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Titolo:
Pion production in nonequilibrium chiral perturbation theory - art. no. 016011
Autore:
Nicola, AG;
Indirizzi:
Univ Complutense, Dept Fis Teor 2, E-28040 Madrid, Spain Univ ComplutenseMadrid Spain E-28040 Fis Teor 2, E-28040 Madrid, Spain
Titolo Testata:
PHYSICAL REVIEW D
fascicolo: 1, volume: 6401, anno: 2001,
pagine: 6011 -
SICI:
0556-2821(20010701)6401:1<6011:PPINCP>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
HEAVY-ION COLLISIONS; FINITE-TEMPERATURE; PHASE-TRANSITION; HIGH-ENERGY; PARTICLE-PRODUCTION; EXPANDING UNIVERSE; LARGER DOMAINS; FIELD-THEORY; CONDENSATE; DYNAMICS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
--discip_EC--
Citazioni:
68
Recensione:
Indirizzi per estratti:
Indirizzo: Nicola, AG Univ Complutense, Dept Fis Teor 2, E-28040 Madrid, Spain Univ Complutense Madrid Spain E-28040 , E-28040 Madrid, Spain
Citazione:
A.G. Nicola, "Pion production in nonequilibrium chiral perturbation theory - art. no. 016011", PHYS REV D, 6401(1), 2001, pp. 6011

Abstract

We apply the formalism of chiral perturbation theory out of thermal equilibrium to describe explosive production of pions via the parametric resonance mechanism. To lowest order the Lagrangian is that of the nonlinear sigma model where the pion decay constant becomes a time-dependent function. Thismodel allows for a consistent nonequilibrium formulation within the framework of the closed time path method, where one-loop effects can be systematically accounted for and renormalized. We work in the narrow resonance regime where there is only one resonant band. The pion distribution function is peaked around the resonant band where the number of pions grow exponentially in time. The present approach is limited to remain below the back-reaction time, although it accounts for nearly all the pion production during the typical plasma lifetime. Our results agree with the analysis performed in the O(4) model. The space and time components. f(pi)(s,t)(t) are also analyzed. To one loop f(pi)(s)not equalf(pi)(t) unlike the equilibrium case and their final central values are lower than the initial ones. This effect can be interpreted in terms of a reheating of the plasma.

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Documento generato il 06/04/20 alle ore 08:32:28