Pentaquark states with the $QQQq\bar{q}$ configuration in a simple model

TL;DR

This paper estimates the masses of triply heavy pentaquark states with a specific quark configuration, suggesting they are likely broad and discussing implications for molecular states and baryon mass limits.

Contribution

It provides a simple estimation method for the masses of $QQQq\bar{q}$ pentaquarks and explores their possible widths and interpretations, extending understanding of heavy hadron structures.

Findings

Pentaquark states are probably not narrow if they exist.

Molecular interpretations are plausible for certain near-threshold states.

Upper mass limits for triply heavy baryons can be inferred from doubly heavy baryons.

Abstract

We discuss the mass splittings for the $S$-wave triply heavy pentaquark states with the $QQQq\bar{q}$ $(Q=b,c;q=u,d,s)$ configuration which is a mirror structure of $Q\bar{Q}qqq$. The latter configuration is related with the nature of $P_c(4380)$ observed by the LHCb Collaboration. The considered pentaquark masses are roughly estimated with a simple method. One finds that such states are probably not narrow even if they do exist. This leaves room for molecule interpretation for a state around the low-lying threshold of a doubly heavy baryon and a heavy-light meson, e.g. $\Xi_{cc}D$, if it were observed. As a by product, we conjecture that upper limits for the masses of the conventional triply heavy baryons can be determined by the masses of the conventional doubly heavy baryons.