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.
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