Lattice QCD study for stringy excitation and role of UV gluons

TL;DR

This study uses lattice QCD to analyze how high-momentum gluons influence stringy excitations in quark systems, revealing that UV gluons significantly affect excited states but not the ground state.

Contribution

It demonstrates the role of UV gluons in gluonic excitations within quark systems, highlighting their impact on excited-state potentials in lattice QCD.

Findings

UV gluons significantly affect excited-state potentials.

Ground-state potentials are insensitive to UV-gluon removal.

Gluonic excitations remain around 1 GeV even after UV-gluon removal.

Abstract

In both cases of quark-antiquark (Q-Qbar) and three-quark (3Q) systems, we study ground-state and low-lying excited-state potentials in terms of the gluon-momentum component in the Coulomb gauge in SU(3) quenched lattice QCD. By introducing UV-cut in the gluon-momentum space, we investigate the "UV-gluon sensitivity" of the ground-state and excited-state potentials quantitatively. Such a non-quark-origin excitation is a purely gluonic excitation, which can be interpreted as a stringy excitation in the color flux-tube picture of hadrons. For both Q-Qbar and 3Q systems, the IR part of the ground-state potential is almost unchanged, even after cutting off high-momentum gluon component. On the other hand, we find more significant change of excited-state potential 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.