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206 results on '"Tullio Bressani"'

1. On the binding energy and the charge symmetry breaking in A ≤ 16 Λ-hypernuclei

Author

Elena Botta, A. Feliciello, and Tullio Bressani

Subjects
Physics, Charge Symmetry Breaking effect, Nuclear and High Energy Physics, Binding energy, Λ-hypernuclei, Spectrometer, Series (mathematics), Field (physics), 010308 nuclear & particles physics, Charge (physics), Scale (descriptive set theory), 01 natural sciences, Nuclear physics, 0103 physical sciences, Symmetry breaking, Nuclear Experiment, 010306 general physics, Energy (signal processing)
Abstract

In recent years, several experiments using magnetic spectrometers provided high precision results in the field of Hypernuclear Physics. In particular, the accurate determination of the Lambda-binding energy, B(Lambda), contributed to stimulate considerably the discussion about the Charge Symmetry Breaking effect in Lambda-hypernuclei isomultiplets. We have reorganized the results from the FINUDA experiment and we have obtained a series of B(Lambda) values for Lambda-hypernuclei with A, Comment: 22 pages, 5 figures

Published
2017
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3. Results on Λp emission from K− absorption at rest on light nuclei

Author

A. Filippi, F. Moia, R. Wheadon, P. Genova, H. Fujioka, O. Morra, Paolo Camerini, N. Grion, A. Pantaleo, Rinaldo Rui, S. Marcello, P. Gianotti, Paolo Montagna, B. Dalena, V. Paticchio, E. M. Fiore, D. Calvo, F. De Mori, Haruhiko Outa, Hyoungchan Bhang, Luigi Benussi, Elena Botta, Germano Bonomi, A. Feliciello, M. Bertani, L. Busso, V. Lucherini, Andrea Fontana, Tullio Bressani, Marco Bregant, Aldo Zenoni, F. L. Fabbri, Michelangelo Agnello, N. Mirfakhrai, Tomofumi Nagae, G. DʼErasmo, Stefania Bufalino, Stefano Piano, and G. Simonetti

Subjects
Nuclear physics, Physics, Rest (physics), Nuclear and High Energy Physics, Light nucleus, Atomic physics, Absorption (electromagnetic radiation)
Abstract

The analysis of the first FINUDA paper on the emission of Λp pairs following the K − absorption at rest on 6Li, 7Li, 12C nuclei has been revised by using a much larger data set and an updated analysis techniques. The preliminary results regarding the Be 9 ( K stop − , Λ p ) X reaction are discussed.

Published
2013
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4. The A(Kstop−,π±Σ∓)A′ reaction on p-shell nuclei

Author

P. Genova, F. L. Fabbri, A. Feliciello, L. Busso, Rinaldo Rui, S. Marcello, Luigi Benussi, D. Calvo, Aldo Zenoni, Paolo Montagna, Tomofumi Nagae, Hiroyuki Fujioka, Andrea Fontana, F. Moia, B. Dalena, A. Filippi, V. Lucherini, Germano Bonomi, Stefania Bufalino, Elena Botta, H. C. Bhang, Michelangelo Agnello, P. Gianotti, E. M. Fiore, O. Morra, G. DʼErasmo, V. Paticchio, Marco Bregant, Stefano Piano, G. Simonetti, A. Pantaleo, Tullio Bressani, N. Mirfakhrai, Haruhiko Outa, Paolo Camerini, F. De Mori, M. Bertani, R. Wheadon, and N. Grion

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Reaction mechanism, Pion, Spectrometer, Hydrogen, chemistry, Pi, Sigma, chemistry.chemical_element, Atomic physics, Spectral line
Abstract

This Letter is concerned with the study of the K stop − A → π ± Σ ∓ A ′ reaction in p-shell nuclei, i.e., 6,7 Li, 9 Be, 13 C and 16 O. The π ± Σ ∓ / K stop − emission rates are reported as a function of A . These rates are discussed in comparison with previous findings. The ratio π − Σ + / π + Σ − in p-shell nuclei is found to depart largely from that on hydrogen, which provides support for large in-medium effects possibly generated by the sub-threshold Λ ( 1405 ) . The continuum momentum spectra of prompt pions and free sigmas are also discussed as well as the π ± Σ ∓ missing mass behavior and the link with the reaction mechanism. The apparatus used for the investigation is the FINUDA spectrometer operating at the DA Φ NE ϕ -factory (LNF-INFN, Italy).

Published
2011
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5. Neutron-proton coincidences from Non-Mesonic Weak Decay of p-shell Λ-hypernuclei and determination of the two-nucleon induced process

Author

Germano Bonomi, Aldo Zenoni, P. Gianotti, F. L. Fabbri, Stefania Bufalino, M. Bregant, V. Lucherini, V. Paticchio, G. Garbarino, Michelangelo Agnello, O. Morra, R. Wheadon, Luigi Benussi, E. M. Fiore, B. Dalena, Haruhiko Outa, Tullio Bressani, Tomofumi Nagae, A. Filippi, D. Calvo, G. DʼErasmo, N. Mirfakhrai, Stefano Piano, G. Simonetti, N. Grion, Rinaldo Rui, S. Marcello, F. De Mori, M. Bertani, Paolo Camerini, P. Genova, Hiroyuki Fujioka, Elena Botta, H. C. Bhang, L. Busso, A. Pantaleo, Paolo Montagna, A. Feliciello, F. Moia, M., Agnello, L., Benussi, M., Bertani, H. C., Bhang, G., Bonomi, E., Botta, M., Bregant, T., Bressani, S., Bufalino, L., Busso, D., Calvo, Camerini, Paolo, B., Dalena, F., De Mori, G., D’Erasmo, F. L., Fabbri, A., Feliciello, A. Filippib E. M., Fiore, H., Fujioka, P., Genova, P., Gianotti, N., Grion, V., Lucherini, S., Marcello, N., Mirfakhrai, F., Moia, P., Montagna, O., Morra, T., Nagae, H., Outa, A., Pantaleo, V., Paticchio, S., Piano, Rui, Rinaldo, G., Simonetti, R., Wheadon, A., Zenoni, and G., Garbarino

Subjects
Nuclear and High Energy Physics, Particle physics, Proton, Nuclear Theory, Shell (structure), Λ-hypernuclei, weak decays, 01 natural sciences, Spectral line, Two nucleon induced decay, Delta baryon, Nuclear physics, Non-mesonic weak decay, 0103 physical sciences, Neutron, Λ-hypernuclei, Non-mesonic weak decay, Two nucleon induced decay, 010306 general physics, Lambda-hypernuclei, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Hypernucleus, Charged particle, High Energy Physics::Experiment, Nucleon, Hypernuclear physics
Abstract

The decay of Λ -hypernuclei without π emission, known as Non-Mesonic Weak Decay (NMWD), gives an effective tool to investigate Δ S = 1 four-baryon interactions. It was theoretically suggested that the two-nucleon induced mechanism could play a substantial role in reproducing the observed NMWD decay rates and nucleon spectra, but at present no direct evidence of such a mechanism has been obtained. The FINUDA experiment, exploiting the possibility to detect both charged and neutral particles coming from the hypernucleus decay, has allowed us to deduce the relative weight of the two nucleon induced decay rate to the total NMWD rate. The value of Γ 2 N / Γ NMWD = 0.21 ± 0.07 stat − 0.02 sys + 0.03 sys has been deduced, well consistent with the previous determinations.

Published
2011

6. HPGe in Magnetic Fields

Author

Tullio Bressani and A. Feliciello

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Nuclear magnetic resonance, chemistry, Detector, chemistry.chemical_element, Germanium, Spectroscopy, Order of magnitude, Semiconductor detector, Magnetic field
Abstract

The advent of high purity germanium (HPGe) crystals more than 40 years ago represents a fundamental milestone in experimental Nuclear Physics: the new detectors, capable of featuring an energy resolution superior by more than an order of magnitude with respect to other devices, led to a new level of γ-ray spectroscopy data quality. In the last few years it has been experimentally proven that hypernuclear spectroscopy can benefit from the same advantages as well [1, 2].

Published
2010
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7. The Latest Developements of Strangeness Nuclear Physics

Author

Tullio Bressani

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Strange quark, Particle properties, Field (physics), J-PARC, Strangeness
Abstract

A short review of the more interesting new results presented at the HYP-X Conference is given, with emphasis on the perspectives of the field, in particular at the new complex of machines J-PARC.

