Analysis of the $P_c(4380)$ and $P_c(4450)$ as pentaquark states in the diquark model with QCD sum rules

TL;DR

This paper investigates the nature of the $P_c(4380)$ and $P_c(4450)$ pentaquark states using diquark models and QCD sum rules, providing mass predictions that support their classification as specific pentaquark states.

Contribution

It introduces a diquark-diquark-antiquark interpolating current approach combined with QCD sum rules to analyze pentaquark states, including vacuum condensate contributions up to dimension-10.

Findings

Predicted masses support $P_c(4380)$ as ${3/2}^-$ pentaquark.

Predicted masses support $P_c(4450)$ as ${5/2}^+$ pentaquark.

Method effectively distinguishes pentaquark quantum numbers.

Abstract

In this article, we construct the diquark-diquark-antiquark type interpolating currents, and study the masses and pole residues of the $J^P={\frac{3}{2}}^-$ and ${\frac{5}{2}}^+$ hidden-charmed pentaquark states in details with the QCD sum rules by calculating the contributions of the vacuum condensates up to dimension-10 in the operator product expansion. In calculations, we use the formula $\mu=\sqrt{M^2_{P_c}-(2{\mathbb{M}}_c)^2}$ to determine the energy scales of the QCD spectral densities. The present predictions favor assigning the $P_c(4380)$ and $P_c(4450)$ to be the ${\frac{3}{2}}^-$ and ${\frac{5}{2}}^+$ pentaquark states, respectively.