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10 results on '"L., Venturelli"'

1. Limits on antiproton-nuclei annihilation cross sections at ∼125 keV

Author

E. Vallazza, D. Seiler, D. De Salvador, Daniel Barna, Masaki Hori, M. Leali, Ryugo S. Hayano, M. Corradini, M. Prest, L. Venturelli, Anna Sótér, E. Lodi-Rizzini, Valerio Mascagna, K. Todoroki, and Hossein Aghai-Khozani

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Annihilation, 010308 nuclear & particles physics, media_common.quotation_subject, Kinetic energy, 01 natural sciences, Asymmetry, Nuclear physics, Antiproton, Antimatter, 0103 physical sciences, 010306 general physics, media_common
Abstract

Some experimental limits on the annihilation cross sections σ ann of antiprotons on carbon, palladium, and platinum targets were determined at the previously unexplored kinetic energy region E ≈ 125 keV. Information on σ ann at such low antiproton energies is important in understanding the dynamics of the annihilation process, and provides useful data for models that attempt to describe the matter-antimatter asymmetry in the universe by assuming the existence of islands of antimatter concentration.

Published
2021

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

Author

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

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

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

Published
2006

3. 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

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

Author

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

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

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

Published
2002

5. Contribution from and waves in annihilation at rest

Author

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

Subjects
Nuclear physics, Physics, Nuclear reaction, Nuclear and High Energy Physics, Annihilation, Protonium, Branching fraction, Excited state, Hadron, Atomic physics, Exotic atom
Abstract

The annihilation frequencies of 19 p p annihilation reactions at rest obtained in different target densities are analysed in order to determine the values of the P -wave annihilation percentage at each target density and the average hadronic branching ratios from P - and S -states. Both the assumptions of linear dependence of the annihilation frequencies on the P -wave annihilation percentage of the protonium state and the approach with the enhancement factors of Batty are considered. Furthermore the cases of incompatible measurements are discussed.

Published
2001

6. Study of and annihilation reactions in flight

Author

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

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

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

Published
1999

7. Measurements of the annihilation at rest

Author

S. Costa, R. Spighi, A. Masoni, Elena Botta, Felice Iazzi, S. Marcello, S. De Castro, A. Filippi, Paola Salvini, F. Balestra, Corrado Cicalo, R. A. Ricci, Maurizio Piccinini, G. Puddu, Sergio Serci, Michelangelo Agnello, M. Capponi, M. Poli, Tullio Bressani, M. Lombardi, Piergiorgio Cerello, U. Gastaldi, G. Vedovato, V. Lucherini, M.G. Sapozhnikov, A. Saino, D. Calvo, A. Maggiora, V.I. Tretyak, G. Maneva, Paolo Montagna, C. Guaraldo, O.E. Gorchakov, B. Cereda, R. Garfagnini, P. Boccaccio, M.P. Bussa, Paola Gianotti, F. Nichitiu, V.G. Ableev, F. Tosello, S. Tessaro, M. Morando, Stefania Vecchi, Gianfranco Zosi, E. Rossetto, G. L. Usai, L. Vannucci, Adriano Fontana, G. Pauli, L. Ferrero, A. Feliciello, Armando Lanaro, S.N. Prakhov, L. Busso, L. Santi, A. Vitale, D. Galli, Petar Temnikov, Mauro Villa, G. V. Margagliotti, Antonietta Donzella, D. D'Isep, Bruno Minetti, Alberto Rotondi, E. Lodi Rizzini, B. Giacobbe, A. Bertin, Nicola Semprini-Cesari, O.Yu. Denisov, D. Panzieri, V. Filippini, A.M. Roshdestvensky, A. Grasso, Aldo Zenoni, G. Bendiscioli, Marco Bruschi, L. Fava, U. Marconi, G. Maron, L. Venturelli, and Antonio Zoccoli

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Nuclear magnetic resonance, Analytical chemistry
Abstract

The measurement of different reactions of p d annihilation at rest in a gaseous target has been performed using the OBELIX spectrometer at LEAR (CERN). A strong deviation from the OZI-rule prediction was found from the measurement of the ratio R = φπ ωπ in two regions of proton momenta, P c and P > 400 MeV/ c : R( φπ − ωπ − ) = (133 ± 26) × 10 −3 and (113 ± 30) × 10 −3 , respectively. These values are about 30 times greater than the theoretical prediction. For the first time the excitation of the †-resonance was observed among the final-state products of p d annihilation. The existence of a broad enhancement in the 4π invariant mass at m ≈ 1480 MeV, seen in previous experiments, was confirmed. A ≈ 100 MeV downward shift of the bump position, when the proton momentum increased up to P > 400 MeV/ c , was also observed, while the positions of ω, ϱ and f 2 (1270) did not change with the proton momentum. The following branching ratios were measured: BR( p d → π − φ p ) = (6.62 ± 0.49) × 10 −4 , for P c ; BR( p d → π − φ p ) = (0.95 ± 0.22) × 10 −4 , for P > 400 MeV/ c ; BR( p d → π − ω p ) = (49.7 ± 8.9) × 10 −4 , for P c ; BR( p d → π − ω p ) = (8.38 ± 1.09) × 10 −4 , for P > 400 MeV/ c ; BR( p d → 2π − π + p ) = (150 ± 6) × 10 −4 , for P c ; BR( p d → 2π − π + p ) = (16.6 ± 0.9) × 10 −4 , for P > 400 MeV/ c ; BR( p d → 3π − 2π + p ) = (326 ± 12) × 10 −4 , for P c ; BR( p d → 3π − 2π + p ) = (44 ± 7) × 10 −4 , for P > 400 MeV/ c ; BR( p d → Λ K + π − ) = (0.96 ± 0.19) × 10 −4 , for P > 400 MeV/ c ; BR( p d → Λ K + π − π 0 ) = (3.5 ± 0.8) × 10 −4 , for P > 400 MeV/ c ; BR( p p → 2π − 2π + ) = (540 ± 20) × 10 −4 ; BR( p p → 3π − 3π + ) = (251 ± 21) × 10 −4 .

