2019 Impact factor 4.389
Particles and Fields
Eur. Phys. J. C 5, 345-348
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.


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