Chirally motivated amplitudes for in-medium applications

A new fit of a chirally motivated coupled-channel model for meson–baryon interactions is presented including the recent SIDDHARTA data on the 1s level characteristics of kaonic hydrogen. The kaon–nucleon amplitudes generated by the model are fully consistent with our earlier studies. We argue that a sharp increase of the real part of the in-medium K−p amplitude at subthreshold energies provides a link between the shallow –nuclear optical potentials obtained microscopically from threshold interactions and the phenomenological deep ones deduced from kaonic atoms data. The impact on the A-dependence of the Λ-hypernuclear formation rates measured in reactions with stopped kaons is discussed too.