Penta-quark States with Strangeness, Hidden Charm and Beauty

Abstract

The classical quenched quark models with three constituent quarks provide a good description for the baryon spatial ground states, but fail to reproduce the spectrum of baryon excited states. More and more evidences suggest that unquenched effects with multi-quark dynamics are necessary ingredients to solve the problem. Several new hyperon resonances reported recently could fit in the picture of penta-quark states. Based on this picture, some new hyperon excited states were predicted to exist; meanwhile with extension from strangeness to charm and beauty, super-heavy narrow $N^{\ast }$ and $\hat{I}{›}^{\ast }$ resonances with hidden charm or beauty were predicted to be around 4.3 and 11 GeV, respectively. Recently, two of such $N^{\ast }$ with hidden charm might have been observed by the LHCb experiment. More of those states are expected to be observed in near future. This opens a new window in order to study hadronic dynamics for the multi-quark states.

Talk given at the 10th International Workshop on the Physics of Excited Nucleons (NSTAR2015), Osaka, May 25--28 2015