Published
2010
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8. Study of the reaction

Author

P. Gianotti, V. Paticchio, V. Lucherini, A. Feliciello, Michelangelo Agnello, A. Pantaleo, H. Fujioka, Paolo Camerini, P. Genova, F. L. Fabbri, Stefano Piano, Aldo Zenoni, L. Busso, G. D'Erasmo, G. Simonetti, F. Moia, E. Bonifazi, B. Dalena, Germano Bonomi, D. Calvo, F. De Mori, Tomofumi Nagae, Elena Botta, Paolo Montagna, Haruhiko Outa, H. C. Bhang, F. Pompili, Rinaldo Rui, S. Marcello, A. Filippi, Akihiro Toyoda, M. Bertani, Richard Wheadon, Tomofumi Maruta, Marco Bregant, D. Nakajima, Luisa Benussi, B. H. Kang, Tullio Bressani, N. Mirfakhrai, E. M. Fiore, N. Grion, and Stefania Bufalino

Subjects
Momentum, Physics, Nuclear and High Energy Physics, Light nucleus, Spectrometer, Spectrum (functional analysis), Interval (graph theory), Atomic physics
Abstract

This contribution describes a recent experimental study of the A ( K s t o p − , π ± Σ ∓ ) A ′ reaction on light nuclei, Li 6 , 7 , Be 9 , C 13 and O 16 . Final π ± Σ ∓ pairs arise from π + π − n events. For some nuclei, the π + momentum spectrum presents peak-strucures in the kinematical interval of formation of Σ-hypernuclear states. The apparatus used for the investigation is the FINUDA spectrometer set at DAΦNE.

Published
2010
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9. Proton spectra from Non-Mesonic Weak Decay of p-shell Λ-hypernuclei and evidence for the two-nucleon induced process

Author

A. Andronenkov, F. L. Fabbri, Haruhiko Outa, V. Lenti, P. Genova, D. Calvo, Aldo Zenoni, Michiko Sekimoto, R. Wheadon, G. D'Erasmo, Tullio Bressani, N. Grion, Paolo Camerini, M. Palomba, O. Morra, E. M. Fiore, G. A. Beer, V. Lucherini, N. Mirfakhrai, A. Filippi, Michelangelo Agnello, O. Hartmann, F. De Mori, Akihiro Toyoda, G. Simonetti, Paola Gianotti, Luigi Benussi, D. Nakajima, Stefania Bufalino, E. Pace, M. Bertani, B. Dalena, Andrea Fontana, G. Garbarino, Tomofumi Maruta, A. Panzarasa, L. Busso, Paolo Montagna, Marco Bregant, A. Pantaleo, Rinaldo Rui, S. Marcello, S. Piano, V. Paticchio, F. Pompili, A. Feliciello, Germano Bonomi, Tomofumi Nagae, Hiroyuki Fujioka, Elena Botta, H. C. Bhang, M., Agnello, A., Andronenkov, G., Beer, L., Benussi, M., Bertani, H. C., Bhang, G., Bonomi, E., Botta, M., Bregant, T., Bressani, S., Bufalino, L., Busso, D., Calvo, Camerini, Paolo, B., Dalena, F., De Mori, G., D'Erasmo, F. L., Fabbri, A., Feliciello, A., Filippi, E. M., Fiore, A., Fontana, H., Fujioka, P., Genova, P., Gianotti, N., Grion, O., Hartmann, V., Lenti, V., Lucherini, S., Marcello, T., Maruta, N., Mirfakhrai, P., Montagna, O., Morra, T., Nagae, D., Nakajima, H., Outa, E., Pace, M., Palomba, A., Pantaleo, A., Panzarasa, V., Paticchio, S., Piano, F., Pompili, Rui, Rinaldo, M., Sekimoto, G., Simonetti, A., Toyoda, R., Wheadon, A., Zenoni, and G., Garbarino

Subjects
Mass number, Physics, Nuclear and High Energy Physics, Range (particle radiation), Proton, Branching fraction, Nuclear Theory, Shell (structure), FOS: Physical sciences, lambda hypernuclei, Kinetic energy, Spectral line, Nuclear physics, non-mesonic decay, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Atomic physics, Nucleon, Nuclear Experiment
Abstract

New spectra from the FINUDA experiment of the Non Mesonic Weak Decay (NMWD) proton kinetic energy for 9(Lambda)Be, 11(Lambda)B, 12(Lambda)C, 13(Lambda)C, 15 (Lambda)N and 16(Lambda)O are presented and discussed along with the published data on 5(Lambda)He and 7(Lambda)Li. Exploiting the large mass number range and the low energy threshold (15 MeV) for the proton detection of FINUDA, an evaluation of both Final State Interactions (FSI) and the two nucleon induced NMWD contributions to the decay process has been done. Based on this evaluation, a linear dependence of FSI on the hypernuclear mass number A is found and for the two nucleon stimulated decay rate the experimental value of Gamma2/Gammap=0.43+-0.25 is determined for the first time. A value for the two nucleon stimulated decay rate to the total decay rate Gamma2/GammaNMWD=0.24+-0.10 is also extracted., 11 pages and 2 figures

Published
2010

10. The search for antikaon nuclear bound states, recent results from FINUDA

Author

A. Andronenkov, Luigi Benussi, Tomofumi Nagae, D. Calvo, D. Nakajima, Germano Bonomi, Michiko Sekimoto, A. Pantaleo, Tullio Bressani, V. Lucherini, Tomofumi Maruta, V. Paticchio, Stefano Piano, Michelangelo Agnello, O. Morra, G. Simonetti, Rinaldo Rui, S. Marcello, N. Mirfakhrai, E. Bonifazi, Paolo Camerini, A. Filippi, E. M. Fiore, Paolo Montagna, E. Botta, Akihiro Toyoda, G. D'Erasmo, R. Wheadon, Haruhiko Outa, P. Genova, B. Dalena, N. Grion, Aldo Zenoni, V. Lenti, M. Palomba, F. De Mori, A. Panzarasa, L. Busso, Stefania Bufalino, E. Pace, M. Bertani, F. L. Fabbri, Paola Gianotti, F. Pompili, A. Feliciello, Andrea Fontana, G. A. Beer, O. Hartmann, B. H. Kang, Marco Bregant, A. S. Lorente, Hiroyuki Fujioka, and H. C. Bhang

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Light nucleus, dynamics, systems, pairs, Spectrometer, Bound state, General Physics and Astronomy
Abstract

Novel data from the [Formula: see text] absorption reaction in light nuclei are presented. The data were collected by the FINUDA spectrometer running at the DAΦNE ϕ-facility, Laboratori Nazionali di Frascati (LNF), Italy.

Published
2010

11. Study of two-body non-mesonic decays of light hypernuclei with FINUDA

Author

Haruhiko Outa, B. Dalena, Tullio Bressani, F. L. Fabbri, N. Mirfakhrai, Andrea Fontana, Germano Bonomi, F. Moia, Stefano Piano, G. Simonetti, Paolo Camerini, R. Wheadon, E. M. Fiore, D. Calvo, N. Grion, V. Paticchio, F. De Mori, P. Genova, Tomofumi Nagae, G. D'Erasmo, D. Nakajima, Luigi Benussi, B. H. Kang, Rinaldo Rui, S. Marcello, E. Botta, V. Lucherini, M. Bertani, O. Morra, A. Filippi, Akihiro Toyoda, Michelangelo Agnello, Stefania Bufalino, Marco Bregant, Paola Gianotti, H. C. Bhang, F. Pompili, A. Feliciello, Aldo Zenoni, L. Busso, A. Pantaleo, Tomofumi Maruta, Hiroyuki Fujioka, M., Agnello, L., Benussi, M., Bertani, H. C., Bhang, G., Bonomi, E., Botta, M., Bregant, T., Bressani, S., Bufalino, L., Busso, D., Calvo, Camerini, Paolo, B., Dalena, F., De Mori, G., D'Erasmo, F. L., Fabbri, A., Feliciello, A., Filippi, E. M., Fiore, A., Fontana, H., Fujioka, P., Genova, P., Gianotti, N., Grion, B., Kang, V., Lucherini, S., Marcello, T., Maruta, N., Mirfakhrai, F., Moia, O., Morra, T., Nagae, D., Nakajima, H., Outa, A., Pantaleo, V., Paticchio, S., Piano, F., Pompili, Rui, Rinaldo, G., Simonetti, A., Toyoda, R., Wheadon, and A., Zenoni

Subjects
Physics, Nuclear physics, Non Mesonic Weak Decay, Nuclear and High Energy Physics, hypernucleu, hypernucleus, non-mesonic decay, Light Hypernuclei, High Energy Physics::Experiment, Nuclear Experiment, Branching (polymer chemistry)
Abstract

The Non-Mesonic two-body decays He Λ 4 → d d , p t and He Λ 5 → d t have been studied by the FINUDA experiment. The branching ratios for these rare decay channels are given.

