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Sigma-term physics in the perturbative chiral quark model

V. E. Lyubovitskij·Th. Gutsche·Amand Faessler·E. G. Drukarev
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Abstract

We apply the perturbative chiral quark model (PCQM) at one loop to analyse meson-baryon sigma-terms. Analytic expressions for these quantities are obtained in terms of fundamental parameters of low-energy pion-nucleon physics (weak pion decay constant, axial nucleon coupling, strong pion-nucleon form factor) and of only one model parameter (radius of the nucleonic three-quark core). Our result for the piN sigma term of about 45 MeV is in good agreement with the value deduced by Gasser, Leutwyler and Sainio using dispersion-relation techniques and exploiting the chiral symmetry constraints.

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V. E. Lyubovitskij, Th. Gutsche, Amand Faessler, E. G. Drukarev. 2000-12-08. Sigma-term physics in the perturbative chiral quark model. https://doi.org/10.1103/physrevd.63.054026

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