Heaviside transform with respect to the mass in QCD
  We propose the use of Heaviside transform with respect to the quark mass to investigate dynamical aspects of QCD. We show that at large momentum transfer the transformed propagator of massive quarks behaves softly and thus the dominant effect of explicit chiral symmetry breaking disappears through Heaviside transform. This suggests that the massless approximation would be more convenient to do in the transformed quantity than in the original one. As an example of explicit approximation, we estimate the massless value of the quark condensate. 
H. Yamada