Gluonic Transversity from Lattice QCD

TL;DR

This paper explores the gluonic structure of the $$ meson using lattice QCD, focusing on the first investigation of gluonic transversity and related gluonic distributions, revealing insights into gluonic degrees of freedom.

Contribution

It introduces the first lattice QCD study of gluonic transversity in the $$ meson and examines the gluonic analogue of the Soffer bound, providing new insights into gluonic structure.

Findings

Gluonic transversity can be probed via lattice QCD for the first time.

The gluonic analogue of the Soffer bound is saturated at 80%.

This work paves the way for studying gluonic structure in nucleons and nuclei.

Abstract

We present an exploratory study of the gluonic structure of the $\phi$ meson using lattice QCD (LQCD). This includes the first investigation of gluonic transversity via the leading moment of the twist-two double-helicity-flip gluonic structure function $\Delta(x,Q^2)$. This structure function only exists for targets of spin $J\ge1$ and does not mix with quark distributions at leading twist, thereby providing a particularly clean probe of gluonic degrees of freedom. We also explore the gluonic analogue of the Soffer bound which relates the helicity flip and non-flip gluonic distributions, finding it to be saturated at the level of 80%. This work sets the stage for more complex LQCD studies of gluonic structure in the nucleon and in light nuclei where $\Delta(x,Q^2)$ is an 'exotic glue' observable probing gluons in a nucleus not associated with individual nucleons.