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15 results on '"O.E. Gorchakov"'

1. On the formation and decay of the atomcule

Author

F. Balestra, C. Petrascu, L. Santi, Antonietta Donzella, Armando Lanaro, M.P. Bussa, Germano Bonomi, C. Guaraldo, O. Y. Denisov, V. Lucherini, A.M. Rozhdestvensky, E. Lodi Rizzini, A. Grasso, M. Maggiora, Gianfranco Zosi, L. Busso, G. Piragino, G. V. Margagliotti, M.L. Colantoni, S.N. Prakhov, R. Vilar, M. Corradini, F. Tosello, S. Tessaro, L. Ferrero, G. Gomez, Andrea Bianconi, P. Gianotti, R. Garfagnini, L. Venturelli, V.I. Tretyak, A. Maggiora, and O.E. Gorchakov

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Microsecond, Large Hadron Collider, Metastability, Atomic physics, Nanosecond, Exotic atom, Bar (unit)
Abstract

Up to now it has been observed that a fraction of about 3% of the p 's stopped in a dense He target survives for a surprisingly long time (tens of microseconds). As suggested by Condo in 1964 the long lifetime of p 's in He is explained by the existence of metastable states of the exotic atom p He + . An analysis of data from p 's stopped in He targets at 3 bar pressure by the Obelix apparatus at the LEAR decelerator at CERN is presented. We do not observe any significative amount of “prompt” annihilations (few nanoseconds) after the p 's capture.

Published
2001
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2. 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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3. 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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4. 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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5. 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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6. 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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7. 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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8. 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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9. 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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10. A search for axial vectors in annihilations at rest in gaseous hydrogen at NTP

Author

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

Subjects
Pseudoscalar, Physics, Nuclear physics, Nuclear and High Energy Physics, Annihilation, Gaseous hydrogen, Pi
Abstract

The study of the K±Kmiss0π∓π+π− channel (7016 events), from p p annihilations in a gaseous hydrogen target at NTP, with the OBELIX spectrometer at LEAR (CERN), is presented. A spin-parity analysis provides evidence for two axial vectors, one in the low K K π mass region, the well established f1(1285), decaying to a0(980)π, the second, the 1++ component of the old puzzling E l , the f1(1420), decaying mainly to K ∗ K , seen for the first time in p p annihilation at rest. The analysis confirms the dominant production of the pseudoscalar η(1405), decaying mainly to (Kπ) S K , and the existence of a second pseudoscalar in the same mass region, the η(1460), decaying mainly to K ∗ K .

Published
1997
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11. Experimental estimation of the lifetime of atoms formed by π+ and π− mesons

Author

L. Afanasyev, A.V. Kuptsov, V.V. Kruglov, A.V. Kulikov, L.L. Nemenov, M.V. Nikitin, Zh.P. Pustylnik, A.V. Kolomyichenko, S.V. Trusov, V.I. Komarov, O.E. Gorchakov, V. Karpukhin, A.S. Chvyrov, and V. Yazkov

Subjects
Physics, Nuclear and High Energy Physics, Meson, State (functional analysis), Atomic physics, Pionium
Abstract

Based on observation [L.G. Afanasyev et al., Phys. Lett. B 308 (1993) 200] of 272±49 atoms formed by π + and π − an estimation of the atom lifetime in the ground (1S) state is obtained: τ 1 = (2.9 +∞ −2.1 ) · 10 −15 s or τ 1 > 0.6·10 −15 s at 90% confidence level. Atoms were produced in inclusive p Ta interactions at 70 GeV.

Published
1994
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12. Observations of atoms consisting of π+ and π− mesons

Author

Mikhail A. Ivanov, V. Yazkov, V. Karpukhin, A.V. Kolomyichenko, A.V. Kuptsov, Zh.P. Pustylnik, S.V. Trusov, A.V. Kulikov, V.V. Kruglov, M.V. Nikitin, O.E. Gorchakov, L.L. Nemenov, L. Afanasyev, V. Komarov, A.P. Kurov, G.G. Mkrtchyan, and A.S. Chvyrov

Subjects
Condensed Matter::Quantum Gases, Physics, Nuclear physics, Nuclear and High Energy Physics, Meson, Nuclear Theory, High Energy Physics::Experiment, Physics::Atomic Physics, Atomic physics, Nuclear Experiment, Pionium
Abstract

In the experiment 272±49 atoms consisting of π + and π + − mesons were observed. The atoms were produced in a Ta target by 70 GeV protons and π + and π − mesons were detected from the atom break-up in the same target.

Published
1993
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13. Measurement of the branching ratio for the π0-meson decay into a photon and a positronium atom

Author

A.V. Kuptsov, S.M. Frolikov, L.L. Nemenov, A.V. Kulikov, K.I. Gubrienko, M.V. Nikitin, M.N. Shumakov, V.I. Kotov, V.I. Komarov, V.V. Kruglov, L. Afanasyev, A.V. Kolomyichenko, A.S. Chvyrov, O.E. Gorchakov, S.V. Trusov, V. Karpukhin, and Zh.P. Pustylnik

Subjects
Momentum, Physics, Nuclear physics, Nuclear and High Energy Physics, Photon, Meson, Branching fraction, Atom, Radiative transfer, High Energy Physics::Experiment, Elementary particle, Atomic physics, Positronium
Abstract

The ratio of the number of ultrarelativistic positronium atoms ( A 2e ) to the photon number in the momentum interval 800–2000 MeV/ c has been measured in pC interactions at E p =70 GeV and at an angle of 8.4° in the laboratory frame. The branching ratio ϱ π =(1.84±0.29)×10 -9 for π 0 decay into a photon and A 2e has been obtained. The parameter ϱ π is determined by the conversion probability ϱ A of a time-like photon into A 2e in radiative decays of elementary particles.

Published
1990
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14. Observation of the Coulomb interaction effect in pion pairs from the reaction p + Ta → π+ + π− + X at 70 GeV

Author

S.V. Trusov, V.V. Kruglov, V.I. Komarov, M.N. Shumakov, A.V. Kulikov, Zh.P. Pustylnik, M.V. Nikitin, A.V. Kolomyichenko, A.P. Kurov, L.L. Nemenov, A.V. Kuptsov, L. Afanasyev, V. Karpukhin, A.S. Chvyrov, S.M. Frolikov, O.E. Gorchakov, Mikhail A. Ivanov, and V. Yazkov

Subjects
Scattering cross-section, Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Function (mathematics), Proton energy, Momentum, Nuclear physics, Nuclear interaction, Pion, Pair production, Coulomb, High Energy Physics::Experiment, Nuclear Experiment
Abstract

Pion pair production from the proton-tantalum nuclear interaction at proton energy 70 GeV has been studied. Pion correlations as a function of the relative momentum in a pair CMS have been measured at the relative momentum region below 40 MeV/ c . The experimental data agree with the calculation that takes into account the Coulomb factor in the differential cross section of pion pairs production.

Published
1991
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15. Measurement of the η(1440) → K±K0π± production rates from p annihilation at rest at three different hydrogen target densities [Phys. Lett. B 385 (1996) 493]

Author

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

Subjects
Rest (physics), Nuclear and High Energy Physics, Annihilation, Hydrogen, Chemistry, chemistry.chemical_element, Production (computer science), Atomic physics
Abstract

Due to a most unfortunate technical mishap, half of the references in the list of references were not printed. Below the full list of references is being reprinted

Published
1997
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