Flavor-singlet hidden charm pentaquark

Irie, Yoya*; Oka, Makoto   ; Yasui, Shigehiro*

One type of hidden charm pentaquark with quark content in light-flavor singlet state is studied in the quark model. This state is analogous to the with in light-flavor octet, which was observed in LHC in 2015. Considering various combinations of color, spin, and light flavor as internal quantum numbers in , we investigate the mass ordering of the 's by adopting both the one-gluon exchange interaction and the instanton-induced interaction in the quark model. The most stable configuration of is identified to be total spin 1/2 in which the is combined to be color octet and spin 1, while the uds cluster is in a color octet state. The other color octet configurations, the total spin state with the spin 0, and the state with total spin and spin 1, are found as excited states. We also discuss possible decay modes of these hidden charm pentaquarks.