Compact pentaquark structures
AbstractWe investigated the possibility that the lightest pentaquark state recently reported by the LHCb Collaboration [R. Aaij et al., Phys. Rev. Lett. 115, 072001 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.072001; 117, 082002 (2016)10.1103/PhysRevLett.117.082002; 117, 082003 (2016)10.1103/PhysRevLett.117.082003], Pc+(4380), could be described as a compact pentaquark state. By using very general arguments, dictated by symmetry considerations, we described the pentaquark states within a group theory approach. A complete classification of all possible states and quantum numbers, which can be useful both to the experimentalists in their search for new findings and to theoretical model builders, is given, without introducing any particular dynamical model. Some predictions are provided by means of a Gürsey-Radicati inspired mass formula. We have reproduced the mass and the quantum numbers of the lightest pentaquark state reported by LHCb, Pc+(4380), and have predicted other pentaquark resonances which belong to the same multiplet as the lightest one. Having calculated the masses of these resonances, we suggest possible bottom baryon decay channels which involve the predicted resonances as intermediate states. Finally, we have computed the partial decay widths for all the predicted pentaquark resonances.