Study of $qqq\bar{q}Q$ pentaquark system in the Chiral Quark Model

TL;DR

This study investigates heavy-flavor pentaquark systems using the chiral quark model, predicting possible charmed and bottomed pentaquark states and their structures, which could relate to experimentally observed resonances.

Contribution

The paper provides five-body dynamical calculations predicting new pentaquark candidates and their structures within the chiral quark model, extending understanding of heavy-flavor pentaquarks.

Findings

Identification of charmed pentaquark candidates for $ ext{Lambda}_c(2595)$ and $ ext{Lambda}_c(2625)$

Prediction of bottomed pentaquark candidates for $ ext{Lambda}_b(5912)$ and $ ext{Lambda}_b(5920)$

Discovery of high-spin states in the energy region of 3.2-3.3 GeV and 6.5-6.6 GeV

Abstract

With the discovery of some hidden-charm pentaquark resonances by the LHCb Collaboration, investigations of pentaquark states containing heavy quarks have aroused the interest of theorists. We study herein $qqq\bar{q}Q$ ($q = u$ or $d$, $Q=c$ or $b$) pentaquark system, in the framework of the chiral quark model. In consequence, some charmed and bottomed pentaquarks are considered to exist by five-body dynamical calculations. In the charm sector, $\Sigma_c\pi(IJ^P=0\frac{1}{2}^-)$ and $\Sigma_c^*\pi(IJ^P=0\frac{3}{2}^-)$ are possible candidates of $\Lambda_c(2595)$ and $\Lambda_c(2625)$, respectively. Besides, two high-spin states, $\Sigma_c^*\rho(IJ^P=0\frac{5}{2}^-)$ and $\Delta D^*(IJ^P=1\frac{5}{2}^-)$, are also found in the energy region of $3.2 \sim 3.3$ GeV. In the bottom sector, $\Sigma_b\pi(IJ^P=0\frac{1}{2}^-)$, $\Sigma_b^*\pi(IJ^P=0\frac{3}{2}^-)$ could be candidates of $\Lambda_b(5912)$ and $\Lambda_b(5920)$, respectively. And $\Sigma_b^*\rho(IJ^P=0\frac{5}{2}^-)$ and $\Delta B^*(IJ^P=1\frac{5}{2}^-)$ are found in the energy region of $6.5 \sim 6.6$ GeV. $\Sigma_c^{(*)}\pi$ and $\Sigma_b^{(*)}\pi$ are expected as compact states, while $\Sigma_c^*\rho$, $\Sigma_b^*\rho$, $\Delta D^*$ and $\Delta B^*$ are expected as molecular states.