. New data on Δ++-baryon production in annihilation at rest

Author

A. Bertin, M. Bruschi, M. Capponi, A. Collamati, S. De Castro, R. Donà, A. Ferretti, D. Galli, B. Giacobbe, U. Marconi, M. Piccinini, M. Poli, N. Semprini Cesari, R. Spighi, S. Vecchi, A. Vezzani, F. Vigotti, M. Villa, A. Vitale, A. Zoccoli, M. Corradini, A. Donzella, E. Lodi Rizzini, L. Venturelli, A. Zenoni, C. Cicalò, A. Masoni, G. Puddu, S. Serci, P. Temnikov, G. Usai, O. Gortchakov, S. Prakhov, A. Rozhdestvensky, M. Sapozhnikov, V. Tretyak, P. Gianotti, C. Guaraldo, A. Lanaro, V. Lucherini, F. Nichitiu, C. Petrascu, A. Rosca, V. Ableev, C. Cavion, U. Gastaldi, M. Lombardi, G. Maron, L. Vannucci, G. Vedovato, G. Bendiscioli, V. Filippini, A. Fontana, P. Montagna, A. Rotondi, A. Saino, P. Salvini, C. Scoglio, F. Balestra, E. Botta, T. Bressani, M.P. Bussa, L. Busso, D. Calvo, P. Cerello, S. Costa, O. Denisov, L. Fava, A. Feliciello, L. Ferrero, A. Filippi, R. Garfagnini, A. Grasso, A. Maggiora, S. Marcello, D. Panzieri, D. Parena, E. Rossetto, F. Tosello, L. Valacca, G. Zosi, M. Agnello, F. Iazzi, B. Minetti, G. Pauli, S. Tessaro, and L. Santi

Subjects
Physics, Baryon, Nuclear physics, Nuclear and High Energy Physics, Annihilation, Pion, Proton, Deuterium, Analytical chemistry, Invariant mass, Production (computer science)
Abstract

New experimental results on p d annihilation at rest into pions plus a high momentum proton in the final state are discussed. The data sample was collected using the OBELIX spectrometer at the LEAR facility (CERN). The annihilation probabilities, or more precisely the yields (Y) via channels p d → 2π − π + π 0 p and p d → 3π − 2π + π 0 p with proton momenta p > 400 MeV/c have been measured for the first time: Y = (93.2 ± 1.6) × 10−4 and Y = (52.2 ± 1.4) × 10−4, respectively. The signal in the invariant mass distribution of the pπ+ system in the region of the well-known Δ++(1232)-isobar is clearly seen in reactions p d → 2π − π + p , p d → 2π − π + π 0 p , p d → 3π − 2π + p and p d → 3π − 2π + π 0 p . The upper limit on reaction p (Δ − Δ ++ ) → 2π − π + p in the p d annihilation at rest, which could be interpreted as a manifestation of the ΔΔ component of the deuteron, was found to be Y ≤ 6.5 × 10−5 with a 90% confidence level.

Published
1997

2. P̄P partial cross sections at low energy

Author

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

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Pair production, Annihilation, Meson, Scattering, Protonium, Branching fraction, Hadron, Scattering length, Atomic physics, Atomic and Molecular Physics, and Optics
Abstract

New measurements of the pp total annihilation cross-section at very low momenta (around 50 MeV/c) confirm the previous results obtained by the OBELIX collaboration. The measured values are in general agreement with a scattering length approximation of the annihilation cross-section where the pp scattering lengths are obtained from measurement of the protonium shifts and widths and which accounts for the Coulomb interaction. Partial annihilation cross-sections and annihilation frequencies for some channels have been measured too. The values of the total and partial cross sections at the lowest p momentum show an unexpected behaviour

Published
1997

3. 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

4. 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

5. Measurement of the Pbarp Annihilation Cross-sections At Very Low Energies

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Meson, Spectrometer, cross sections, Scattering length, SCATTERING, PBARP ANNIHILATION, Nuclear physics, antiproton proton annihilation, OBELIX, PS201, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Order of magnitude
Abstract

The p p annihilation cross-sections at 66.4–68.9–71.4 MeV/c have been measured using the presently instrumented part of the OBELIX spectrometer. The results have been obtained at p energies ( ≃ 2.5 MeV) by one order of magnitude smaller than in any existing experiment concerning the in-flight antiproton-proton annihilation. The average value obtained over the total interval 65.1–72.5 MeV/c, βσanT = 33.2 ± 1.7 (stat.) ±1.8 (syst.) mb, in agreement with a specific calculation, would favour for the spin-averaged S-wave scattering length the value (−0.7 + i0.8) fm. The branching ratios for the annihilations in two, four and six charged mesons turn out to be quite similar to those for annihilation at rest in liquid hydrogen.

