Shear viscosity of pion gas
| dc.creator | Nakano, Eiji | |
| dc.date | 2006-12-20 | |
| dc.date | 2007-03-21 | |
| dc.date.accessioned | 2026-07-07T07:52:48Z | |
| dc.date.available | 2026-07-07T07:52:48Z | |
| dc.description | Using chiral perturbation theory we investigate the QCD shear viscosity ($η$) to entropy density ($s$) ratio below the deconfinement temperature ($\sim 170$ MeV) with zero baryon number density. It is found that $η/s$ of QCD is monotonically decreasing in temperature ($T$) and reaches 0.6 with estimated $\sim 50%$ uncertainty at T=120 MeV. A naive extrapolation of the leading order result shows that $η/s$ reaches the $1/4π$ minimum bound proposed by Kovtun, Son, and Starinets using string theory methods at $T\sim 210$ MeV. This suggests a phase transition or cross over might occur at $T\lesssim 210$ MeV in order for the bound to remain valid. Also, it is natural for $η/s$ to stay close to the minimum bound around the phase transition temperature as was recently found in heavy ion collisions. | |
| dc.description | 13 pages, 4 figures, A contribution to lecture notes for ECT* school on RG and EFT (2006), the draft has already been submitted to editor. Some references were added | |
| dc.identifier | https://arxiv.org/abs/hep-ph/0612255 | |
| dc.identifier | http://arxiv.org/abs/hep-ph/0612255 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/126011 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Shear viscosity of pion gas | |
| dc.type | text |