LAUSR

Nijiati Yalikun,1, 2, ∗ Yong-Hui Lin,3, † Feng-Kun Guo,1, 2, ‡ Yuki Kamiya,1, § and Bing-Song Zou1, 2, 4, ¶ CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China Helmholtz-Institut für Strahlenund Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn, Germany School of Physics and Electronics, Central South University, Changsha 410083, China The effects of the ΣcD̄ -Λc(2595)D̄ coupled-channel dynamics and various one-bosonexchange (OBE) forces for the LHCb pentaquark states, Pc(4440) and Pc(4457), are reinvestigated. Both the pion and ρ-meson exchanges are considered for the ΣcD̄ -Λc(2595)D̄ coupled-channel dynamics. It is found that the role of the Λc(2595)D̄ channel in the descriptions of the Pc(4440) and Pc(4457) states is not significant with the OBE parameters constrained by other experimental sources. The naive OBE models with the short-distance δ(~r) term of the one-pion exchange (OPE) kept fail to reproduce the Pc(4440) and Pc(4457) states simultaneously. The OPE potential with the full δ(~r) term results in a too large mass splitting for the J = 1/2− and 3/2− ΣcD̄ ∗ bound states with total isospin I = 1/2. The OBE model with only the OPE δ(~r) term dropped may fit the splitting much better, but somewhat underestimates the splitting. Since the δ(~r) potential is from short-distance physics, which also contains contributions from the exchange of mesons heavier than those considered explicitly, we vary the strength of the δ(~r) potential and find that the masses of the Pc(4312), Pc(4440), and Pc(4457) can be reproduced simultaneously with the δ(~r) term in the OBE model reduced by about 80%. While two different spin assignments are possible to produce their masses, in the preferred description the spin-parities of the Pc(4440) and Pc(4457) are 3/2 − and 1/2−, respectively.