RT Journal Article
T1 Pion scattering poles and chiral symmetry restoration
A1 Fernández Fraile, Daniel
A1 Gómez Nicola, Ángel
A1 Herruzo, E. T.
AB Using unitarized chiral perturbation theory methods, we perform a detailed analysis of the π π scattering poles f_0(600) and ρ(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 f_0(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 π π bound states. We compare our results with several model approaches and discuss the experimental consequences, both in relativistic heavy ion collisions and in π  -> π π and γ -> π π reactions in nuclei.
PB Amer Physical Soc
SN 1550-7998
YR 2007
FD 2007-10
LK https://hdl.handle.net/20.500.14352/51388
UL https://hdl.handle.net/20.500.14352/51388
LA eng
NO © 2007 The American Physical Society.We are grateful to J. R. Peláez, G. Ríos and R. García Martín for very useful comments and discussions. We also acknowledge financial support from the Spanish research projects FPA2004-02602, FPA2005-02327, PR27/05- 13955-BSCH, UCM-CAM 910309 and from the F. P. I. programme (BES-2005-6726).
NO Spanish research Projects
NO UCM-CAM
DS Docta Complutense
RD 25 mar 2026