Large-N pion scattering at finite temperature: The f(0)(500) and chiral restoration
We consider the O(N + 1)/O(N) nonlinear sigma model for large N as an effective theory for low-energy QCD at finite temperature T, in the chiral limit. At T = 0 this formulation provides a good description of scattering data in the scalar channel and dynamically generates the f_(0)(500) pole, the po...
| Autores: | , , |
|---|---|
| Formato: | artículo |
| Fecha de publicación: | 2016 |
| País: | España |
| Recursos: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/23197 |
| Acesso em linha: | https://hdl.handle.net/20.500.14352/23197 |
| Access Level: | acceso abierto |
| Palavra-chave: | 51-73 Perturbation-theory Limit Física-Modelos matemáticos Física matemática |
| Resumo: | We consider the O(N + 1)/O(N) nonlinear sigma model for large N as an effective theory for low-energy QCD at finite temperature T, in the chiral limit. At T = 0 this formulation provides a good description of scattering data in the scalar channel and dynamically generates the f_(0)(500) pole, the pole position lying within experimental determinations. Previous T = 0 results with this model are updated using newer analysis of pion scattering data. We calculate the pion scattering amplitude at finite T and show that it exactly satisfies thermal unitarity, which had been assumed but not formally proven in previous works. We discuss the main differences with the T = 0 result, and we show that one can define a proper renormalization scheme with T = 0 counterterms such that the renormalized amplitude can be chosen to depend only on a few parameters. Next, we analyze the behavior of the f(0)(500) pole at finite T, which is consistent with chiral symmetry restoration when the scalar susceptibility is saturated by the f_(0)(500) state, in a second-order transition scenario and in accordance with lattice and theoretical analysis. |
|---|