Interplay of quark and meson degrees of freedom in a near-threshold resonance

TL;DR

This paper explores how quark and meson interactions influence near-threshold resonances, revealing unique properties like S-matrix zeros, with implications for experimental and lattice QCD studies.

Contribution

It demonstrates that weakly coupled quark and meson poles can produce unusual resonance features, including zeros in the scattering matrix.

Findings

Near-threshold resonances can have zeros in the scattering t-matrix.

Both quark and meson dynamics can generate weakly coupled poles.

Implications for production reactions and lattice QCD studies are discussed.

Abstract

We investigate the interplay of quark and meson degrees of freedom in a physical state representing a near-threshold resonance for the case of a single continuum channel. We demonstrate that such a near-threshold resonance may possess quite peculiar properties if both quark and meson dynamics generate weakly coupled near-threshold poles in the S-matrix. In particular, the scattering t-matrix may possess zeros in this case. We also discuss possible implications for production reactions as well as studies within lattice QCD.