Heavy hybrid mesons in the QCD sum rule

TL;DR

This paper investigates the spectra and decay properties of heavy hybrid mesons using QCD sum rules, revealing near-degenerate binding energies and small pionic couplings, contributing to understanding heavy hybrid meson characteristics.

Contribution

It provides the first QCD sum rule analysis of heavy hybrid meson spectra and their pionic decay couplings in the heavy quark limit.

Findings

Binding energies of heavy hybrid doublets are nearly degenerate.

Pionic couplings between hybrid and conventional mesons are small.

Estimated partial decay widths suggest suppressed pionic decays.

Abstract

We study the spectra of the hybrid mesons containing one heavy quark ($q\bar{Q}g$) within the framework of QCD sum rules in the heavy quark limit. The derived sum rules are stable with the variation of the Borel parameter within their corresponding working ranges. The extracted binding energy for the heavy hybrid doublets $H^h(S^h)$ and $M^h(T^h)$ is almost degenerate. We also calculate the pionic couplings between these heavy hybrid and the conventional heavy meson doublets using the light-cone QCD sum rule method. The extracted coupling constants are rather small as a whole. With these couplings we make a rough estimate of the partial widths of these pionic decay channels.