Transport coefficients and resonances for a meson gas in chiral perturbation theory



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Fernández Fraile, Daniel and Gómez Nicola, Ángel (2009) Transport coefficients and resonances for a meson gas in chiral perturbation theory. European physical journal C, 62 (1). pp. 37-54. ISSN 1434-6044

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We present recent results on a systematic method to calculate transport coefficients for a meson gas (in particular, we analyze a pion gas) at low temperatures in the context of Chiral Perturbation Theory (ChPT). Our method is based on the study of Feynman diagrams taking into account collisions in the plasma by means of the non-zero particle width. This implies a modification of the standard ChPT power counting scheme. We discuss the importance of unitarity, which allows for an accurate high-energy description of scattering amplitudes, generating dynamically the rho(770) and f(0)(600) mesons. Our results are compatible with analyses of kinetic theory, both in the non-relativistic very low-T regime and near the transition. We show the behavior with temperature of the electrical and thermal conductivities as well as of the shear and bulk viscosities. We obtain the result that the bulk viscosity is negligible against the shear viscosity, except near the chiral phase transition where the conformal anomaly might induce larger bulk effects. Various asymptotic limits for transport coefficients, large-N(c) scaling and some applications to heavy-ion collisions are studied.

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© Springer-Verlag / Società Italiana di Fisica 2009.
Hot Quarks Conference 2008 (2008. Aspen, CO).
We would like to thank D. Kharzeev and R. Venugopalan for very useful conversations. We also acknowledge fi- nancial support from the Spanish research projects FPA2004-02602, FPA2005-02327, PR34/07-1856-BSCH, UCM-CAM 910309/08, FPA2007-29115-E and from the F.P.I. Programme (BES-2005-6726).

Uncontrolled Keywords:Phase-transition; Pion-scattering; Field-theory; Qcd; Thermodynamics; Quark; Temperature; Viscosity; Plasma; Mass
Subjects:Sciences > Physics > Physics-Mathematical models
Sciences > Physics > Mathematical physics
ID Code:30325
Deposited On:25 May 2015 07:43
Last Modified:10 Dec 2018 15:09

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