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

U. Ozdem

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.

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

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.
Paper Structure (7 sections, 27 equations, 2 figures, 4 tables)

This paper contains 7 sections, 27 equations, 2 figures, 4 tables.

Table of Contents

  1. Introduction
  2. Theoretical Formalism
  3. The hadronic representation: Parameterizing the physical process
  4. The QCD representation: Calculating with quarks and gluons
  5. Deriving the sum rule and isolating the magnetic moment
  6. Results and discussions
  7. Summary and conclusions

Figures (2)

  • Figure 1: CVG (left panel) and PC (right panel) analyses for the magnetic dipole moment of the $P_{\psi}^{N}$ pentaquark, obtained from the current $J_2(x)$ as a function of the Borel parameter $\mathrm{M}^{2}$. The curves are computed using $\mathrm{s}_{0}$-averaging over the continuum threshold interval given in Table \ref{['parameter']}. In the right panel, the vertical lines mark the chosen Borel region, and the horizontal line indicates the minimum $\mathrm{s}_{0}$-averaged PC value within this region.
  • Figure 2: Magnetic moments of the $P_{\psi}^{N}$ pentaquarks as a function of $\mathrm{M^2}$ for three different values of $\mathrm{s_0}$. The region enclosed between the vertical lines denotes the working interval of $\mathrm{M^2}$.