Annihilation cross-sections of antineutrons on C, Al, Cu, Sn and Pb at low momenta (180–280 MeV/c) with the OBELIX spectrometer

Ableev, V.G.; Adamo, A.; Agnello, M.; Balestra, F.; Belli, G.; Bendiscioli, G.; Bertin, A.; Boccaccio, P.; Bonazzola, G.C.; Botta, E.; Bressani, T.; Bruschi, M.; Bussa, M. P.; Busso, L.; Calvo, D.; Capponi, M.; Cereda, B.; Cerello, P.; Cicalò, C.; Corradini, M.; Costa, S.; Castro, S. De; Leo, C. De; Desinov, D. Yu.; D'Isep, F.; Donzella, A.; Fava, L.; Feliciello, A.; Ferrero, L.; Filippi, A.; Filippini, V.; Galli, D.; Garfagnini, R.; Gastaldi, U.; Giacobbe, B.; Gianotti, P.; Grasso, A.; Guaraldo, C.; Iazzi, F.; Lanaro, A.; Rizzini, E. Lodi; Lombardi, M.; Lucherini, V.; Maggiora, A.; Marcello, S.; Marconi, U.; Margagliotti, G. V.; Maron, G.; Masoni, A.; Massa, I.; Minetti, B.; Montagna, P.; Morando, M.; Nichitiu, F.; Panzieri, D.; Parena, D.; Pauli, G.; Piccinini, M.; Piragino, G.; Poli, M.; Prakhov, S.; Puddu, G.; Ricci, R. A.; Rossetto, E.; Rotondi, A.; Rozhdestvensky, A.M.; Salvini, P.; Santi, L.; Sapozhnikov, M. G.; Semprini‐Cesari, N.; Serci, S.; Spighi, R.; Temnikov, P.; Tessaro, S.; Tosello, F.; Tretyak, V.I.; Usai, G. L.; Vannucci, L.; Vecchi, S.; Vedovato, G.; Venturelli, L.; Vitale, A.; Zenoni, A.; Zoccoli, À.; Zosi, G.

doi:10.1007/bf02731106

Cited by 14 publications

(4 citation statements)

References 24 publications

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“…Then-nucleus annihilation data of [14] (see table 2 and fig.7 in that work) cover the range 76-380 MeV/c on several nuclear targets from carbon to lead, and are presently the available data reaching the smallest energy. For p ≥ 128 MeV/c, the data from this experiment confirm very well previous data [13] and are almost perfectly fitted by an a + b/p law, with a relevant contribution of the b/p term. The smallest energy point at 76 MeV/c overrates by 15-20 % this fit, for all the target nuclei, and an additional 1/p 2 term is needed to fit this last point.…”

Section: Antineutron-nucleus and Antiproton-nucleus Annihilation Crossupporting

confidence: 87%

“…The data that are most relevant for the present work are the cross sections of antineutron annihilation on medium and large nuclei for projectile momentum p < 400 MeV/c. These have been measured by several collaborations in the years 1980-2002 [10,11,12,13,14] (see also [15] for a state-of-the-art review). Then-nucleus annihilation data of [14] (see table 2 and fig.7 in that work) cover the range 76-380 MeV/c on several nuclear targets from carbon to lead, and are presently the available data reaching the smallest energy.…”

Section: Antineutron-nucleus and Antiproton-nucleus Annihilation Crosmentioning

confidence: 99%

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Enhancement of annihilation cross sections by electric interactions between the antineutron and the field of a large nucleus

et al. 2014

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Abstract. Data relative to antineutron and antiproton annihilation on large nuclei in the range MeV/c present two unexpected features: (a) antineutron and antiproton cross sections have a similar size, (ii) the rise of the antineutron cross section at decreasing energy is much steeper than predictable for an inelastic process of purely strong nature at that energy. The observed behavior ofn-nucleus annihilations is similar to what would be expected forp-nucleus annihilations, where Coulomb attraction focussesp trajectories towards the nucleus, enhancing the inelastic cross section by a factor O(1/p) with respect ton on the same target. This results in a 1/p 2 behavior at small energies. The presence of a similar enhancement in the antineutron case may only be justified by an interaction with a longer range than strong interactions. Excluding a Coulomb force because of then neutrality, and taking into account that an intrinsic electric dipole is forbidden for the antineutron, the next choice is an electric dipole that is induced by the nuclear electric field. Recent theoretical works have shown that a non-negligible electric polarization may be induced in a neutron by QED vacuum polarization. Assuming this as a possibility, we have used a simple model to calculate the polarization strengths that are needed to fit the available data in terms of this effect. These are within the magnitude predicted by the vacuum polarization model. We have also discussed alternative scenarios that could induce an electric polarization of the antineutron as a consequence of the interplay between strong and e.m. interactions.PACS. 12.20.-m Quantum electrodynamics -24.80.+y Nuclear tests of fundamental interactions and symmetries -25.43.+t Antiproton-induced reactions

