Strange hadronic matter with a weak Y-Y interaction

A modified quark meson coupling (MQMC) model is extended to include Lambda hyperons and Xi hyperons. The extended model is then used to study the equation of state (EOS) for strange hadronic matter. A weak Lambda-Lambda interaction deduced from recent observation of He-6(LambdaLambda) double hypernucleus is adopted in the calculation. The resultant EOS is compared with that deduced from a strong Lambda-Lambda interaction. It is found that while the system with the strong Lambda-Lambda interaction is more deeply bound than ordinary nuclear matter due to the opening of new degrees of freedom, the system with the weak Lambda-Lambda interaction is rather loosely bound compared to the latter. It is necessary to introduce the strange mesons sigma(*) and phi in the MQMC model to properly describe the interaction between the hyperons in either strong or weak Lambda-Lambda interaction cases.