Quark-gluon mixed condensate [formula omitted] from lattice QCD

Abstract

We study the quark-gluon mixed condensate g〈 qσ μνGμν q〉, which is another chiral order parameter, in SU(3) c lattice QCD with the Kogut-Susskind fermion at the quenched level. Using 100 gauge configurations on the 16 4 lattice with β = 6.0, we measure g〈 σ μν G μν q〉 at 16 points in each gauge configuration for each current-quark mass of m q = 21, 36, 52 MeV. From the 1600 data for each m q , we find m 0 2 ≡ g〈 q σ μνG μνq〉/〈 q g〉⋍ 2.5 GeV 2 at the lattice scale of a −1 }- 2GeV in the chiral limit. The large value of g〈 qσ μνG μνq〉 suggests its importance in the operator product expansions in QCD. We also show our preliminary results of g〈 qσ μνG μνq〉 at finite temperature.