Modified approach for calculating tensor vacuum susceptibility

By differentiating the dressed quark propagator with respect to a constant external tensor field, the linear response of the nonperturbative dressed quark propagator in the presence of the constant external tensor field can be obtained. From this we extract a general expression for the vacuum susceptibility which is needed in the QCD sum rule external field method for the coupling of tensor current to hadrons and compare it with the previous approaches. The numerical value of the tensor vacuum susceptibility are calculated within the framework of the rainbow-ladder approximation of the Dyson-Schwinger approach.