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Section: Antineutron-nucleus and Antiproton-nucleus Annihilation Crossupporting

confidence: 87%

Section: Antineutron-nucleus and Antiproton-nucleus Annihilation Crosmentioning

confidence: 99%

Enhancement of annihilation cross sections by electric interactions between the antineutron and the field of a large nucleus

et al. 2014

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“…On the experimental side, one representative investigation is the measurement of then-Fe annihilation cross section from 100 to 780 MeV/c [46][47][48]. The experiment was carried out with the LEAR facility at CERN using thepp →nn charge-exchange reaction.…”

Section: Introductionmentioning

confidence: 99%

Optical model potential analysis of n¯A and nA interactions

Lee

Wong

2018

Phys. Rev. C

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We use a momentum-dependent optical model potential to analyze the annihilation cross sections of the antineutronn on C, Al, Fe, Cu, Ag, Sn, and Pb nuclei for projectile momenta p lab 500 MeV/c. We obtain a good description of annihilation cross section data of Barbina et al. [Nucl. Phys. A 612, 346 (1997)] and of Astrua et al. [Nucl. Phys. A 697, 209 (2002)] which exhibit an interesting dependence of the cross sections on p lab as well as on the target mass number A.We also obtain the neutron (n) non-elastic reaction cross sections for the same targets. Comparing the nA reaction cross sections σ nA rec to thenA annihilation cross sections σn A ann , we find that σn A ann is significantly larger than the σ nA rec , that is, the σn A ann /σ nA rec cross section ratio lies between the values of about 1.5 to 4.0 in the momentum region where comparison is possible. The dependence of then annihilation cross section on the projectile charge is also examined in comparison with the antiprotonp. Here we predict thepA annihilation cross section on the simplest assumption that bothpA andnA interactions have the same nuclear part of the optical potential but differs only in the electrostatic Coulomb interaction. Deviation from a such simple model extrapolation in measurements will provide new information on the difference betweennA andpA potentials. PACS numbers: 24.10.-i, 25.43.+t, 25.75.-q, 2

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“…Systematic measurements were performed at LEAR in the 80's and 90's with antiprotons (p) [1][2][3][4][5][6][7][8][9][10][11][12][13] and antineutrons (n) [14][15][16][17][18][19] at energies below 50 MeV and also with antiprotonic atoms (see [20]). Recently the ASACUSA Collaboration has measured the annihilation cross section (σ ann ) of antiprotons at the Antiproton Decelerator (AD) of CERN [21,22] at 5.3 MeV on medium and medium-heavy targets (Ni, Sn, Pt) [23].…”

Section: Introductionmentioning

confidence: 99%

Antiproton-nucleus annihilation cross section at low energy

et al. 2018

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Abstract. The antinucleon-nuclei annihilation cross sections at low energies were systematically measured at CERN in the 80's and 90's with the LEAR facility and later with the Antiproton Decelerator. Unfortunately only few data exist for very low energy antiprotons (p<500 MeV/c) on medium and heavy nuclei. A deeper knowledge is required by fundamental physics and can have consequence also in cosmology and medical physics. In order to fill the gap, the ASACUSA Collaboration has very recently measured the annihilation cross section of 100 MeV/c antiprotons on carbon. In the present work the experimental result is presented together with a comparison both with the antineutron data on the same target at the same energies and with the other existing antiproton data at higher energies.

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Annihilation cross-sections of antineutrons on C, Al, Cu, Sn and Pb at low momenta (180–280 MeV/c) with the OBELIX spectrometer

Cited by 14 publications

References 24 publications

Enhancement of annihilation cross sections by electric interactions between the antineutron and the field of a large nucleus

Enhancement of annihilation cross sections by electric interactions between the antineutron and the field of a large nucleus

Optical model potential analysis of n¯A and nA interactions

Antiproton-nucleus annihilation cross section at low energy

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