Resonant singly heavy pentaquarks in the MlT bag model: mass spectra and strong decays

Abstract Exploring the limits of color interactions in multiquark states is an important topic. Within the bag confinement picture of hadrons, we find that for singly heavy pentaquark systems, the bag confinement radius falls precisely within the range of color interaction limits provided by lattice QCD (approximately 1.17–1.29 fm). This leads us to suggest that these singly heavy pentaquark states may lie close to the compact limit, yet retain the potential to form prominent resonant states. Inspired by singly heavy baryons, we consider their mirror pentaquark counterparts. By incorporating both chromomagnetic and color-electric interactions between heavy and strange quarks, we calculate the mass spectrum of singly heavy pentaquarks in the $$qqqQ\bar{q}$$ q q q Q q ¯ configuration and analyze the stability of their S-wave two-body strong decays. Our computations show that the masses of the singly heavy pentaquark system are generally about 500 MeV higher than those of the corresponding mirror baryon ground states, a result consistent with findings from chiral methods. Based on light-quark flavor symmetry, we establish a mass mapping relation between singly heavy pentaquarks and singly heavy baryons. The analysis of strong decays indicates that these singly heavy pentaquarks are unstable against strong decays, which aligns with our initial hypothesis.