Published
2010

12. Quark deconfinement in antiproton annihilation at rest on light nuclei

Author

A. Panzarasa, G. Bendiscioli, Tullio Bressani, L. Lavezzi, and P. Salvini

Subjects
Physics, Quark, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Hadron, Strangeness production, Condensed Matter Physics, Deconfinement, Atomic and Molecular Physics, and Optics, Nuclear physics, Production (computer science), Physical and Theoretical Chemistry, Nucleon
Abstract

We experimentally investigated the dependence of the K + and K − production on the number of nucleons involved in the annihilation process at rest on 3He and 4He gas targets comparing the results with \(\overline p^1H\) and \(\overline p^2H\) annihilation data: all events were collected by the Obelix experiment, in operation at LEAR until 1996. Events with and without production of neutral mesons and with and without emission of fast neutrons (that is neutrons involved in the annihilation process) are recognized. The results are consistent with our previous ones on a more restricted sample of annihilation reactions on 4He and put in evidence that the strangeness production is lower or higher depending on the reaction channel. As a general trend, the strangeness production is higher in events with the involvement of a higher number of nucleons. The maximum K + production is observed in the reaction \(\overline p ^4He \rightarrow K^+ 2\pi^+ 2\pi^- 3n\) (with the involvement of 3–4 nucleons): compared with the reaction on hydrogen \(\overline p p \rightarrow K^+ 2\pi^+ 2\pi^- \) the production on 4He is higher by a factor of 31.7 ± 5.5. In the light of some theoretical speculations this enhancement is too high to be explainable in terms of hadronic interactions and could be interpreted as a signature of quark deconfinement or possibly of QGP formation.

Published
2009
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13. KAIUM at DAΦNE?

Author

V. Lucherini, Tullio Bressani, and Adriano Fontana

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Series (mathematics), CPT symmetry, Hydrogen isotope, Observable, Physical and Theoretical Chemistry, Condensed Matter Physics, Short duration, Atomic and Molecular Physics, and Optics, Exotic atom
Abstract

The possibility of producing and detecting at DAΦNE a new hydrogen isotope formed by a (K + e − ) bound system (Kaium) is addressed, considering a dedicated, and relatively simple experiment of short duration. If Kaium will be detected, it could in perspective pave the way for a series of highly sophisticated experiments focused on the precision measurement of several observables, as the K + − K − mass difference, strictly related to CPT invariance.

Published
2009
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14. OBELIX results on Kaonic Nuclear Clusters production by antiproton annihilation at rest on 4He

Author

G. Bendiscioli, Paola Salvini, L. Lavezzi, A. Panzarasa, and Tullio Bressani

Subjects
Rest (physics), Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Antiproton, Production (computer science), Physical and Theoretical Chemistry, Condensed Matter Physics, Atomic and Molecular Physics, and Optics
Abstract

Experimental results recently obtained by OBELIX on the possible production of Kaonic Nuclear Clusters by \(\overline{p}\) annihilation on 4He are critically revised and compared with analogous results from experiments with stopped K −. The use of \(\overline{p}\) instead than K − at rest on nuclei in the search of the existence and properties of such objects seems better, both from the experimental side and the discovery potential.

Published
2009
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15. Antikaon interactions in nuclei (Experiment)

Author

Tullio Bressani

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Atomic physics, Nucleon, Absorption (electromagnetic radiation)
Abstract

Recent results on mesonless absorption of stopped K − by 2,3,4 nucleons are discussed. It is possibly related to the existence of antikaon–nuclear quasibound states. Short reviews of the theoretical effort and on results from measurements with other reactions are presented. An outlook of the information that should be obtained in the near future is finally given.

Published
2009
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16. A new analysis improving the evidence of a narrow peak in the invariant-mass distribution of the $ \Lambda$ p system observed in the $ \bar{{p}}$ annihilation at rest on 4He

Author

Tullio Bressani, P. Salvini, G. Bendiscioli, and L. Lavezzi

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Binding energy, Hadron, Invariant mass, Atomic physics, Lambda, Upper and lower bounds, P system, Bar (unit)
Abstract

The presence of a narrow peak in the $ \Lambda$ p invariant-mass distribution observed in the $ \bar{{p}}$ annihilation reaction at rest $\ensuremath \bar{p} {}^4\mathrm{He}\rightarrow p\pi^-p\pi^+\pi^-n X$ is discussed again through an analysis procedure which improves the ratio signal/background in comparison with the previous analysis. The peak is centred at 2223.2±3.2stat±1.2syst MeV and has a statistical significance of 4.7 $ \sigma$ , values compatible with those published previously. If interpreted as the result of the decay into $ \Lambda$ p of a $\ensuremath { }_{\bar{K}}{}^2\mathrm{H}$ bound system, the corresponding binding energy should be B = - 151.0±3.2stat±1.2syst MeV and the width $ \Gamma_{{FWHM}}^{}$ < 33.9±6.2 MeV. The production rate has a lower limit of 1.2 10-4. Data on the $ \bar{{p}}$ annihilation reaction at rest $ \bar{{p}}$ 4He $ \rightarrow$ p $ \pi^{-}_{}$ p $ \pi^{-}_{}$ p s X , analyzed for the first time, lead to a result in qualitative agreement with the previous one.

Published
2009
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17. High strangeness production in antiproton annihilation at rest on few nucleon systems as a possible signature of quark deconfinement or QGP occurrence

Author

A. Panzarasa, Paola Salvini, Tullio Bressani, G. Bendiscioli, and L. Lavezzi

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Nuclear Theory, Hadron, Strangeness production, Deconfinement, Nuclear physics, Pion, Nuclear Experiment, Nucleon
Abstract

The dependence of the K + and K − production on the number of nucleons involved in the annihilation process is investigated experimentally in the p ¯ annihilation at rest on hydrogen, deuterium, 3He and 4He gas targets. Annihilations with any number of prongs (charged pions and kaons, protons and deuterons) are analyzed. Events with and without production of neutral mesons and with and without emission of fast neutrons (that is neutrons involved in the annihilation process) are recognized. The results are consistent with our previous ones on a more restricted sample of annihilation reactions and put in evidence that the strangeness production is lower or higher depending on the reaction channel. As a general trend, the strangeness production is higher in events without neutral mesons and still higher in events with the involvement of a higher number of nucleons. Both K + and K − productions increase with the number of involved nucleons, but K + much more. The maximum K + production is observed in the reaction K + 2 π + 2 π − 3 n on 4He (with the involvement of 3–4 nucleons); compared with the production on hydrogen in the reaction K + π + 2 π − , the production on 4He is higher by a factor of 31.7 ± 5.5 . In the light of some theoretical speculations, this enhancement factor is too high to be explainable in terms of hadronic interactions and could be interpreted as a signature of quark deconfinement and of formation of a quark–gluon plasma.

Published
2009
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18. Recent results on antiproton annihilation in 4He

Author

A. Panzarasa, Andrea Fontana, Alberto Rotondi, Paolo Montagna, P. Salvini, Tullio Bressani, L. Lavezzi, and G. Bendiscioli

Subjects
Physics, Particle physics, Annihilation, Nuclear Theory, Strangeness production, Atomic and Molecular Physics, and Optics, Pentaquark, Nuclear physics, Baryon, Antiproton, Bound state, Production (computer science), Nuclear Experiment, Nucleon
Abstract

With experimental data of ${\bar p}$ annihilation at rest on nuclei of 4He, collected by the Obelix spectrometer (LEAR, CERN), we have studied a number of reactions with 4 and 5 charged particles in the final state, distinguishing the annihilations on more than one nucleon, and with strangeness production. The main results of our observations are: (a) a higher (up to 20 times) strangeness production in 4He than in H; (b) the evidence of a possible signature of a $\overline{K}pp$ ( $\overline{K} ppn$ ) bound state; (c) a measurement of a double strangeness production (2K +) and a hint for some production yields of double-strange bound systems like 2K −2n; (d) a signal compatible with the baryonic $\Theta^+(1530)$ resonance, interpreted as a pentaquark system.

