Experimental investigation of ≈130 keV kinetic energy antiprotons annihilation on nuclei

H. Aghai-Khozani, D. Barna, M. Corradini, R. Hayano, M. Hori, T. Kobayashi, M. Leali, E. Lodi-Rizzini, V. Mascagna, M. Prest, A. Soter, K. Todoroki, E. Vallazza, L. Venturelli, N. Zurlo

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The study of the antiproton (Formula presented.) 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 (Cohen et al. Astrophys. J. 495, 539–549, 1998), 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 (Gupta et al. Nucl. Phys. B 70(3), 414–424, 1974). 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 (mostly with light targets Agnello et al. Phys. Lett. B 256, 349–353, 1991; Bertin et al. Phys. Lett. B 369, 77–85, 1996; Bertin et al. Phys. Lett. B 414, 220–228, 1997; Zenoni et al. Phys. Lett. B 461, 405–412, 1999; Bianconi et al. Phys. Lett. B 481, 194–198, 2000; Bianconi et al. Phys. Lett. B 492, 254–258, 2000) showed an unexpected behaviour for energies below 1 MeV (Bianconi et al. Phys. Lett. B 483, 353–359, 2000; Bianconi et al. Phys. Rev. C 62, 014611-7, 2000; Batty et al. Nucl. Phys. A 689, 721–740, 2001). The results showed a saturation with the atomic mass number against the A2/3 trend which is observed for higher energies (being A the target mass number). The ASACUSA collaboration at CERN recently measured antiproton annihilation cross section on different kinds of nuclei with a (Formula presented.) kinetic energy of 5.3 MeV (Bianconi et al. Phys. Lett. B 704, 461–466, 2011; Corradini et al. Nucl. Instr. Methods A 711, 12–20, 2013). 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 (Aghai-Khozani et al. Eur. Phys. J. Plus 127, 125–128, 2012). We present here the first preliminary results of this experiment.

Original languageEnglish
Pages (from-to)31-36
Number of pages6
JournalHyperfine Interactions
Issue number1-3
Publication statusPublished - Oct 14 2014


  • Annihilation cross section
  • Antiproton

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Nuclear and High Energy Physics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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    Aghai-Khozani, H., Barna, D., Corradini, M., Hayano, R., Hori, M., Kobayashi, T., Leali, M., Lodi-Rizzini, E., Mascagna, V., Prest, M., Soter, A., Todoroki, K., Vallazza, E., Venturelli, L., & Zurlo, N. (2014). Experimental investigation of ≈130 keV kinetic energy antiprotons annihilation on nuclei. Hyperfine Interactions, 229(1-3), 31-36. https://doi.org/10.1007/s10751-014-1054-3