Published
1991

6. Measurement of the Annihilation Cross-Section for Antineutrons on Fe from 100 to 531 MeV/c

Author

Cagliari-Padova-Torino Collaboration, M Agnello, F Iazzi, B Minetti, L Cugusi, M. P Macciotta, S Marcello, A Masoni, G Puddu, A Raimondi, S Serci, M. T Sergi, T Bressani, S Costa, G Dellacasa, A Feliciello, M Gallio, A Musso, M Morandin, C Voci, and R. A Ricci

Subjects
Physics, Nuclear physics, SIMPLE (dark matter experiment), Scaling law, Cross section (physics), Annihilation, Detector, General Physics and Astronomy, Atomic physics, Absorption (electromagnetic radiation)
Abstract

The cross-section for annihilation on Fe from 100 to 531 MeV/c was measured by means of a layered absorption detector. The cross-sections are related to the free N annihilation cross-sections by a simple A2/3 scaling law, indicating a surface process.

Published
1988

7. φ and ω meson production in annihilation and the OZI rule

Author

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

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, 4-QUARK EXOTICS, Elementary particle, Antineutron, Omega, Nuclear physics, OZI rule, Mass spectrum
Abstract

The φπ + /ωπ + ratio from n ¯ p annihilations on a liquid hydrogen target, for n ¯ momenta between 64 and 297 MeV/ c , was measured using the OBELIX spectrometer at LEAR. The ratio R ( ϕ π / ω π ) = σ ( n ¯ p → ϕ π + ) / σ ( n ¯ p → ω π + ) turned out 0.110±0.015 stat ±0.006 syst . Implications of this result on the OZI rule are discussed.

Published
1994

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

Author

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

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

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

Published
1993

9. Dynamical selection rules from p anti-p annihilation at rest in three meson final states

Author

G. Puddu, Paolo Montagna, R. Garfagnini, P. Cerello, Antonio Zoccoli, V. Filippini, M. Corradini, A. Bertin, F. Nichitiu, L. Venturelli, C. Guaraldo, E. Lodi Rizzini, Michelangelo Agnello, Armando Lanaro, Elena Botta, G. Pauli, Felice Iazzi, C. Cavion, S.N. Prakhov, Aldo Zenoni, M. Astrua, A. Saino, G. L. Usai, L. Ferrero, Andrea Fontana, G. Vedovato, L. Fava, S. Marcello, L. Vannucci, Alberto Andrighetto, A. Grasso, V.I. Tretyak, O. Y. Denisov, Alberto Rotondi, Mauro Villa, A. Maggiora, S. De Castro, Antonietta Donzella, Roberto Spighi, M. Lombardi, C. Petrascu, F. D'Isep, D. Parena, Benedetto Giacobbe, Antonio Ferretti, F. Tosello, A. Feliciello, A. Filippi, A. Vezzani, Bruno Minetti, L. Busso, D. Galli, M. Morando, S. Serci, A.M. Rozhdestvensky, E. Rossetto, M.G. Sapozhnikov, A. Vitale, N. Mirfakhraee, Umberto Marini Bettolo Marconi, S. Tessaro, P.P. Temnikov, Massimo Piccinini, Paola Salvini, I. D'Antone, Marco Bruschi, M.P. Bussa, R. A. Ricci, M. Capponi, Stefania Vecchi, V.G. Ableev, D. Panzieri, O.E. Gorchakov, A M Rosca, Alberto Masoni, D. Calvo, V. Lucherini, G. Bendiscioli, F. Balestra, C. Cicalo, N. Semprini Cesari, L. Santi, S. Costa, P. Gianotti, Tullio Bressani, U. Gastaldi, M. BARGIOTTI, A. BERTIN, M. BRUSCHI, M. CAPPONI, A. CARBONE, S. DE CASTRO, R. DONÀ, L. FABBRI, P. FACCIOLI, D. GALLI, B. GIACOBBE, F. GRIMALDI, U. MARCONI, I. MASSA, M. PICCININI, N. SEMPRINI CESARI, R. SPIGHI, S. VECCHI, M. VILLA, A. VITALE, A. ZOCCOLI, M. POLI, A. BIANCONI, M.P. BUSSA, M. CORRADINI, A. DONZELLA, E. LODI RIZZINI, L. VENTURELLI, C. CICALÒ, A. DE FALCO, A. MASONI, G. PUDDU, S. SERCI, G. USAI, O.E. GORCHAKOV, S.N. PRAKHOV, A.M. ROZHDESTVENSKY, M.G. SAPOZHNIKOV, V.I. TRETYAK, P. GIANOTTI, C. GUARALDO, A. LANARO, V. LUCHERINI, C. PETRASCU, R. A. RICCI, V. FILIPPINI, A. FONTANA, P. MONTAGNA, A. PANZARASA, A. ROTONDI, P. SALVINI, A. ZENONI, F. BALESTRA, L. BUSSO, P. CERELLO, O. DENISOV, L. FERRERO, R. GARFAGNINI, A. MAGGIORA, D. PANZIERI, F. TOSELLO, E. BOTTA, T. BRESSANI, D. CALVO, F. DE MORI, A. FELICIELLO, A. FILIPPI, N. MIRFAKHRAI, S. MARCELLO, M. AGNELLO, and F. IAZZI