Published
2008
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19. Measurement of the proton spectra from non-mesonic weak decay of 5ΛHe, 7ΛLi and 12ΛC

Author

E. M. Fiore, Haruhiko Outa, Paolo Montagna, D. Nakajima, A. Andronenkov, G. Simonetti, F. Pompili, V. Tereshchenko, Paolo Camerini, Elena Botta, D. Calvo, H. C. Bhang, M. Palomba, G. D'Erasmo, A. Filippi, Rinaldo Rui, S. Marcello, A. Feliciello, G. A. Beer, O. Morra, F. De Mori, S. Piano, V. Lucherini, B. Dalena, E. Pace, M. Bertani, Marco Bregant, O. Hartmann, Tomofumi Nagae, D. Faso, Michelangelo Agnello, Adriano Fontana, Y. Lee, Michele Arturo Caponero, Stefania Bufalino, Tullio Bressani, F. L. Fabbri, A. Pantaleo, Aldo Zenoni, Tomofumi Maruta, Paola Gianotti, Hiroyuki Fujioka, A. Panzarasa, N. Mirfakhrai, L. Busso, B. H. Kang, Luigi Benussi, V. Lenti, V. Paticchio, R. Wheadon, N. Grion, Akihisa Toyoda, Stefano Bianco, D. Elia, Michiko Sekimoto, Alexey Krasnoperov, Germano Bonomi, and V. Manzari

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, State (functional analysis), Lower limit, Spectral line, law.invention, Nuclear physics, Low energy, law, Physics::Accelerator Physics, Proton spectra, Atomic physics, Nuclear Experiment, Collider
Abstract

The results of a measurement of the proton spectra following the non-mesonic weak decay of 5ΛHe, 7ΛLi and 12ΛC are presented and discussed. The experiment was performed at the ( e + e − ) collider DAΦNE at Laboratori Nazionale di Frascati of INFN. It is the first measurement for 7ΛLi, and for all the spectra the lower limit on the energy of the protons is 15 MeV, never reached before. All the spectra show a similar shape, namely a peak at around 80 MeV as expected for the free Λ p → n p weak reaction, with a low energy rise that should be due to final state interactions and/or two-nucleon induced weak processes. The decay spectrum of 5ΛHe is somehow similar to the ones reported by previous measurements and theoretical calculations, but the same does not happen for the 12ΛC one.

Published
2008

20. On the use of the (π−,K0) reaction on nuclear targets for the precise determination of the lifetime of the hydrogen hyperisotopes and other neutron-rich Λ-hypernuclei

Author

Michelangelo Agnello, Elena Botta, A. Feliciello, Tullio Bressani, and Stefania Bufalino

Subjects
Nuclear and High Energy Physics, Hydrogen, 3/LAMBDA-H, H-4(LAMBDA), chemistry.chemical_element, Hydrogen hyperisotopes, HE-4(LAMBDA), 01 natural sciences, Spectral line, Ion, Nuclear physics, WEAK DECAY WIDTHS, Partial Weak Decay widths, SHELL HYPERNUCLEI, 0103 physical sciences, Neutron, LIGHT HYPERFRAGMENTS, 010306 general physics, Spectroscopy, Physics, Mass number, SPECTROSCOPY, Lifetime, Lambda-hypernuclei, 010308 nuclear & particles physics, Hyperon, Nuclear structure, PERFORMANCE, chemistry, PI-MESONIC DECAY, H-3(LAMBDA), Atomic physics
Abstract

Recent results reported by experiments with relativistic (heavy) ions have raised again the question whether the lifetime of H Λ 3 is very close to the lifetime of the free Λ hyperon. An updated careful analysis of all the existing experimental data shows that it is not, contrary to theoretical calculations. A similar conclusion can be drawn for the neighbor H Λ 4 . A clear cut high precision measurement performed with the straightforward method of time delay spectra is however lacking and it is eagerly needed. The idea of using the ( π − , K 0 ) charge-exchange associated production reaction on targets of liquid 3,4 He is discussed. A possible realization exploiting a large part of existing facilities at J-PARC is presented. A measurement with a 5% precision seems within reach with a modest effort and in a reasonable amount of time. The same set-up would also serve very well for the measurement of the lifetime of several neutron-rich Λ-hypernuclei of the p -shell, in particular of B Λ 12 . More importantly, the Weak Decay partial widths Γ π − , Γ p and Γ π 0 could be simultaneously determined in order to confirm their predicted strong variation with mass number, A, due to nuclear structure effects.

Published
2016

21. strangeness production in annihilations at rest

Author

Tullio Bressani, A. Panzarasa, Paola Salvini, G. Bendiscioli, and L. Lavezzi

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Antiproton, Analytical chemistry, Strangeness production, Atomic physics, Nucleon
Abstract

Events with production of two K + are observed in p ¯ He 4 annihilations at rest. They are detected in annihilation reactions with four and five prongs and are interpreted to proceed via the following intermediate states: 2 K + Σ − Σ − p s → 2 K + 2 π − ( 2 n p s ) , 2 K + Σ − Σ + n π − → 2 K + π + 2 π − ( 3 n ) , 2 K + Σ − Λ n → 2 K + p 2 π − ( 2 n ) and 2 K + K − Λ 2 n → 2 K + K − p π − ( 2 n ) with yields (lower limits) ( 0.17 ± 0.04 ) × 10 −4 , ( 2.71 ± 0.47 ) × 10 −4 , ( 1.21 ± 0.29 ) × 10 −4 and ( 0.28 ± 0.14 ) × 10 −4 , respectively. They could be the signature of different production mechanisms like rescattering cascades and formation of quark–gluon plasma and of bound K − K − -few nucleon systems. Even though the statistics is very small, signatures compatible with ( K − K − n n ) and ( K − K − n n p ) bound systems are discussed.

Published
2007
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22. Correlated Λd pairs from the Kstop−A→ΛdA′ reaction

Author

H. So, V. Paticchio, Sandro Tomassini, Alessandro Feliciello, D. Di Santo, F. Pompili, R. Wheadon, Paolo Camerini, Michelangelo Agnello, A. Panzarasa, Elena Botta, H. C. Bhang, L. Busso, Tomofumi Nagae, Germano Bonomi, N. Grion, G. Simonetti, F. L. Fabbri, M. Pallotta, V. Lenti, V. Lucherini, V. Manzari, A. Olin, D. Faso, V. Filippini, M. E. Fiore, F. De Mori, P. Cerello, O. Morra, D. Calvo, A. Pantaleo, M. Caponero, Aldo Zenoni, G. D'Erasmo, Akihisa Toyoda, Tomofumi Maruta, Haruhiko Outa, Rinaldo Rui, S. Marcello, Tullio Bressani, L. Benussi, R. Fini, M. Palomba, E. Pace, M. Bertani, Hiroyuki Fujioka, S. Piano, Stefania Bufalino, N. Mirfakhrai, A. Krasnoperov, A. Filippi, R. Donà, V. Tereshchenko, Paola Gianotti, Marco Bregant, B. Dalena, G. A. Beer, O. Hartmann, Stefano Bianco, and D. Elia

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, chemistry, Deuterium, Yield (chemistry), Binding energy, chemistry.chemical_element, Lithium, Invariant mass, Atomic physics, Few-body systems, Absorption (electromagnetic radiation)
Abstract

Correlated Λd pairs emitted after the absorption of negative kaons at rest K stop − A → Λ d A ′ in light nuclei 6Li and 12C are studied. Λ-hyperons and deuterons are found to be preferentially emitted in opposite directions. The Λd invariant mass spectrum of 6Li shows a bump whose mass is 3251 ± 6 MeV / c 2 . The bump mass (binding energy), width and yield are reported. The appearance of a bump is discussed in the realm of the [ K ¯ 3 N ] clustering process in nuclei. The experiment was performed with the FINUDA spectrometer at DAΦNE (LNF).

