Gluon condensate and the effective gluon mass

Abstract

Using massive gauge invariant QCD we show explicity how power like corrections to$\Pi _{\mu v} \left( q \right) = i\int {dx} e^{iq'x} \left\langle {0\left| {j_\mu ^{em} \left( x \right)\bar j_v^{em} \left( 0 \right)} \right|0} \right\rangle$ arise. Using our result for the 1/q ⁴ contribution, a one to one correspondence is made between the gluon condensate and the effective gluon mass. By relating this mass to,$\langle 0|\frac{{\alpha _s }}{\pi }G_{\mu v}^2 |0\rangle$ a value ofm _gluon=750 MeV is found at −q ²=10 GeV². In addition, within the context of dimensional regularization, a new technique for evaluating two loop momentum integrals with massive propagators is introduced. This method is a derivative of the Mellin transform technique that was applied to ladder diagrams in the days of Reggeisation.