Eur. Phys. J. C 24, 439-446 (2002)
New contributions to heavy quark sum rulesJ. Portolés and P.D. Ruiz-Femenía
Departament de Física Teòrica, IFIC, Universitat de València-CSIC, Apt. Correus 22085, 46071 València, Spain
(Received: 11 February 2002 / Revised version: 14 March 2002 / Published online: 22 May 2002)
We analyze new contributions to the theoretical input in heavy quark sum rules and we show that the general theory of singularities of perturbation theory amplitudes yields the method to handle these specific features. In particular we study the inclusion of heavy quark radiation by light quarks at and of non-symmetric correlators at . Closely related with this is that we also propose a solution to the construction of moments of the spectral densities at where the presence of massless contributions invalidates the standard approach. We circumvent this problem through a new definition of the moments, providing an infrared safe and consistent procedure.
© Società Italiana di Fisica, Springer-Verlag 2002