Determination of the possible quantum numbers for the newly observed $Ξ_b(6227)^0$ state

Abstract

The LHCb Collaboration recently reported the observation of a new excited bottom baryon Ξ b (6227) 0 and announced an improvement in the measurements related to the previously observed Ξ b (6227) − state. We conduct an analysis for Ξ b (6227) 0 state considering it as isospin partner of the Ξ b (6227) − resonance and possibly 1P or 2S excited state with spin J = 3 2 . The corresponding masses for both possibilities have consistent results with the experimental data, indicating that only with the mass sum rules, one can not make exact decision on the nature and quantum numbers of this state. To go further, the decays of these possible excited states to Ξ − b π + final state are also considered and the relevant strong coupling constants are extracted from the light cone sum rules. The obtained decay width values support the possibility of Ξ b (6227) 0 to be the 1P excited state of Ξ b (5945) 0 baryon.

Strong decays of the low-lying bottom strange baryons

“….8%, 2.3%, 65.1%, 10.8%. (14) Our present assignment for the Ξ b (6227) is consistent with previous works within the potential model [13], chiral quark model [14], Regge approach [16], and QCD sum rule [15,37], and then the theorists seem to reach a consensus on this state. However, it's worth noting that all of the Ξ ′ b (1P) states can decay into the Ξ b π and Λ b K channels under the mixing scheme.…”