2022/04/05 by Jian, Zhong-Yi, Zhu, Hong Qiang, Yang, Feng +3
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)
paper · doi:10.48550/arxiv.2204.01961
In 2019, two new structures Λb(6146) and Λb(6152) were observed by the LHCb Collaboration at the invariant mass spectrum of Λb0π+π-, which aroused a hot discussion about their inner structures. The Λb(6146) and Λb(6152) might still be molecular states because their masses are close to threshold of a B meson and a nucleon. In this work, we perform a systematical investigation of possible heavy baryonic molecular states from the BN interaction. Since the BN channel strongly couples to the B*N channel, the possible BN-B*N bound states are also studied. The interaction of the system considered is described by the t-channel σ, π, η ,ω, and ρ mesons exchanges. By solving the non-relativistic Schrödinger equation with the obtained one-boson-exchange potentials, the B(*)N bound states with different quantum numbers are searched. The calculation suggests that recently observed Λb(6146) can be assigned as a P-wave BN molecular state with spin parity JP=3/2+ or a BN-B*N bound state. However, assignment of Λb(6152) as an F-wave BN molecular is disfavored. The Λb(6152) can be explained as meson-baryon molecular state with a small BN component. The calculation also predict the existence of two S-wave BN-B*N bound states that can be related to the experimentally observed Λb(5912) and Λb(5920).