Köln 2004 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 26: Theory IV

HK 26.3: Talk

Wednesday, March 10, 2004, 11:30–11:45, D

Chiral Extrapolations and Non-Analytic Terms — •Dominik Nickel, Michael Buballa, and Jochen Wambach — IKP, TU Darmstadt, Germany

Since lattice QCD is so far limited to unrealistically large quark masses (corresponding to pion masses of 400 MeV or more), the resulting observables must be extrapolated to the physical point. Usually this is done by simple polynomial fits to the data. It has also been suggested to employ chiral models for the extrapolations in order to ensure the correct non-analytic behavior in the chiral limit. In this talk, we investigate the relevance of the leading non-analytic (LNA) terms and present results obtained with the 1/N_c-corrected NJL model. It will be shown that the LNA terms, which are also formally reproduced correctly by the NJL model, give a very poor description of the m_π dependence of the hadron masses, mainly because of the implicit definition of the masses as the poles of the dressed propagators.