Stringy excitation and role of UV gluons in lattice QCD

TL;DR

This study investigates how high-momentum gluons affect the potentials in quark-antiquark systems using lattice QCD, revealing that UV gluons significantly influence excited states but not the ground state.

Contribution

It introduces a UV-cut method in gluon-momentum space to analyze the UV-gluon sensitivity of quark-antiquark potentials in lattice QCD.

Findings

Ground-state potential remains stable after UV-gluon removal.

Excited-state potential shows significant change with UV-gluon cut.

Low-lying gluonic excitation persists around 1 GeV despite UV-gluon removal.

Abstract

Using SU(3) quenched lattice QCD, we study ground-state and low-lying even-parity excited-state potentials of quark-antiquark systems in terms of the gluon-momentum component in the Coulomb gauge. By introducing UV-cut in the gluon-momentum space, we investigate the "UV-gluon sensitivity" of the ground-state and excited-state potentials and the stringy excitation quantitatively. Even after cutting off high-momentum gluon component above 1.5GeV, the IR part of the ground-state potential is almost unchanged. On the other hand, the change of excited-state potential is more significant by the cut of UV-gluons. However, even after the removal of UV-gluons, the magnitude of the low-lying gluonic excitation remains to be of the order of 1GeV.