DOI 10.1007/s100529800855
Comment on "Infrared and pinching singularities
in out of
equilibrium QCD plasmas''
A. Niégawa
Department of Physics, Osaka City University, Sumiyoshi-ku, Osaka 558, Japan (e-mail: niegawa@sci.osaka-cu.ac.jp)
Received: 27 October 1997 / Revised version: 9 January 1998 / Published online: 10 March 1998
Abstract
Analyzing the dilepton production from out of equilibrium
quark-gluon plasma, Le Bellac and Mabilat have recently pointed out
that, in the reaction rate, the cancellation of mass (collinear)
singularities takes place only in physical gauges, and not in
covariant gauges. They then have estimated the contribution
involving pinching singularities. After giving a general argument
for the gauge independence of the production rate, we explicitly
confirm the gauge independence of the mass-singular part. The
contribution involving pinching singularities develops mass
singularities, which is also gauge dependent. This
additional'' contribution to the singular part is responsible for
the gauge independence of the total'' singular part.
Copyright Springer-Verlag