Subjects
Physics, Annihilation, Physics and Astronomy (miscellaneous), Meson, Hydrogen, Hadron, chemistry.chemical_element, Coincidence, chemistry, Protonium, Isospin, Production (computer science), Atomic physics, Engineering (miscellaneous)
Abstract

The hadronic annihilation branching-ratios in quasi-two-body final states have been obtained from the observation of the reactions pbarp→π+π−π0, K+K−π0,KπK0 at rest in hydrogen targets at different densities. The enhancement or suppression of specific hadronic channels connected to dynamical selection rules is observed in the production of different resonances both in protonium S and P–waves, systematically investigated for the first time. Besides the well known ρ(770)π and a2(1320)π enhancement from 3S1 and 1S0 partial waves, the dominance of one isospin source in K*(892)Kbar production, well established from S–waves, is confirmed also in P–waves (1S0, I = 0; 3S1, I = 1; 1P1, I = 0; 3P1, I = 0; 3P2, I = 1). In addition, the experimental data clearly show a strong suppression of φ(1020)π and a0(980)π final states from P–wave which has a remarkable coincidence with K*(892)Kbar pattern production.

Published
2004

10. 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

11. φπ0 and φη production in antiproton annihilation at rest in a hydrogen gas target at NTP

Author

Ableev, Vg, Agnello, M, Balestra, F, Bendiscioli, G, Bergamaschi, S, Bertin, A, Botta, E, Bressani, T, Bruschi, M, Bussa, Mp, Busso, L, Calvo, D, Capponi, M, Cavion, C, Cereda, B, Cerello, P, Cicalo, C, Corradini, M, Costa, S, Decastro, S, Denisov, Oy, Disep, F, Donzella, A, Fava, L, Feliciello, A, Ferrero, L, Filippi, A, Filippini, V, Fontana, A, Galli, D, Garfagnini, R, Gastaldi, U, Giacobbe, B, Gianotti, P, Gorchakov, Oe, Grasso, A, Guaraldo, C, Iazzi, F, Lanaro, A, Rizzini, El, Lombardi, M, Lucherini, V, Maggiora, A, Marcello, S, Marconi, U, Margagliotti, Gv, Masoni, A, Minetti, B, Montagna, P, Morando, M, Nichitiu, F, Panzieri, D, Parena, D, Pauli, P, Petrascu, C, Piccinini, M, Prakhov, S, Puddu, G, Rosca, A, Rossetto, E, Rotondi, A, Rozhdenstvensky, Am, Saino, A, Salvini, P, Santi, Lorenzo Gianni, Sapozhnikov, Mg, Scoglio, C, Cesari, Ns, Serci, S, Spighi, R, Temnikov, P, Tessaro, S, Tosello, F, Tretyak, Vi, Usai, Gl, Vannucci, L, Vecchi, S, Vedovato, G, Venturelli, L, Villa, M, Vitale, A, Zenoni, A, Zoccoli, A, RI Galli Domenico/A 1606 2012 Iazzi Felice/F 4490 2012 Botta Elena/G 9742 2012 Villa Mauro/C 9883 2009 Fontana Andrea/I 4375 2012 Filippi Alessandra/I 9530 2012, V. G., Ableev, M., Agnello, F., Balestra, G., Bendiscioli, S., Bergamaschi, A., Bertin, E., Botta, T., Bressani, M., Bruschi, M. P., Bussa, L., Busso, D., Calvo, M., Capponi, C., Cavion, B., Cereda, P., Cerello, C., Cicalò, M., Corradini, S., Costa, S., De Castro, Denisov, O. 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, A., Masoni, B., Minetti, P., Montagna, M., Morando, F., Nichitiu, D., Panzieri, D., Parena, P., Pauli, C., Petrascu, M., Piccinini, S., Prakhov, G., Puddu, A., Rosca, E., Rossetto, A., Rotondi, A. M., Rozhdenstvensky, A., Saino, P., Salvini, L., Santi, M. G., Sapozhnikov, C., Scoglio, N., Semprini Cesari, S., Serci, R., Spighi, P., Temnikov, S., Tessaro, F., Tosello, V. I., Tretyak, G. L., Usai, L., Vannucci, S., Vecchi, G., Vedovato, L., Venturelli, M., Villa, A., Vitale, A., Zenoni, and A., Zoccoli

