Naslov
Cancellation of pinching singularities in out of equilibrium thermal field theory

Autori
Dadić, Ivan

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings of the 5th International Workshop on thermal field theories and their applications / - , 1998

Skup
5th International Workshop on thermal field theories and their applications

Mjesto i datum
Regensburg, Njemačka, 1998

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
pinching singularity; out of equilibrium; thermal field theory

Sažetak
Long standing problem in out-of-equilibrium thermal field theories are pinching singularities. We find that the expressions suspect of pinching require loop particles to be on the mass shell. This fact, with the help of threshold effect and similar effect due to spin, leads to the elimination of pinching in single self-energy insertion approximation to propagator in all propagators appearing in QED and QCD under very mild restrictions on particle densities. This, together with the cancellation of collinear singularities, allows the extraction of useful physical information contained in the imaginary parts of the two loop diagrams. In some cases of interest ($pi- ho $ interaction, electro-weak interaction, decay of Higgs particle, ...) none of the mentioned mechanisms works and one has to resort to the resummed Schwinger-Dyson series. These cases are more sensitive to the limitations related to the finite time range.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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