Published
2007
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23. Feature Article: Hunting the Kaonic Nuclear Clusters

Author

Tullio Bressani

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Neutron star, Particle physics, Feature (computer vision), Nuclear Theory, Hadron, Bound state, Nuclear Experiment, Nucleon, Nuclear matter
Abstract

One of the more controversial recent issues in Hadronic Physics is the possible existence of the so-called Kaonic Nuclear Clusters (KNC), often referred to also as Deeply Bound Kaon States (DBKS). They are strange (S = −1, −2) systems composed by nucleons strongly bound to one or two . This topic is connected with the possible existence of unusual nucleon bound states like pp or ppp, with the possibility that a high-density nuclear medium will be created around the K, that could be a seed for the understanding of the dense nuclear matter in the neutron stars.

Published
2007
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24. Study of the proton weak decay of 12 ΛCg.s. with FINUDA

Author

A. Feliciello, V. Lucherini, Michelangelo Agnello, E. M. Fiore, O. Hartmann, Stefano Bianco, D. Elia, Rinaldo Rui, S. Marcello, Tullio Bressani, A. Pantaleo, Paola Gianotti, N. Mirfakhrai, Paolo Camerini, D. Calvo, M. Pallotta, Sandro Tomassini, R. Wheadon, Stefano Piano, G. Simonetti, O. Morra, N. Grion, Germano Bonomi, G. D'Erasmo, F. Pompili, V. Manzari, B. Dalena, Elena Botta, V. Tereshchenko, G. A. Beer, F. De Mori, A. Panzarasa, L. Busso, H. C. Bhang, F. L. Fabbri, Stefania Bufalino, D. Di Santo, V. Lenti, V. Paticchio, D. Faso, Tomofumi Nagae, E. Pace, M. Bertani, Haruhiko Outa, Hiroyuki Fujioka, Alexey Krasnoperov, Marco Bregant, H. So, Luigi Benussi, P. Cerello, A. Filippi, Akihiro Toyoda, R. Fini, M. Palomba, Michele Arturo Caponero, V. Filippini, Aldo Zenoni, and Tomofumi Maruta

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Proton, Nuclear Theory, Hadron, law.invention, Nuclear physics, law, Physics::Accelerator Physics, Nuclear fusion, Proton spectra, High Energy Physics::Experiment, Nuclear Experiment, Collider
Abstract

The FINUDA experiment studies the Λ-hypernuclei formation and decay using the reaction (K stop − , π−) induced by the low-momentum K − from the deacy of the φ-meson produced at the (e +, e−) collider DAφNE at the Laboratory Nazionali di Frascati of INFN. In this paper we present new data on the proton spectra following the weak decay of Λ 12 C.

Published
2007
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25. Search for signals of bound nuclear states in antiproton-4He annihilations at rest

Author

Alberto Rotondi, Tullio Bressani, A. Panzarasa, G. Bendiscioli, Adriano Fontana, and L. Lavezzi

Subjects
Physics, Rest (physics), Nuclear and High Energy Physics, Large Hadron Collider, Spectrometer, measured bound antikaon nuclear states, Binding energy, antiproton-He-4 annihilation, Nuclear physics, Antiproton, Bound state, Physics::Accelerator Physics, High Energy Physics::Experiment, Invariant mass, Atomic physics, Nuclear Experiment
Abstract

Λp and Λd narrow peaks in the p π − p and p π − d invariant mass distributions are observed in antiproton- 4 He annihilations at rest. By considering the Λp peak as the signature of the two-body decay of the K ¯ p p bound state, its mass, binding energy and decay width would be 2212.1 ± 4.9 MeV , − 160.9 ± 4.9 MeV and 24.4 ± 8.0 MeV with a statistical significance of 3.7 σ . By considering the Λd peak as the signature of the two-body decay of the K ¯ p p n bound state, the same quantities should be 3190 ± 15 MeV , − 121 ± 15 MeV and 60 MeV with a statistical significance of 2.6 σ . Alternative explanations are also discussed. The data were collected with the OBELIX spectrometer at the LEAR complex at CERN.

Published
2007
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26. Σ−pemission rates inK−absorptions at rest onLi6,Li7,Be9,C13, andO16

Author

F. De Mori, Tullio Bressani, M. Bertani, Tomofumi Nagae, D. Calvo, H. Fujioka, Paolo Camerini, Haruhiko Outa, E. M. Fiore, P. Gianotti, V. Paticchio, Germano Bonomi, B. Dalena, Aldo Zenoni, Luisa Benussi, V. Lucherini, Michelangelo Agnello, Marco Bregant, Richard Wheadon, Giuseppe Simonetti, A. Filippi, Andrea Fontana, O. Morra, A. Pantaleo, Stefania Bufalino, P. Genova, G. D'Erasmo, N. Grion, Stefano Piano, Rinaldo Rui, S. Marcello, A. Feliciello, Elena Botta, and L. Busso

Subjects
Physics, Nuclear and High Energy Physics, Physics::Medical Physics, Atomic physics, Nuclear Experiment, Spectral line
Abstract

An experimental study of the ${K}_{\mathrm{stop}}^{\ensuremath{-}}A\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{\ensuremath{-}}p{A}^{\ensuremath{'}}$ reaction on $A=^{6}\mathrm{Li},\phantom{\rule{0.16em}{0ex}}^{7}\mathrm{Li},\phantom{\rule{0.16em}{0ex}}^{9}\mathrm{Be},\phantom{\rule{0.16em}{0ex}}^{13}\mathrm{C}$, and $^{16}\mathrm{O}\phantom{\rule{4pt}{0ex}}p$-shell nuclei is presented. The data were collected by the FINUDA spectrometer operating at the $\mathrm{DA}\mathrm{\ensuremath{\Phi}}\mathrm{NE}\phantom{\rule{4pt}{0ex}}\ensuremath{\phi}$ factory (LNF-INFN, Italy). Emission rates for the reaction in the mentioned nuclei are measured and compared with the few existing data. The spectra of several observables are discussed; indications of quasifree absorptions by a $(np)$ pair embedded in the $A$ nucleus can be obtained from the study of the missing mass distributions.

Published
2015
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27. Search for the pentaquark in antiproton 4He annihilation at rest

Author

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

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

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

Published
2006
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28. Search for HΛ6 and HΛ7 with the (Kstop−,π+) reaction

Author

F. De Mori, H. So, V. Filippini, A. Feliciello, Stefano Bianco, F. L. Fabbri, E. Pace, D. Elia, M. Bertani, Sandro Tomassini, Haruhiko Outa, L. Benussi, A. Olin, Aldo Zenoni, Tomofumi Maruta, Paolo Camerini, V. Tereshchenko, G. A. Beer, R. Don, M. E. Fiore, Akihisa Toyoda, Michelangelo Agnello, A. Filippi, Rinaldo Rui, V. Lenti, S. Marcello, O. Morra, R. Wheadon, N. Grion, G. Simonetti, Paola Gianotti, V. Manzari, D. Calvo, Tomofumi Nagae, A. Pantaleo, D. Faso, V. Paticchio, Marco Bregant, Tullio Bressani, S. Piano, M. Caponero, Elena Botta, F. Pompili, G. D'Erasmo, P. Cerello, H. C. Bhang, N. Mirfakhrai, D. Di Santo, B. Dalena, A. Panzarasa, V. Lucherini, L. Busso, Hiroyuki Fujioka, M. Pallotta, Alexey Krasnoperov, R. Fini, and M. Palomba

Subjects
Nuclear physics, Momentum, Physics, Nuclear and High Energy Physics, Spectrometer, Pi, Analytical chemistry, Neutron, Lambda, Spectral line
Abstract

The production of neutron rich Λ-hypernuclei via the ( K stop − , π + ) reaction has been studied using data collected with the FINUDA spectrometer at the DAΦNE ϕ-factory (LNF). The analysis of the inclusive π + momentum spectra is presented and an upper limit for the production of H Λ 6 and H Λ 7 from 6Li and 7Li, is assessed for the first time.

