RT Journal Article
T1 Large-N pion scattering at finite temperature: The f(0)(500) and chiral restoration
A1 Cortés, Santiago
A1 Gómez Nicola, Ángel
A1 Morales, John
AB 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.
PB Amer Physical Soc
SN 1550-7998
YR 2016
FD 2016-02-05
LK https://hdl.handle.net/20.500.14352/23197
UL https://hdl.handle.net/20.500.14352/23197
LA eng
NO © 2016 American Physical Society.Work partially supported by research Contracts No. FPA2011-27853-C02-02 (Spanish “Ministerio de Ciencia e Innovación”), No. FPA2014-53375-C2-2-P (Spanish “Ministerio de Economía y Competitividad”). We also acknowledge the support of the EU FP7 HadronPhysics3 project, the Spanish Hadron Excellence Network (Spanish “Ministerio de Economía y Competitividad” Contract No. FIS2014-57026-REDT) and the UCM-Banco de Santander Contract No. GR3/14 910309. S. C. thanks Professor José Rolando Roldán and the High Energy Physics group of Universidad de los Andes. In particular, he acknowledges financial support  from that University to perform a research stay at Universidad Complutense during which this work was partially accomplished. We are also grateful to José Ramón Peláez and Jacobo Ruiz de Elvira for useful comments and for providing us with their parametrization values for the phase shift.
NO Unión Europea. FP7
NO Ministerio de Ciencia e Innovación (MICINN)
NO Ministerio de Economía y Competitividad (MINECO)
NO UCM-Banco de Santander
NO Universidad Complutense de Madrid
DS Docta Complutense
RD 8 abr 2025