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Pion scattering poles and chiral symmetry restoration

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Fernández Fraile, Daniel and Gómez Nicola, Ángel and Herruzo, E. T. (2007) Pion scattering poles and chiral symmetry restoration. Physical review D, 76 (8). ISSN 1550-7998

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Official URL: http://dx.doi.org/10.1103/PhysRevD.76.085020


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http://journals.aps.org/Publisher


Abstract

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.


Item Type:Article
Additional Information:

© 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).

Uncontrolled Keywords:Perturbation-theory; Finite-temperature; Nuclear medium; Nonperturbative approach; Effective lagrangians; One-loop; Matter; Sigma; Transition; Meson
Subjects:Sciences > Physics > Physics-Mathematical models
Sciences > Physics > Mathematical physics
ID Code:30403
Deposited On:27 May 2015 10:09
Last Modified:10 Dec 2018 15:09

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