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, P-WAVE, Hydrogen, Branching fraction, OZI-RULE, chemistry.chemical_element, Nuclear physics, Angular distribution, chemistry, OZI rule, OMEGA, Antiproton, PROTON ANNIHILATION, Production rate
Abstract

Data of antiproton annihilation at rest in a hydrogen gas target at NTP have been collected with the Obelix spectrometer exposed to the beam extracted from the LEAR accelerator of CERN. The reactions --> phi pi(0) and --> phi eta have been studied. The analysis of the angular distribution of the kaons emitted by the phi decay has shown that the reaction --> phi pi(0) occurs essentially from S-3(1) states with a production rate R(NTP) = (2.46 +/- 0.23 +/- 0.07) x 10(-4), while the rate from P-1(1) states is compatible with zero. Because of acceptance limitations, S-3(1) and P-1(1) contributions to the reaction --> phi eta could not be resolved and lower and upper limits for the production rate have been measured with the middle value R(NTP) = (0.87 +/- 0.21) x 10(-4). Also, for the phase-space K+ K- eta events the production rate R(NTP) = (4.67 +/- 0.35) x 10(-4) has been measured. The phi pi(0) K and phi eta branching ratios in S- and P-waves (defined in the text) have been estimated in a model dependent way. For the evaluation of the phi eta rate, a combination of our production rate and of data obtained with a liquid target has been used. The phi pi(0) production rate, compared to our preliminary value for the omega pi(0) production, confirms the strong violation of the OZI rule observed in other experiments. No violation is apparent in the phi eta production.

Published
1995

12. 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

13. Annihilation Cross-sections of Antineutrons On C, Al, Cu, Sn and Pb At Low Momenta (180-280 Mev/c) With the Obelix Spectrometer

Author

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

Subjects
Nuclear reaction, Physics, Particle physics, antineutron C annihilation, Large Hadron Collider, Annihilation, Spectrometer, Nucleon-induced reaction and scattering, ANTIPROTON-NUCLEUS INTERACTION, antineutron nuclei annhililation, antineutron Pb annihilation, ELASTIC-SCATTERING, Antineutron, Nuclear physics, antineutron Al annihilation, antineutron Sn annihilation, C/AL, antineutron Cu annihilation, General Agricultural and Biological Sciences, computer, computer.programming_language
Abstract

Annihilation cross-sections sigma(ann) for antineutrons on some nuclei (C, Al, Cu, Sn and Pb) at three antineutron momenta (180, 240 and 280 MeV/c) were measured at LEAR (CERN) with the OBELIX spectrometer. A behaviour sigma(ann) = = sigma0A(nu) has been found with nu almost-equal-to 2/3. The data are discussed following some models for antineutron-nucleus interaction.

