The study of the antiproton ( p¯ ) annihilation cross section on nuclei at low energies (eV-MeV region) has implications for fundamental cosmology as well as for nuclear physics. Concerning the former, different models try to explain the matter/antimatter asymmetry in the universe assuming the existence of the so-called “islands” where antinucleon-nucleon annihilations occur in the border region, while, from the nuclear physics point of view, the annihilation process is a valuable tool to evaluate the neutron/proton ratio in order to probe the external region of the nucleus. The existing data of antinucleon-nucleon (or -nucleus) annihilation cross-sections are mainly confined to energies above ≈1 MeV, while the cross section measured at LEAR in the 80’s-90’s. The ASACUSA collaboration at CERN recently measured antiproton annihilation cross section on different kinds of nuclei with a p¯ kinetic energy of 5.3 MeV. Such results proved compatibility with the black-disk model with the Coulomb correction. But till now experimental difficulties prevented the investigation at energies below ≈1 MeV. In 2012, the 100 keV region has been investigated for the first time . We present here the first preliminary results of this experiment.

Experimental investigation of ap130 keV kinetic energy antiprotons annihilation on nuclei

Mascagna, V.;PREST, MICHELA;
2014-01-01

Abstract

The study of the antiproton ( p¯ ) annihilation cross section on nuclei at low energies (eV-MeV region) has implications for fundamental cosmology as well as for nuclear physics. Concerning the former, different models try to explain the matter/antimatter asymmetry in the universe assuming the existence of the so-called “islands” where antinucleon-nucleon annihilations occur in the border region, while, from the nuclear physics point of view, the annihilation process is a valuable tool to evaluate the neutron/proton ratio in order to probe the external region of the nucleus. The existing data of antinucleon-nucleon (or -nucleus) annihilation cross-sections are mainly confined to energies above ≈1 MeV, while the cross section measured at LEAR in the 80’s-90’s. The ASACUSA collaboration at CERN recently measured antiproton annihilation cross section on different kinds of nuclei with a p¯ kinetic energy of 5.3 MeV. Such results proved compatibility with the black-disk model with the Coulomb correction. But till now experimental difficulties prevented the investigation at energies below ≈1 MeV. In 2012, the 100 keV region has been investigated for the first time . We present here the first preliminary results of this experiment.
2014
antiprotons, annihilation cross section, nuclear physics
Aghai Khozani, H.; Barna, D.; Corradini, M.; Hayano, R.; Hori, M.; Kobayashi, T.; Leali, M.; Lodi Rizzini, E.; Mascagna, V.; Prest, Michela; Soter, A....espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2018680
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