Possible pentaquarks with heavy quarks

TL;DR

This study explores potential hidden-charm and hidden-bottom pentaquarks using a quark delocalization color screening model, suggesting specific molecular states that could explain observed pentaquarks and predicting new resonance states.

Contribution

It introduces a detailed theoretical analysis of hidden-charm and hidden-bottom pentaquarks, proposing specific molecular configurations and explaining observed states within this framework.

Findings

$Nar{ ext{eta}}_c$ and $NJ/ ext{psi}$ are bound states with channel coupling.

$P_c(4380)$ can be explained as a $ ext{Sigma}_c^* D$ molecular state.

$Sigma_c^* D^*$ is a resonance, not matching $P_c(4450)$ due to opposite parity.

Abstract

Inspired by the discovery of two pentaquarks $P_{c}(4380)$ and $P_{c}(4450)$ at the LHCb detector, we study possible hidden-charm molecular pentaquarks in the framework of quark delocalization color screening model. Our results suggest that both $N\eta_{c}$ with $IJ^{P}=\frac{1}{2}\frac{1}{2}^{-}$ and $NJ/\psi$ with $IJ^{P}=\frac{1}{2}\frac{3}{2}^{-}$ are bounded by channels coupling. However, $NJ/\psi$ with $IJ^{P}=\frac{1}{2}\frac{3}{2}^{-}$ may be a resonance state in the $D-$wave $N\eta_{c}$ scattering process. Moreover, $P_{c}(4380)$ can be explained as the molecular pentaquark of $\Sigma^{*}_{c}D$ with quantum numbers $IJ^{P}=\frac{1}{2}\frac{3}{2}^{-}$. The state $\Sigma^{*}_{c}D^{*}$ with $IJ^{P}=\frac{1}{2}\frac{5}{2}^{-}$ is a resonance, it may not be a good candidate of the observed $P_{c}(4450)$ because of the opposite parity of the state to $P_{c}(4380)$, although the mass of the state is not far from the experimental value. In addition, the calculation is extended to the hidden-bottom pentaquarks, the similar properties as that of hidden-charm pentaquarks system are obtained.