Published
1994

14. 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

15. An experimental study of antiproton-4He annihilation at rest

Author

Adamo, A, Agnello, M, Balestra, F, Belli, G, Bendiscioli, G, Bertin, A, Boccaccio, P, Bonazzola, Gc, Bressani, T, Bruschi, M, Bussa, Mp, Busso, L, Calvo, D, Capponi, M, Cerello, P, Cicalo, C, Costa, S, Decastro, S, Disep, F, Donzella, A, Fava, L, Feliciello, A, Ferrero, L, Filippi, A, Filippini, V, Galli, D, Garfagnini, R, Gastaldi, U, Gianotti, P, Grasso, A, Guaraldo, C, Iazzi, F, Kharzeev, De, Lanaro, A, LODI RIZZINI, E, Lombardi, M, Lucherini, V, Maggiora, A, Marcello, S, Marconi, U, Margagliotti, Gv, Maron, G, Masoni, A, Massa, I, Minetti, B, Montagna, P, Morando, M, Nichitiu, F, Panzieri, D, Pauli, P, Piccinini, M, Piragino, G, Poli, M, Puddu, G, Ricci, Ra, Rossetto, E, Rotondi, A, Rozhdenstvensky, Am, Saino, A, Salvini, P, Santi, Lorenzo Gianni, Sapozhnikov, Mg, SEMPRINI CESARI, N, Serci, S, Spighi, R, Temnikov, Pp, Tessaro, S, Tosello, F, Tretyak, Vi, Usai, Gl, Vannucci, L, Vecchi, S, Vedovato, G, Venturelli, L, Villa, M, Vitale, A, Zenoni, A, Zoccoli, A, Zosi, G, RI Galli Domenico/A 1606 2012 Iazzi Felice/F 4490 2012 Villa Mauro/C 9883 2009 Filippi Alessandra/I 9530 2012, 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, P., Cerello, C., Cicalò, S., Costa, 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, D. E., Kharzeev, 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, P., Pauli, M., Piccinini, G., Piragino, M., Poli, G., Puddu, R. A., Ricci, E., Rossetto, A., Rotondi, A. M., Rozhdenstvensky, A., Saino, P., Salvini, L., Santi, M. G., Sapozhnikov, N., Semprini Cesari, S., Serci, R., Spighi, P. P., Temnikov, S., Tessaro, 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 reaction, Nuclear and High Energy Physics, STRANGENESS PRODUCTION, Annihilation, He target, STOPPED ANTIPROTONS, Nuclear physics, Pion, Pair production, Deuterium, Antiproton, Invariant mass, Atomic physics, Nuclear Experiment, Nucleon, antiproton annihilation
Abstract

This paper reports new experimental results on the annihilation of antiprotons stopped in a He-4 gas target. The measurement was carried out with the Obelix spectrometer installed at the LEAR machine of CERN. Main results can be-summarized as follows. (i) The invariant mass distribution of 2pi+2pi- produced at rest is similar to those from hydrogen and deuterium targets: the peak seen in recent experiments around 1150 MeV/c2 is absent. (ii) 2pi angular correlations are very close to those found for hydrogen. The nuclear structure does not modify remarkably the pion production and emission. (iii) pip and pp angular correlations are strongly peaked close to 180-degrees, in qualitative agreement with INC model predictions. (iv) The pp invariant mass distribution reveals events which may be due to eta(omega) absorption; the estimated upper limit for probability of eta and omega absorption is about 3 x 10(-3). (v) Events having features compatible with two-nucleon annihilations with production of heavy mesonic systems are detected both in the 2pi+2pi- and the 2pi-pi+ channels. The production rate of the 2pi+2pi-channel is of the order of 5 x 10(-3).

Published
1994

16. 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

17. 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

18. 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

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