2007/07/31 by D. Fernandez-Fraile, D. Fernández-Fraile, Á. Gómez Nicola +2
Mathematics · Physics and Astronomy · #Amplitude #Chiral perturbation theory #Chiral symmetry #Geometry #High-Energy Particle Collisions Research #Mathematical physics #Mathematics #Particle physics #Particle physics theoretical and experimental studies #Physics #Pi #Pion #Quantum Chromodynamics and Particle Interactions #Quantum electrodynamics #Quantum mechanics #Quark #Scattering #Scattering amplitude #hep-ph
paper · pdf · doi:10.1103/physrevd.76.085020
published as Phys.Rev.D76:085020,2007 · 17 pages, 9 figures, final version to appear in Phys.Rev.D, added comments and references
arxiv created 2007/09/03 · openalex publication_date 2007/10/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Using unitarized chiral perturbation theory methods, we perform a detailed analysis of the \ensuremathπ\ensuremathπ scattering poles f0(600) and \ensuremathρ(770) behavior when medium effects such as temperature or density drive the system towards chiral symmetry restoration. In the analysis of real poles below threshold, we show that it is crucial to extend properly the unitarized amplitudes so that they match the perturbative Adler zeros. Our results do not show threshold enhancement effects at finite temperature in the f0(600) channel, which remains as a pole of broad nature. We also implement T=0 finite-density effects related to chiral symmetry restoration, by varying the pole position with the pion decay constant. Although this approach takes into account only a limited class of contributions, we reproduce the expected finite-density restoration behavior, which drives the poles towards the real axis, producing threshold enhancement and \ensuremathπ\ensuremathπ bound states. We compare our results with several model approaches and discuss the experimental consequences, both in relativistic heavy ion collisions and in \ensuremathπ\ensuremath→\ensuremathπ\ensuremathπ and \ensuremathγ\ensuremath→\ensuremathπ\ensuremathπ reactions in nuclei.