Published
1995

8. FINUDA and hypernuclei production at DAωNE

Author

N. Colonna, L. Fiore, Rinaldo Rui, S. Marcello, M. Bertani, A. Donzella, Felice Iazzi, D. R. Gill, A. Sharma, Paola Salvini, A. Olin, L. Venturelli, E. Rossetto, D. Calvo, Bruno Minetti, S. Sarwar, C. Guaraldo, S. Yen, S. Bianco, S. Costa, Paolo Montagna, G. D’Erasmo, N. Grion, Elena Botta, V. Lucherini, Paolo Camerini, Michelangelo Agnello, Armando Lanaro, G. R. Smith, P. Gianotti, V. Paticchio, A. Feliciello, L. Busso, Tullio Bressani, A. Filippi, E.M. Fiore, M. Corradini, V. Filippini, Aldo Zenoni, E. Lodi-Rizzini, C. Cattaneo, Alberto Rotondi, F.L. Fabbri, and A. Pantaleo

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Positron, Luminosity (scattering theory), law, Electron, Collider, Linear particle accelerator, law.invention
Abstract

The DAωNE project at the Laboratori Nazionali di Frascati (LNF) is an e + e − collider with electron and positron beams accelerated to 510 MeV by a Linac injector. DAωNE is designed to reach a top luminosity L ∼ 10 33 cm −2 s −1 , that is, to produce ∼4×10 3 ω (1020) s −1 . The hypernuclear research program at DAωNE relies on low-energy kaons, ∼ 16MeV, being produced by ω-meson decays at rest: ω → K − K + with a B.R.∼49%. In the initial stage, DAωNE will operate at a L ∼ 10 32 cm −2 s −1 , however the number of ω produced, and the large geometrical acceptance of the FINUDA detector, ∼ 3 sr , will allow a strong hypernuclear physics program to be pursued.

Published
1995

9. stopping power in hydrogen below 1 MeV and the 4He metastable state

Author

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

Subjects
Physics, Nuclear and High Energy Physics, chemistry, Hydrogen, Gas pressure, Spectrometer, Metastability, Energy interval, Low density, chemistry.chemical_element, Stopping power, Atomic physics, Helium
Abstract

The stopping power of H, for p S was measured in the p energy interval 1 keV + 120 keV using a low density gas target ( p pρ ≈ l0 −3 + 10 −2 ÷ pρ being the Hz density at STP) with the OBELIX spectrometer at the LEAR of CEBN. Furthermore, the formation of metastable states in the p 4 He interaction at rest, having a mean life of the order of 3 μs, was investigated at six target gas pressures (3 atm and 400,250,200,150,50 mbar). The influence of contaminants (like Ha, Ne, Ar, N2 and Xe) on the life of such metastable states was examined at the target gas pressure of 3 atm.

Published
1993

10. Hypernuclear physics at DAφNE, the frascati φ-factory

Author

P. Gianotti, F. D'Isep, Tullio Bressani, Alessandro Feliciello, S. Costa, Daniela Calvo, C. Guaraldo, Michelangelo Agnello, E. Lodi Rizzini, Felice Iazzi, S. Marcello, G.C. Bonazzola, L. Venturelli, V. Lucherini, A. Lanaro, Bruno Minetti, and E. Rossetto

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Spectrometer, Field (physics), Detector, Factory (object-oriented programming), High resolution
Abstract

The low-energy, background free and tagged K−s from the φ(1020) decay produced at the DAφNE φ-factory in Frascati offer a unique opportunity for high resolution hypernuclei spectroscopy with K−at rest. In this paper we outline the general problematics of this interesting field, expose the physics motivations that support our proposal and, finally, describe the techniques foreseen for precise measurements of the hypernuclear level energies and their decay modes. In this regard we investigated the performances of a magnetic spectrometer foreseen for] one of the interaction region of the DAφNE machine. Details on the detector characteristics as well as on its response to all the particles in the final state will be extensively discussed.

Published
1992

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