The Quark-Gluon Mixed Condensate g<\bar{q} sigma G q> in SU(3)c Quenched Lattice QCD

TL;DR

This study calculates the quark-gluon mixed condensate in SU(3) lattice QCD, revealing its significant magnitude and implications for QCD operator product expansion, using quenched lattice simulations with multiple quark masses.

Contribution

First lattice QCD calculation of the mixed condensate ratio g<ar{q} sigma G q> / <ar{q}q> across different quark masses, highlighting its importance.

Findings

The ratio m_0^2 is approximately 2.5 GeV^2 in the chiral limit.

The mixed condensate has a large value, indicating its significance in QCD.

The study provides a quantitative estimate of the mixed condensate in quenched lattice QCD.

Abstract

Using the SU(3)c lattice QCD with the Kogut-Susskind fermion at the quenched level, we study the quark-gluon mixed condensate g<\bar{q} sigma G q>, which is another chiral order parameter. For each current quark mass of m_q=21, 36, 52 MeV, we generate 100 gauge configurations in the 16^4 lattice with \beta = 6.0, and perform the measurement of the mixed condensate at 16 points in each gauge configuration. Using the 1600 data for each m_q, we find the ratio between the mixed condensate and the quark condensate, m_0^2 = g<\bar{q} sigma G q>/ <\bar{q}q> \simeq 2.5 GeV^2 at the lattice scale in the chiral limit. The large value of the mixed condensate suggests its importance in the operator product expansion in QCD.