Probing Matter Radii of Neutron-Rich Nuclei by Antiproton Scattering

We propose to use antiprotons to investigate the sizes of stable and neutron-rich exotic nuclei by measurements of the \pbar A absorption cross section along isotopic chains in inverse kinematics. The expected effects are studied theoretically in a microscopic model. The \pbar U optical potentials are obtained by folding free space \pbar N scattering amplitudes with HFB ground state densities and solving the scattering equations by direct integration. The mass dependence of absorption cross sections is found to follow closely the nuclear root-mean-square radii. The total absorption cross section is shown to be a superposition of cross sections describing partial absorption on neutrons and protons, respectively. Thus measuring the differential cross sections for absorption on neutrons and protons will give information on their respective distributions. In neutron-rich nuclei the outer neutron layer shields the absorption on the protons giving access to investigations of antiproton-neutron interactions in matter.Comment: 8 pages, 4 figure

How Deep is the Antinucleon Optical Potential at FAIR energies

The key question in the interaction of antinucleons in the nuclear medium concerns the deepness of the antinucleon-nucleus optical potential. In this work we study this task in the framework of the non-linear derivative (NLD) model which describes consistently bulk properties of nuclear matter and Dirac phenomenology of nucleon-nucleus interactions. We apply the NLD model to antinucleon interactions in nuclear matter and find a strong decrease of the vector and scalar self-energies in energy and density and thus a strong suppression of the optical potential at zero momentum and, in particular, at FAIR energies. This is in agreement with available empirical information and, therefore, resolves the issue concerning the incompatibility of G-parity arguments in relativistic mean-field (RMF) models. We conclude the relevance of our results for the future activities at FAIR.Comment: 13 pages, 5 figures, accepted version to appear in Phys. Lett.

Mise au point de detecteurs a emission secondaire

SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Diffusion elastique et inelastique d'antiprotons de 50 et 180 MeV sur des noyaux

SIGLECNRS RP 148 (684) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc