Hidden-charm pentaquarks: Electromagnetic structure in a diquark--diquark--antiquark model

TL;DR

This paper calculates the magnetic dipole moments of hidden-charm pentaquarks using QCD sum rules, revealing how electromagnetic properties vary with internal quark arrangements and aiding in distinguishing structural models.

Contribution

It provides a systematic QCD sum rule analysis of the magnetic moments of hidden-charm pentaquarks with different internal configurations, highlighting their sensitivity to quark arrangements.

Findings

Magnetic moments strongly depend on internal quark configurations.

Significant differences in magnetic moments between molecular and compact models.

Electromagnetic observables can discriminate between pentaquark structural models.

Abstract

We systematically investigate the electromagnetic properties of exotic states whose internal structures remain uncertain and for which different models have been proposed. In this work, we focus on the magnetic dipole moments of hidden-charm pentaquark states using QCD light-cone sum rules with four distinct interpolating currents. The analysis accounts for contributions from both light and charm quark sectors, as well as higher-dimensional operators, ensuring convergence of the operator product expansion and dominance of the ground-state pole. Our results demonstrate a strong dependence of the magnetic moments on the internal quark configurations and spin alignments, revealing substantial variations among the different currents despite identical quark content and quantum numbers. Comparisons with existing studies indicate that while molecular-type predictions show general agreement, compact configurations yield markedly different values, including significant differences in sign and magnitude. These findings therefore underscore the sensitivity of electromagnetic observables to the internal structure of exotic hadrons and highlight their potential as probes to discriminate between competing structural models for spin-parity assignments and underlying quark dynamics.