〈qq¯〉and higher-dimensional-condensate contributions to the nonperturbative quark mass

Dimension-3, -4, and -5 condensate contributions to the quark propagator are evaluated in the presence of a nonzero current-quark mass ($m_L$) explicitly breaking Lagrangian chiral symmetry through the use of an operator-product expansion (OPE) of appropriate nonperturbative vacuum expectation values in the fixed-point gauge. A gauge-parameter-independent shift away from the purely perturbative propagator pole at $m_L$ is seen to occur, provided the corrected pole is identified self-consistently with the OPE mass parameter, a mass which differs from $m_L$ by incorporating contributions from nonperturbative condensates. The results obtained are argued to be valid to all orders in the OPE, and are shown to encompass the entire O($g_s^2$) contribution of nonperturbative condensates to the quark propagator. Phenomenological consequences at (and near) the $m_L$=0 chiral limit are also discussed.