The quark-gluon Mixed Condensate calculated via Field Correlators

Abstract

The quark-gluon mixed condensate $g<\bar{q}{\sigma }_{\mu \nu }{F}_{\mu \nu }q>$ is calculated in the Gaussian approximation of the Field Correlator Method. In the large N_c limit and for zero mass quarks one obtains a simple result, $m_0^2\equiv \frac{g<\bar{q}{\sigma }_{\mu \nu }{F}_{\mu \nu }q>}{<\bar{q}q>}=\frac{16\sigma }{\pi }$, where $\sigma$ is the string tension. For a standard value $\sigma =0.18Ge{V}^2$ one obtains $m_0^2=1Ge{V}^2$ in good agreement with the QCD sum rules estimate $m_0^2=(0.8\pm 0.2)Ge{V}^2$ and the latest lattice result $m_0^2\cong 1Ge{V}^2$.

10 pages, no figures; discussion of accuracy of the result added and misprints corrected