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Probing the spin parity structure of hidden charm pentaquarks from spectroscopy and magnetic moments

Pallavi Gupta

TL;DR

This work probes the spin-parity structure of hidden-charm pentaquarks by marrying mass spectroscopy with magnetic-moment calculations in a hadronic molecular framework. Using a Gürsey-Radicati mass operator fitted to 41 baryons, the authors predict pentaquark spectra across SU(3) flavor octet and decuplet and assign JP values to observed states, while constructing explicit flavor-spin wavefunctions for electromagnetic analysis. Magnetic moments, computed from a constituent-quark model with L=0, reveal clear patterns across charge, strangeness, and SU(3) multiplets, providing a supplementary handle to refine JP assignments through sum rules and multiplet discrimination. The combined spectroscopy and magnetic observables favor an octet-dominated interpretation and yield concrete predictions for missing partners and their electromagnetic properties, testable by lattice QCD and future experiments.

Abstract

We investigate the spin parity JP assignments of experimentally observed hidden charm pentaquark states within a baryon meson molecular framework. The pentaquark mass spectrum is obtained using the Gursey Radicati mass formula, with parameters fixed through a global fit to 41 experimentally established hadron masses. The resulting spectrum is then used to assign JP quantum numbers to the observed pentaquark candidates. Within this framework, the nonstrange states Pc 4312, Pc4440, and Pc 4457 are identified with the JP = 1/2, 3/2, and 5/2 configurations, respectively. The recently reported Belle state Pcs4459, which carries strangeness, is interpreted as the strange member of the SU3 flavor octet with JP = 3/2. Magnetic moments are subsequently evaluated using explicitly constructed wave functions. Their systematic behavior across SU3 flavor multiplets and different spin parity assignments satisfies the expected sum-rule relations and indicates that magnetic moments can serve as a useful observable for refining the quantum-number identification of hidden charm pentaquark states in future studies.

Probing the spin parity structure of hidden charm pentaquarks from spectroscopy and magnetic moments

TL;DR

This work probes the spin-parity structure of hidden-charm pentaquarks by marrying mass spectroscopy with magnetic-moment calculations in a hadronic molecular framework. Using a Gürsey-Radicati mass operator fitted to 41 baryons, the authors predict pentaquark spectra across SU(3) flavor octet and decuplet and assign JP values to observed states, while constructing explicit flavor-spin wavefunctions for electromagnetic analysis. Magnetic moments, computed from a constituent-quark model with L=0, reveal clear patterns across charge, strangeness, and SU(3) multiplets, providing a supplementary handle to refine JP assignments through sum rules and multiplet discrimination. The combined spectroscopy and magnetic observables favor an octet-dominated interpretation and yield concrete predictions for missing partners and their electromagnetic properties, testable by lattice QCD and future experiments.

Abstract

We investigate the spin parity JP assignments of experimentally observed hidden charm pentaquark states within a baryon meson molecular framework. The pentaquark mass spectrum is obtained using the Gursey Radicati mass formula, with parameters fixed through a global fit to 41 experimentally established hadron masses. The resulting spectrum is then used to assign JP quantum numbers to the observed pentaquark candidates. Within this framework, the nonstrange states Pc 4312, Pc4440, and Pc 4457 are identified with the JP = 1/2, 3/2, and 5/2 configurations, respectively. The recently reported Belle state Pcs4459, which carries strangeness, is interpreted as the strange member of the SU3 flavor octet with JP = 3/2. Magnetic moments are subsequently evaluated using explicitly constructed wave functions. Their systematic behavior across SU3 flavor multiplets and different spin parity assignments satisfies the expected sum-rule relations and indicates that magnetic moments can serve as a useful observable for refining the quantum-number identification of hidden charm pentaquark states in future studies.
Paper Structure (5 sections, 12 equations, 3 figures, 8 tables)

This paper contains 5 sections, 12 equations, 3 figures, 8 tables.

Table of Contents

  1. Introduction
  2. Mass Spectroscopy
  3. Wavefunctions
  4. Magnetic Moments of Ground-State Hidden-Charm Pentaquark States
  5. Summary and Conclusions

Figures (3)

  • Figure 1: Comparison of GR-predicted pentaquark masses with experimental LHCb values and earlier results from Ref. PRL.
  • Figure 2: Magnetic moments of hidden-charm pentaquark states for different spin--parity assignments, comparing the decuplet $10_f$ and octet $8_{1f}$ flavor representations.
  • Figure 3: Magnetic moments of hidden-charm pentaquark states as functions of electric charge and strangeness for different spin--parity assignments.