Establishing the first hidden-charm pentaquark with strangeness

Abstract

We study the P_{cs}(4459)^0 recently observed by LHCb using the method of QCD sum rules. Our results support its interpretation as the {{bar{D}}}^* varXi _c hadronic molecular state of either J^P=1/2^- or 3/2^-. Within the hadronic molecular picture, the three LHCb experiments observing P_c and P_{cs} states (Aaij et al., Phys Rev Lett 115:072001, 2015; Aaij et al., Phys Rev Lett 122:222001, 2019; Aaij et al., arXiv:2012.10380 [hep-ex], 2012) can be well understood as a whole. This strongly supports the existence of hadronic molecules, whose studies can significantly improve our understanding on the construction of the subatomic world. To verify this picture, we propose to further investigate the P_{cs}(4459)^0 to examine whether it can be separated into two states, and to search for the {{bar{D}}} varXi _c molecular state of J^P=1/2^{-}.