EXA2011

The contribution reports on our recent study [1] of the interaction of antikaons with nuclear systems within an SU(3) chiral approach combined with coupled-channel T-matrix resummation techniques [2,3,4]. The K^- meson self energy operator is constructed from in-medium subthreshold K^-N scattering amplitudes derived within a chirally motivated model, which accounts for new SIDDHARTA data [5]. It is shown for the first time how to incorporate the strong energy and density dependence of the K^-N scattering amplitudes at and below threshold into self consistent evaluation of the K^- nuclear potential. This strong energy and density dependence of the scattering amplitudes leads to a deep K^- potential V_{K} in the nuclear medium, with the depth -ReV_{K}(ρ_{0}) of order 100 MeV, although the potential is shallow at threshold. Consequences for dynamical calculations of K^- nuclear quasi-bound states, for their binding energies and widths, are reported and discussed. The decay width induced by non mesonic K^-NN absorption and the role of p-wave K^-N subthreshold amplitudes associated with Σ(1385) are studied, as well. The calculated binding energies and widths are compared with the results of refs.[6,7,8]. [1] A. Cieplý, E. Friedman, A. Gal, D. Gazda, J. Mareš, arXiv:1102.4515 [nucl-th], subm. Phys. Lett. B. [2] A. Ramos, E. Oset, Nucl. Phys. A 671, 481 (2000). [3] B. Borasoy, R. Nissler, W. Weise, Eur. Phys. J A 25, 79 (2005), Phys. Rev. Lett. 94, 213401 (2005). [4] A. Cieplý, J. Smejkal, Eur. Phys. J A 43, 191 (2010). [5] G. Beer et al. [SIDDHARTA Collab.] , arXiv :0247548 [nucl-ex]. [6] J. Mareš, E. Friedman, A. Gal, Nucl. Phys. A 770, 84 (2006). [7] D. Gazda, E. Friedman, A. Gal, J. Mareš, Phys. Rev. C 76 (2007) 055204, ibid. 77 (2008) 045206. [8] W. Weise, R. Haertle, Nucl. Phys. A 804 (2008) 173.