Interpretation of the observed $Λ_b(6146)^0$ and $Λ_b(6152)^0$ states as 1$D$ bottom baryons

Abstract

The measured masses and strong decays of Λ b (6146) 0 and Λ b (6152) 0 required us to decode them as the 1D excited states with J P = 3/2 + and J P = 5/2 + , respectively. Under the suggested assignment, the masses and total decay widths of Λ b (6146) 0 and Λ b (6152) 0 can be explained. As a J P = 3/2 + state, the Λ b (6146) 0 should mainly decay into Σ b (5815)π. However, this theoretical result is in contradiction to the measurement since no significant Λ b (6146) 0 → Σ b (5815) ± π ∓ signals were observed by the LHCb. The possible explanations to this difficulty are mentioned. For completeness, we present the prediction of masses and decay widths of other unseen 1D bottom baryons in this work. Our results could provide some important clues for the upcoming experiments.

An updated review of the new hadron states

“…This problem was further investigated in Refs. [263,264] using two similar quark models, and the same conclusion was obtained, which needs to be clarified in the future.…”

“…Based on the theoretical studies of Refs. [264,273], the Ξ b (6327) and Ξ b (6333) were suggested by LHCb to be the Ξ b (1D) states of J P = 3/2 + and 5/2 + , belonging to the [ 3F , 2, 0, λλ] doublet. Hence, they may be the partner states of the Λ b (6146) and Λ b (6152).…”

$Λ_b(6146)^0$ state newly observed by LHCb

“…For completeness, we also calculated the spectroscopic parameters of its charmed partner Λ c state with the same quantum numbers. The result for the mass of the Λ b state was obtained to be m Λ b = (6144 ± 68) MeV, which is in a good consistency with other theoretical predictions: m Λ b = 6147 MeV [33], m Λ b = 6190 MeV [18], m Λ b = 6181 MeV [17], m Λ b = 6145 MeV [7], m Λ b = 6149 MeV [84], and 6.01 +0.20 −0.12 GeV [42]. Our result on the mass of the Λ b is in accord with the experimental data of the LHCb Collaboration, as well.…”