Published
2006
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29. First results on 12ΛC production at DAΦNE

Author

Paolo Camerini, M. E. Fiore, E. Pace, M. Bertani, V. Filippini, V. Tereshchenko, D. Calvo, H. So, G. D'Erasmo, G. Simonetti, A. Olin, Akihisa Toyoda, Piergiorgio Cerello, F. Pompili, M. Caponero, V. Manzari, D. Di Santo, F.L. Fabbri, G. A. Beer, Sandro Tomassini, A. Panzarasa, Michelangelo Agnello, Marco Bregant, Stefano Bianco, L. Busso, T. Maruta, D. Elia, Hiroyuki Fujioka, M. Pallotta, V. Lucherini, Tomofumi Nagae, R. Donà, F. De Mori, V. Paticchio, Alessandro Feliciello, Alexey Krasnoperov, L. Benussi, B. Dalena, H. Outa, R. Wheadon, D. Faso, Rinaldo Rui, S. Marcello, N. Grion, S. Piano, A. Pantaleo, Elena Botta, H. C. Bhang, O. Morra, V. Lenti, Tullio Bressani, Paola Gianotti, A. Filippi, N. Mirfakhrai, Aldo Zenoni, R. Fini, and M. Palomba

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Spectrometer, Hadron, Lambda, law.invention, Nuclear physics, Momentum, Full width at half maximum, law, Excited state, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, Collider, Ground state
Abstract

A-hypenuclei are produced and studied, with the FINUDA spectrometer, for the first time at an e(+)e(-) collider: DA Phi NE, the Frascati phi-factory. The slow negative kaons from phi(1020) decay are stopped in thin (0.2 g/cm(2)) nuclear targets, and A-hypemuclei formation is detected by measuring the momentum of the outgoing pi(-). A preliminary analysis on C-12(Lambda) shows X an energy resolution of 1.29 MeV FWHM on the hypernuclear levels, the best obtained so far with magnetic spectrometers at hadron facilities. Capture rates for the ground state and the excited ones are reported, and compared with previous experiments. (c) 2005 Elsevier B.V. All rights reserved

Published
2005
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30. First hypernuclear results from the FINUDA experiment at DAΦNE

Author

F. De Mori, Paolo Camerini, E. Pace, M. Bertani, F. L. Fabbri, V. Filippini, D. Calvo, H. So, G. D'Erasmo, G. Simonetti, O. Morra, A. Olin, Luigi Benussi, P. Cerello, F. Pompili, D. Di Santo, V. Lucherini, G. A. Beer, Sandro Tomassini, A. Panzarasa, Michelangelo Agnello, Stefano Bianco, L. Busso, T. Maruta, Hiroyuki Fujioka, M. Pallotta, P. Gianotti, A. Filippi, E. M. Fiore, Richard Wheadon, V. Paticchio, B. Dalena, A. Feliciello, D. Faso, Rinaldo Rui, S. Marcello, N. Grion, S. Piano, A. Pantaleo, Elena Botta, Tullio Bressani, N. Mirfakhrai, Aldo Zenoni, M. Palomba, A. Krasnoperov, M., Bertani, M., Agnello, G., Beer, L., Benussi, S., Bianco, E., Botta, T., Bressani, L., Busso, D., Calvo, Camerini, Paolo, P., Cerello, B., Dalena, F., DE MORI, G., D'Erasmo, D., DI SANTO, F. L., Fabbri, D., Faso, A., Feliciello, A., Filippi, V., Filippini, E. M., Fiore, H., Fujioka, P., Gianotti, N., Grion, A., Krasnoperov, V., Lucherini, S., Marcello, T., Maruta, N., Mirfakhrai, O., Morra, A., Olin, E., Pace, M., Pallotta, M., Palomba, A., Pantaleo, A., Panzarasa, V., Paticchio, S., Piano, F., Pompili, Rui, Rinaldo, G., Simonetti, H., So, S., Tomassini, R., Wheadon, and A., Zenoni

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Spectrometer, Meson, Astronomy and Astrophysics, Strangeness, Hypernucleus, Spectroscopy, Atomic and Molecular Physics, and Optics
Abstract

FINUDA is the hypernuclear physics experiment carried out at DAΦNE, the e+e- ϕ-factory of the INFN Frascati Laboratory. The aim of the experiment is to study simultaneously the formation and decay of hypernuclei produced by the strangeness exchange reaction induced by the stopped K- coming from the decay of the ϕ(1020) mesons. This paper presents the first preliminary results concerning spectrometer performances, hypernuclear formation and decay from the first FINUDA data set.

Published
2005
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31. Production and decay of $\eta^{\prime}(958)$ and $\eta (1440)$ in $\bar p p$ annihilation at rest

Author

M. Corradini, F. Nichitiu, A.M. Rozhdestvensky, G. Pauli, Paolo Montagna, Paola Salvini, M. Lombardi, Massimo Piccinini, El Rizzini, Roberto Spighi, F. Tosello, Ableev, A. Vitale, S. Decastro, O.E. Gorchakov, D. Galli, A M Rosca, C. Guaraldo, Lucherini, M.G. Sapozhnikov, Alberto Masoni, G. Maron, D. Calvo, L. Santi, O. Y. Denisov, Bruno Minetti, Antonietta Donzella, Felice Iazzi, Armando Lanaro, L. Fava, G. Bendiscioli, Umberto Marini Bettolo Marconi, C. Scoglio, F. Balestra, Nicola Semprini-Cesari, L. Busso, Filippini, C. Cicalo, A. Grasso, E. Rossetto, M. Capponi, M. Poli, Mauro Villa, L. Ferrero, G. Vedovato, L. Vannucci, P. Gianotti, S. Serci, S. Tessaro, Benedetto Giacobbe, Alberto Rotondi, A. Collamati, Tullio Bressani, F. Vigotti, C. Petrascu, D. Panzieri, U. Gastaldi, D. Parena, C. Cavion, Aldo Zenoni, G. Puddu, R. Garfagnini, S. Costa, Elena Botta, Michelangelo Agnello, S.N. Prakhov, Antonio Zoccoli, P. Cerello, A. Bertin, A. Lai, L. Musa, Antonio Ferretti, A. Filippi, R. Donà, A. Feliciello, Andrea Fontana, Mp Bussa, V.I. Tretyak, A. Maggiora, A. Saino, Stefania Vecchi, Marco Bruschi, L. Valacca, L. Venturelli, P.P. Temnikov, A. Vezzani, G. L. Usai, and S. Marcello

Subjects
Quantum chromodynamics, Rest (physics), Physics, Particle physics, Physics and Astronomy (miscellaneous), Glueball, Partial wave analysis, Pi, State (functional analysis), Engineering (miscellaneous), Pseudovector
Published
2004
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32. First Experimental Determination of the One-Proton Induced Non-Mesonic Weak Decay Width forp-shell Λ-hypernuclei

Author

Tomofumi Nagae, V. Lucherini, Michelangelo Agnello, Rinaldo Rui, S. Marcello, B. Dalena, Stefano Piano, Germano Bonomi, Aldo Zenoni, Elena Botta, D. Calvo, H. C. Bhang, A. Filippi, A. Feliciello, N. Grion, Haruhiko Outa, Giuseppe Simonetti, Tullio Bressani, Luisa Benussi, F. De Mori, M. Bertani, H. Fujioka, Paolo Camerini, P. Gianotti, V. Paticchio, Stefania Bufalino, and G. D'Erasmo

Subjects
Nuclear physics, Physics, DAΦNE, non-mesonic weak decay, Proton, p-shell Λ-hypernuclei, Shell (structure), DAΦNE, FINUDA experiment, p-shell Λ-hypernuclei, non-mesonic weak decay, Atomic physics, FINUDA experiment
Published
2015

33. 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
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34. Search for a narrow state at 1.9 GeV in 3π+2π−π0 exclusive events in p annihilation

Author

S. Marcello, A. Filippi, M. Astrua, Tullio Bressani, Elena Botta, D. Calvo, A. Feliciello, Felice Iazzi, and Michelangelo Agnello

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Narrow state, Resonance formation, State (functional analysis), n̄p annihilation at low energy
Abstract

No evidence has been found for a narrow state at 1.911 GeV, recently reported by E687, in an analysis of the 3 π + 2 π − π 0 exclusive events produced in n p annihilations in flight.

Published
2002
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35. Antineutron–nucleus annihilation cross sections below 400 MeV/c

Author

Felice Iazzi, D. Calvo, Elena Botta, Michelangelo Agnello, A. Filippi, S. Marcello, A. Feliciello, Tullio Bressani, M. Astrua, and C. Casalegno

Subjects
Physics, Momentum, Nuclear reaction, Nuclear physics, Mass number, Nuclear and High Energy Physics, Range (particle radiation), Cross section (physics), Annihilation, Atomic physics, Antineutron, Nucleon
Abstract

Antineutron annihilation cross sections on C, Al, Cu, Ag, Sn and Pb targets were measured in the momentum range 50–400 MeV/c. The full set of data is very well described by a parameterization in which the target mass number and momentum dependence are factorized. The A dependence is, within 2%, consistent with a A2/3 scaling law, indicating a pure surface process. The momentum dependence is, within 20%, consistent with that expected from a properly averaged contribution of the elementary cross section for n p and n n annihilation, indicating that the process is due to the interaction with single nucleons on the surface.

