International Conference on Exotic Atoms and Related Topics - EXA2014

The ASACUSA collaboration has a wide physics program mainly focused to test CPT invariance through the spectroscopy of antihydrogen and of antiprotonic helium. In addition, a part of the experimental program concerns the measurement the antiproton annihilation cross sections on different nuclei at very low energy which is of interest both for nuclear physics and for fundamental fosmology. As regards nuclear physics, the measurements in the sub-MeV region can contribute for example to determine the parameters of the potential models, to investige the excitation process of the nuclear matter and to search nuclear resonances. In addition the cross section data can be useful for the cosmological models which try to explain the absence of antimatter in the observable universe by assuming that antimatter is confined within particular regions. These "islands" of antimatter can overlap with matter and their evolution would strongly depend on the value of the annihilation cross sections. Recently the first observation of in-flight antiproton-nucleus annihilation at 130 keV has been obtained with the ASACUSA detector [1] which demonstrates that the measurement of the cross section of the process is feasible at such extremely low energies. Here we present the results of the analysis of the data acquired with carbon, palladium and platinum targets and the evaluations of the cross sections for 130 keV antiprotons are reported. Reference H. Aghai-Khozani et al., Eur. Phys. J. Plus 127 (2012) 125