Strange tribaryons as K¯-mediated dense nuclear systems

We discuss the implications of recently discovered strange tribaryons in 4He(stopped-K−,p) S0(3115) and 4He(stopped-K−,n) S1(3140) within the framework of deeply bound K¯ states formed on shrunk nuclear cores. S1(3140) corresponds to T=0ppnK−, whereas S0(3115) to T=1pnnK−, which is an isobaric analog state of pppK−, predicted previously. The observed binding energies can be accounted for by including the relativistic effect and by invoking a medium-enhanced K¯N interaction by 15%. We propose various experimental methods to further study these and related bound systems.