2023/08/01 by Ke, Hong-Wei, Lu, Fang, Pang, Hai +2
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2308.00582
The measurements on a few pentaquarks states Pc(4440), Pc(4457) and Pcs(4459) excite our new interests about their structures. Since the masses of Pc(4440) and Pc(4457) are close to the threshold of Σc D^*, in the earlier works, they were regarded as molecular states of Σc D^* with quantum numbers I(JP)=(1)/(2)((1)/(2)-) and (1)/(2)((3)/(2)-), respectively. In a similar way Pcs(4459) is naturally considered as a Ξc D^* bound state with I=0. Within the Bethe-Salpeter (B-S) framework we systematically study the possible bound states of Λc D^*, Σc D^*, Ξc D^* and Ξc' D^*. Our results indicate that Σc D^* can form a bound state with I(JP)=(1)/(2)((1)/(2)-), which corresponds to Pc(4440). However for the I(JP)=(1)/(2)((3)/(2)-) system the attraction between Σc and D^* is too weak to constitute a molecule, so Pc(4457) may not be a bound state of Σc D^* with I(JP)=(1)/(2)((3)/(2)-). As Ξc D^* and Ξc' D^* systems we take into account of the mixing between Ξc and Ξ'c and the eigenstets should include two normal bound states Ξc D^* and Ξc' D^* with I(JP)=(1)/(2)((1)/(2)-) and a loosely bound state Ξc D^* with I(JP)=(1)/(2)((3)/(2)-). The conclusion that two Ξc D^* bound states exist, supports the suggestion that the observed peak of Pcs(4459) may hide two states Pcs(4455) and Pcs(4468). Based on the computations we predict a bound state Ξc' D^* with I(JP)=(1)/(2)((1)/(2)-) but not that with I(JP)=(1)/(2)((3)/(2)-). Further more accurate experiments will test our approach and results.