Axial charges and magnetic moments of the decuplet pentaquark family
Hao-Song Li
TL;DR
The paper analyzes the decuplet of hidden-charm molecular pentaquarks within a constituent quark model, computing axial charges and magnetic moments to reveal nucleon-like spin content and a structured electromagnetic profile. Axial charges are derived by matching hadron-level and quark-level interactions, yielding axial couplings with d1 = 4/5 g_A and systematically larger charges than the octet, while magnetic moments show strong flavor–spin dependence and obey Hao-Song sum rules even with SU(3) breaking. The Hao-Song sum rules provide exact relations among magnetic moments for states sharing the same spin–flavor structure, offering robust probes of the internal multiquark dynamics. These results furnish benchmarks for future experimental analyses and theoretical efforts aimed at uncovering the molecular nature and internal dynamics of hidden-charm pentaquarks.
Abstract
We present a systematic calculation of the axial charges and magnetic moments for the decuplet of hidden-charm molecular pentaquarks within the framework of the constituent quark model. Our findings reveal that the axial charges of these states are comparable in magnitude to that of the nucleon. Furthermore, we find that their magnetic moments obey a set of sum rules (denoted the Hao-Song sum rules) which hold for states sharing the same spin-flavor configuration, even in the presence of SU(3) flavor symmetry breaking. These results provide crucial insights into the internal structure and dynamics of multiquark hadrons, offering valuable guidance for future experimental and theoretical investigations.$μ_{P_ψ^{Δ+}}- μ_{P_ψ^{\Delta0}}+μ_{P_{ψs}^{Σ-}}- μ_{P_{ψs}^{Σ+}} +μ_{P_{ψss}^{N0}}- μ_{P_{ψss}^{N-}}=0$, $ μ_{P_ψ^{Δ++}}+μ_{P_ψ^{Δ-}} +μ_{P_{ψsss}^{Λ-}}= 3μ_{P_{ψs}^{\Sigma0}}$.