Published
2002
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36. 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
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37. The latest results from OBELIX

Author

Tullio Bressani

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Nuclear Theory, Hadron, Strangeness, Quarkonium, Pseudoscalar, Nuclear physics, Anomaly (physics), Nuclear Experiment, Nucleon
Abstract

The most recent achievements of the analysis of the data collected by the OBELIX experiment at LEAR are presented. The most interesting results concern the apparent OZI-rule violation in some annihilation channels and the consequent explanation in terms of a polarized ( s s ) strangeness content of the nucleon, a further convincing evidence for the presence of two pseudoscalar states in the E ι region and finally the observation of a tantalizing anomaly in the total antineutron-proton cross section at very low momenta.

Published
2000
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38. Study of η and η′ production in annihilations

Author

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

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, P wave, Pseudoscalar meson, Nuclear physics, Pseudoscalar, Production (computer science), Mixing (physics), Line (formation)
Abstract

The annihilation fractions and cross sections for the n p annihilation reaction in flight (∼50–400 MeV/c) into ηπ+ and η′π+ final states have been measured. The first ones follow the trend expected for P wave annihilations. From the ratios of the yields an evaluation of the pseudoscalar mixing angle in the standard form is possible. The value found shows that for pseudoscalar meson production from P wave the Quark Line Rule is not grossly violated.

Published
1999
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39. and annihilation cross sections at very low energy

Author

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

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

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

Published
1999
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40. Evidence for two pseudoscalar states in the 1.4–1.5 GeV mass region

Author

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

Subjects
Pseudoscalar, Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics
Abstract

A confirming evidence for two pseudoscalar states with masses M 1 =1405±5, Γ 1 =50±4 MeV/ c 2 and M 2 =1500±10, Γ 2 =100±20 MeV/ c 2 is reported. The second pseudoscalar fills the nonet and leaves the first as an outsider supporting the hypothesis for its exotic nature.

Published
1999
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41. 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
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42. Light baryon production in binary annihilation reactions at rest

Author

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

Subjects
Baryon, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Deuterium, Antiproton, Binary number
Abstract

We report the study of light baryon production in two-prong annihilation reactions due to antiprotons stopping in gaseous deuterium and detected by the OBELIX spectrometer (LEAR, CERN). A clear signal of the Δ(1232) production in binary reactions was found in both annihilation channels: p d→π − Δ + (Δ + →π 0 p) and p d→π 0 Δ 0 (Δ 0 →π − p) . The annihilation probabilities for these reactions turned out to be Y=(1.01±0.08)×10−5 and Y=(1.12±0.20)×10−5, respectively. In addition, the annihilation probability for the prototype Pontecorvo reaction p d→π − p was measured with the best world statistics: Y=(1.46±0.08)×10−5.

Published
1999
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43. The FINUDA superconducting magnet at DAΦNE

Author

A. Lanaro, V. Lucherini, F.L. Fabbri, A. Feliciello, B. Dulach, M. Bertani, A. Cecchetti, M. Giardoni, Tullio Bressani, A. Filippi, and Aldo Zenoni

Subjects
Physics, Cryostat, Nuclear and High Energy Physics, Electromagnet, Physics::Instrumentation and Detectors, Solenoid, Superconducting magnet, Atomic and Molecular Physics, and Optics, Particle detector, law.invention, Nuclear physics, law, Electromagnetic coil, Magnet, Physics::Accelerator Physics, High Energy Physics::Experiment, Collider
Abstract

FINUDA is an experiment aiming at high resolution hypernuclear spectroscopy. It employs different types of detectors enclosed inside a large superconducting solenoid. It will operate on the new, high luminosity (e+ − e−) collider DAΦNE of the INFN Frascati National Laboratory. The solenoid operates at 2765 A maximum current corresponding to a magnetic field of 1.1 T. The inner dimensions are: 2.4 m length, 2.7 m diameter. The coil within its cryostat is enclosed inside an iron return yoke composed by a central barrel and two end-caps which can be opened to access the inner detectors. The magnetic field in the inner volume has been fully mapped for both main and minor components. The alignment of such a magnet on a machine as DAΦNE is a very crucial item, needing particular care.

Published
1999
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44. Study of φ and f′2(1525) meson production in annihilation at rest

Author

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

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, OZI rule, Branching fraction, Antiproton, Yield (chemistry), Mass spectrum, Dalitz plot, Quantum number
Abstract

The reaction p p→K + K − π 0 was analysed for antiproton annihilations at rest at three hydrogen target densities. A strong dependence of the p p→φπ 0 yield on the quantum numbers of the initial state is observed. The branching ratio of the φπ0 channel from the 3S1 initial state is more than 15 times larger than the one from the 1P1 state. A large apparent violation of the OZI rule for tensor meson production from p p -annihilations from the P-waves (1+++2++) is observed: Rexp(f′2π0/f2π0)=(149±20)·10−3, significantly exceeding the OZI-rule prediction R=16·10−3.

Published
1998
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45. Study of the isovector scalar mesons in the channel p̄p→K±K0Sπ∓ at rest with initial angular momentum state selection

Author

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

Subjects
Hydrogen density, Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Angular momentum, Isovector, Meson, Scalar (physics)
Abstract

The study of the I =1, J PC =0 ++ states with the OBELIX detector in the channel p p→K ± K 0 S π ∓ at three different target densities is reported. The data show the evidence for an extra scalar state with mass 1.29±0.01 GeV/ c 2 and width 0.080±0.005 GeV/ c 2 .

Published
1998
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46. Study of thef0(1500)/f2(1565)production in the exclusive annihilationn̄p→π+π+π−in flight

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Pi, Invariant mass, Production (computer science)
Abstract

The spin-parity analysis of the $\mathrm{n\ifmmode \bar{}\else \={}\fi{}}\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ exclusive reaction in flight is presented. The main aim is to study the $({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$ invariant mass spectrum in the region around 1500 MeV. The analysis was performed with a Breit-Wigner parametrization for all the resonant states and, for the scalar sector in the mass region below 1.2 GeV, by means of a K-matrix-like treatment. It clearly shows the need for two states, a scalar one ${(0}^{++})$ with mass and width $(1522\ifmmode\pm\else\textpm\fi{}25) \mathrm{MeV}$ and $(108\ifmmode\pm\else\textpm\fi{}33) \mathrm{MeV}$, and a tensorial one ${(2}^{++})$ with mass $(1575\ifmmode\pm\else\textpm\fi{}18) \mathrm{MeV}$ and width $(119\ifmmode\pm\else\textpm\fi{}24) \mathrm{MeV}$, respectively. In addition, the analysis requires the presence of a scalar state at $(1280\ifmmode\pm\else\textpm\fi{}55) \mathrm{MeV}$, $(323\ifmmode\pm\else\textpm\fi{}13) \mathrm{MeV}$ broad, and of a second vectorial one, in addition to the ${\ensuremath{\rho}}^{0}(770)$ signal, with mass and width $(1348\ifmmode\pm\else\textpm\fi{}33) \mathrm{MeV}$ and $(275\ifmmode\pm\else\textpm\fi{}10) \mathrm{MeV}$, respectively.

