Sigma-term physics in the perturbative chiral quark model
نویسنده
چکیده
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 πN sigma term σπN ≈ 45 MeV is in good agreement with the value deduced by Gasser, Leutwyler and Sainio using dispersionrelation techniques and exploiting the chiral symmetry constraints. PACS: 03.65.Pm, 11.10.Ef, 12.39.Fe, 12.39.Ki, 14.20.Dh
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X iv : h ep - p h / 03 11 27 5 v 1 2 1 N ov 2 00 3 Updated analysis of meson - nucleon sigma terms in the perturbative chiral quark model
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