Strong three-meson couplings of $J/\psi$ and $\eta_c$

TL;DR

This paper calculates strong meson couplings involving charmonium states using a relativistic quark model, finding higher values than previous QCD sum rule estimates, which could impact understanding of meson interactions.

Contribution

The study introduces a dispersion approach within a relativistic constituent quark model to compute strong meson couplings involving $J/ar{psi}$ and $ar{eta}_c$, providing results that differ from prior QCD sum rule estimates.

Findings

Higher coupling values than previous QCD sum rule results.

Form factors satisfy heavy-quark limit constraints.

Results obtained across a broad range of momentum transfers.

Abstract

We discuss the strong couplings $g_{PPV}$ and $g_{VVP}$ for vector ($V$) and pseudoscalar ($P$) mesons, at least one of which is a charmonium state $J/\psi$ or $\eta_c$. The strong couplings are obtained as residues at the poles of suitable form factors, calculated in a broad range of momentum transfers using a dispersion formulation of the relativistic constituent quark model. The form factors obtained in this approach satisfy all constraints known for these quantities in the heavy-quark limit. Our results suggest sizably higher values for the strong meson couplings than those reported in the literature from QCD sum rules.