Workshop for young scientists with research interests focused on physics at FAIR

Antibaryon-nucleus bound states J. Hrtankova, J. Mares Nuclear Physics Institute, 250 68 Rez, Czech Republic The study of the antibaryon-nucleus interaction is an interesting issue as it provides valuable information about the behavior of the antibaryon ($\bar{B}$) in nuclear medium, the in-medium $\bar{B}N$ interaction as well as nuclear dynamics. The possibility of the existence of $\bar{B}$-nucleus bound states - and antiproton states in particular - has attracted much interest in recent years in view of future activities at FAIR [1-5]. This contribution reports on our recent calculations of $\bar{p}$ and $\bar{Y}$ ($Y = $\Lambda$, $\Sigma$, and $\Xi$) bound states in selected nuclei, performed within the relativistic mean-field (RMF) approach. First, the G-parity motivated antibaryon-meson coupling constants were employed and possible deviations from the G-parity values were taken into account by introducing a scaling factor [2]. Various RMF models were used, including a model with density-dependent couplings, in order to study model dependence of the extrapolation of equation of state to higher densities. Our calculations confirmed large polarization effects of the nuclear core caused by the presence of the antibaryon and revealed significant effect of the $\bar{B}$ self-interaction which was not considered in previous RMF calculations. Next, we focused on the calculations of $\bar{p}$ nuclear bound states using a potential consistent with $\bar{p}$-atomic data [5]. The imaginary part of the phenomenological optical potential was introduced to describe absorption of the $\bar{p}$ in the nuclear medium and all relevant decay channels were included. The reduction of the phase space for the annihilation products for deeply bound $\bar{p}$ states was taken into account while treating fully self-consistently energy and density dependencies of the corresponding suppression factors. As a result, the $\bar{p}$ absorption widths significantly decrease when the phase space suppression is considered. References: [1] T.J. Bürvenich, I.N. Mishustin, L.M. Satarov, J.A. Maruhn, H. Stöcker, W. Greiner, Phys. Lett. B 542 (2002) 261. [2] I.N. Mishustin, L.M. Satarov, T.J. Bürvenich, H. Stöcker, W. Greiner, Phys. Rev. C 71 (2005) 035201. [3] A.B. Larionov, I.N. Mishustin, L.M Satarov, W. Greiner, Phys. Rev. C 78 (2008) 014604. [4] T. Gaitanos, M. Kaskulov, H. Lenske, Phys. Lett. B 703 (2011) 193. [5] J. Pochodzalla, Phys. Lett. B 669 (2008) 306. [6] E. Friedman, A. Gal, J. Mares, Nucl. Phys. A 761 (2005) 283.