EPJ

2024 Impact factor 2.8
EPJ A - Hadrons and Nuclei
Hadrons and Nuclei
Eur. Phys. J. A 3, 307-309

Short note

$\pi\pi$ S-wave phase shifts and non-perturbative chiral approach

N. Kaiser

Physik Department T39, Technische Universität München, D-85747 Garching, Germany

Received: 17 August 1998 / Revised version: 21 September 1998 Communicated by F. Lenz

Abstract
We extend a recent non-perturbative chiral approach to $\pi\pi$ S-wave scattering of Oller and Oset by including the couplings to the $\eta\eta$-channel. We find that the isospin-zero and isospin-two $\pi\pi$ S-wave phase shifts of the model deviate considerably from a recent solution of the Roy-equations. Including the couplings with the $\eta\eta$-channel does not improve the situation. In particular, no $\sigma$-meson like enhancement structure shows up in the Roy-equation solution. We also consider the $\pi\pi$-scattering lengths in this approach.

PACS
12.39.Fe Chiral lagrangians - 13.75.Lb Meson-meson interactions

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