Published
1998
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47. First determination of the one-proton induced Non-Mesonic Weak Decay width of p-shell Λ-Hypernuclei

Author

Haruhiko Outa, V. Lucherini, G. D'Erasmo, Michelangelo Agnello, Stefania Bufalino, N. Grion, A. Filippi, M. Bertani, Luisa Benussi, D. Calvo, H. Fujioka, Paolo Camerini, Germano Bonomi, B. Dalena, Tullio Bressani, Tomofumi Nagae, Aldo Zenoni, F. De Mori, P. Gianotti, A. Feliciello, V. Paticchio, Rinaldo Rui, S. Marcello, Stefano Piano, Elena Botta, G. Simonetti, H. C. Bhang, M., Agnello, L., Benussi, M., Bertani, H. C., Bhang, G., Bonomi, E., Botta, T., Bressani, S., Bufalino, D., Calvo, Camerini, Paolo, B., Dalena, F., De Mori, G., D'Erasmo, A., Feliciello, A., Filippi, H., Fujioka, P., Gianotti, N., Grion, V., Lucherini, S., Marcello, T., Nagae, H., Outa, V., Paticchio, Piano, Stefano, Rui, Rinaldo, G., Simonetti, and A., Zenoni

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Proton, Shell (structure), Non-Mesonic Weak Decaywidth, Neutron spectra, one-proton induced, Non-mesonic decay of hypernuclei, Λ-Hypernuclei, Spectral line, Coincidence, Nuclear physics, Two-nucleon and proton-induced, Neutron, Nuclear Experiment, Physics, FINUDA, Lambda-Hypernuclei, lcsh:QC1-999, Cascade, Two-nucleon and proton-induced Non-Mesonic Weak Decay width, Proton spectra, High Energy Physics::Experiment, Atomic physics, lcsh:Physics
Abstract

Previous studies of proton and neutron spectra from Non-Mesonic Weak Decay of eight Lambda-Hypernuclei (A = 5-16) have been revisited. New values of the ratio of the two-nucleon and the one-proton induced decay widths, Gamma_2N/Gamma_p, are obtained from single proton spectra, Gamma_2N/Gamma_p = 0.50 +/- 0.24, and from neutron and proton coincidence spectra, Gamma_2N/Gamma_p = 0.36 +/- 0.14stat +0.05sys -0.04sys , in full agreement with previously published ones. With these values, a method is developed to extract the one-proton induced decay width in units of the free Lambda decay width, Gamma_p/Gamma_Lambda, without resorting to Intra Nuclear Cascade models but by exploiting only experimental data, under the assumption of a linear dependence on A of the Final State Interaction contribution. This is the first systematic determination ever done and it agrees within the errors with recent theoretical calculations., Comment: 16 pages, 3 figures, 2 tables

Published
2014

48. Study of the annihilation from S states

Author

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

Subjects
Momentum, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Pion, Annihilation, Meson, State (functional analysis)
Abstract

The results of the spin-parity analysis of annihilations at very low momentum (≈ 50 MeV/c) are reported. To describe the data the production of the ϱ, f2, a2 and a1 mesons and the presence of the ππ interaction in S-wave (the σ term) in the final state are necessary. The best fit solution requires also the presence of a ϱ′ state of mass and width M = 1.282 ± 0.037, Γ = 0.236 ± 0.036 GeV/c2 and of a heavy pion π(1300) of mass and width M = 1.275 ± 0.015, Γ = 0.218 ± 0.100 GeV/c2. The measured fraction of the annihilation cross section into 2π+2π− is (7.61 ± 0.35) · 10−2.

Published
1997
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49. Study of annihilation in two mesons in the momentum range between 50 to 400 MeV/c with OBELIX

Author

P.P. Temnikov, Antonietta Donzella, Paolo Montagna, Stefania Vecchi, S. Costa, Elena Botta, L. Fava, Adriano Fontana, A.M. Rozhdestvensky, M.G. Sapozhnikov, I. Massa, R. Garfagnini, M. Corradini, S. Marcello, Marco Bruschi, Alberto Masoni, Paola Salvini, S.N. Prakhov, G. Pauli, L. Ferrero, Massimo Piccinini, F. Vigotti, D. Calvo, A. Vezzani, Bruno Minetti, Antonio Ferretti, L. Valacca, V.G. Ableev, S. Decastro, Alberto Rotondi, L. Venturelli, S. Serci, C. Petrascu, F. Nichitiu, L. Busso, O.E. Gorchakov, D. Parena, M. Poli, G. Vedovato, Tullio Bressani, F. Tosello, A. Saino, A M Rosca, Maria Pia Bussa, U. Gastaldi, S. Tessaro, V.I. Tretyak, G. L. Usai, G. Maron, O. Y. Denisov, A. Maggiora, Paola Gianotti, M. Lombardi, A. Collamati, Mauro Villa, V. Lucherini, M. Capponi, L. Vannucci, D. Galli, V. Filippini, G. Puddu, V. Vagnoni, L. Santi, Felice Iazzi, Armando Lanaro, C. Cavion, Roberto Spighi, Corrado Cicalo, Aldo Zenoni, Nicola Semprini-Cesari, D. Panzieri, C. Scoglio, A. Vitale, A. Grasso, Umberto Marini Bettolo Marconi, E. Rossetto, E. L. Rizzini, Alessandro Feliciello, Benedetto Giacobbe, G. Bendiscioli, A. Filippi, R. Donà, C. Guaraldo, A.E. Kudryavtsev, P. Cerello, A. Bertin, Michelangelo Agnello, F. Balestra, L. Filippi, and Antonio Zoccoli

Subjects
Momentum, Physics, Nuclear physics, Nuclear and High Energy Physics, Range (particle radiation), Annihilation, Deuterium, Meson, Atomic physics, Antineutron, Bar (unit)
Abstract

We measured the in flight annihilation frequencies and cross sections of reactions n p → π + π 0 ,π + η and K+KS in the antineutron momentum range between 50 and 400 MeV/c. The annihilation frequencies of these channels from the different allowed initial states were calculated and some information about the n p annihilation dynamics were obtained. The first determination of the D-wave contribution in this momentum range was also obtained.

Published
1997
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50. Spin-parity analysis of the final state π+π−π0 from annihilation at rest in hydrogen targets at three densities

Author

Nicola Semprini-Cesari, Alberto Masoni, Paola Salvini, S. Costa, D. Calvo, V. Vagnoni, M. Poli, G. Vedovato, A. Saino, C. Scoglio, Roberto Spighi, A. Grasso, Mauro Villa, Umberto Marini Bettolo Marconi, Paola Gianotti, M.P. Bussa, A. Vitale, A. Collamati, L. Filippi, Stefania Vecchi, O. Y. Denisov, C. Damiani, L. Ferrero, L. Fava, Michelangelo Agnello, Antonio Ferretti, V. Filippini, I. Massa, O.E. Gorchakov, G. Maron, V.I. Tretyak, C. Cavion, S. De Castro, Aldo Zenoni, A.M. Rozhdestvensky, A M Rosca, D. Galli, A. Maggiora, S. Marcello, M.G. Sapozhnikov, Antonietta Donzella, V. Lucherini, R. Garfagnini, L. Busso, Tullio Bressani, Bruno Minetti, F. Nichitiu, U. Gastaldi, S. Serci, P.P. Temnikov, Alberto Rotondi, L. Valacca, Massimo Piccinini, C. Petrascu, Adriano Fontana, D. Parena, A. Vezzani, L. Venturelli, V.G. Ableev, Paolo Montagna, G. Pauli, F. Vigotti, L. Vannucci, Armando Lanaro, G. Puddu, Elena Botta, E. Rossetto, Marco Bruschi, M. Capponi, R. A. Ricci, G. L. Usai, D. Panzieri, M. Corradini, S.N. Prakhov, F. Tosello, S. Tessaro, P. Cerello, Felice Iazzi, Corrado Cicalo, A. Bertin, A. Filippi, R. Donà, Antonio Zoccoli, F. Balestra, C. Guaraldo, G. Bendiscioli, L. Santi, Alessandro Feliciello, Benedetto Giacobbe, and E. Lodi Rizzini

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Annihilation, Amplitude, Hydrogen, chemistry, Partial wave analysis, Pi, chemistry.chemical_element, Parity (physics), Vector meson, Atomic physics
Abstract

The partial wave analysis of the reaction p p → π + π − π 0 at rest has been performed for the first time by using high-statistics data sets collected in hydrogen targets at three different densities. The different mixtures of partial waves corresponding to our samples allow a reliable determination of each contribution. This technique is crucial in the identification of the exotic candidate f2(1565) which can be produced by 1S0, 3P1 and 3P2 initial states. The amplitude analysis was performed in the frame of the K-Matrix and P-Vector approach. It requires presence of the exotic candidates f0(1500) and f2(1565) with the following masses and total widths: (1449 ± 20)MeV, (114 ± 30)MeV and (1507 ± 15)MeV, (130 ± 20)MeV respectively. In addition to f0(980), f0(1300) f2(1270) and ϱ(770), a clear evidence of I = 1, JP = 1− signal, which we identify with ϱ(1450), is obtained.

Published
1997
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