On the massless contributions to the vacuum polarization of heavy quarks

Abstract
Groote and Pivovarov have noticed a possible fault in the use of sum rules involving two-point correlation functions to extract information on heavy quark parameters, due to the presence of massless contributions that invalidate the construction of moments of the spectral densities (2002 JETP Lett. 75 221). Here we show how to circumvent this problem through a new definition of the moments, providing an infrared safe and consistent procedure.