English

Bulk viscosity and the conformal anomaly in the pion gas

High Energy Physics - Phenomenology 2010-04-21 v2

Abstract

We calculate the bulk viscosity of the massive pion gas within Unitarized Chiral Perturbation Theory. We obtain a low temperature peak arising from explicit conformal breaking due to the pion mass and another peak near the critical temperature, dominated by the conformal anomaly through gluon condensate terms. The correlation between bulk viscosity and conformal breaking supports a recent QCD proposal. We discuss the role of resonances, heavier states and large-NcN_c counting.

Keywords

Cite

@article{arxiv.0809.4663,
  title  = {Bulk viscosity and the conformal anomaly in the pion gas},
  author = {D. Fernandez-Fraile and A. Gomez Nicola},
  journal= {arXiv preprint arXiv:0809.4663},
  year   = {2010}
}

Comments

Revised version accepted in Phys.Rev.Lett. 4 pages, 3 figures

R2 v1 2026-06-21T11:24:37.737Z