Statistical production of antikaon nuclear bound states in heavy ion collisions

Recently it was conjectured that the strongly attractive antikaon–nucleon potential can result in the formation of antikaon nuclear bound states. We discuss the formation of such states as possible residues in heavy ion collisions. In this context, we calculate the excitation functions of single- and double-K− clusters in terms of the statistical thermal model. We show that, if such objects indeed exist, then, in heavy ion collisions, the single-K− clusters are most abundantly produced at present SIS energies, while the double-K− clusters show a pronounced maximum yield in the energy domain of the future accelerator at GSI. This is a direct consequence of: (i) the baryonic dominance in low energy heavy ion collisions and the large baryonic content of the antikaonic bound states; (ii) the strong energy dependence of strangeness production at low energies. The production yields of double-strange clusters is compared with that of double strange baryons. It is shown that at SIS energy there is a linear scaling relation of the Ξ−/K+ with K+/p yields ratio.