Eur. Phys. J. C 24, 439-446 (2002)
DOI: 10.1007/s10052-002-0954-6
New contributions to heavy quark sum rules
J. Portolés and P.D. Ruiz-FemeníaDepartament 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)
Abstract
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
