Establishing the first hidden-charm pentaquark with strangeness

Abstract

We study the Pcs(4459) recently observed by LHCb using the method of QCD sum rules. Our results support its interpretation as the D¯ ∗Ξc hadronic molecular state of either JP= 1 / 2 - or 3 / 2 -. Within the hadronic molecular picture, the three LHCb experiments observing Pc and Pcs 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 Pcs(4459) to examine whether it can be separated into two states, and to search for the D¯ Ξc molecular state of JP= 1 / 2 -.