Tübingen 2003 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 13: Poster-Sitzung: Theorie

HK 13.8: Poster

Dienstag, 18. März 2003, 13:30–15:30, Foyer

Baryon magnetic moments and sigma terms in lattice-regularized chiral perturbation theory — •Buḡra Borasoy¹, Randy Lewis², and Pierre Ouimet^1,2 — ¹Physik Department der Technischen Universität München,Garching, Germany — ²Department of Physics, University of Regina, Regina, Canada

An SU(3) chiral Lagrangian for the lightest decuplet of baryons is constructed on a discrete lattice of spacetime points, and is added to an existing lattice Lagrangian for the lightest octets of mesons and baryons. A nonzero lattice spacing renders all loop integrations finite, and the continuum limit of any physical observable is identical to the result obtained from dimensional regularization. Chiral symmetry and gauge invariance are preserved even at nonzero lattice spacing. We discuss the non-renormalization of a conserved vector current, the magnetic moments of octet baryons, and the π N and KN sigma terms that relate to the nucleon’s strangeness content. The quantitative difference between physics at a nonzero lattice spacing and physics in the continuum limit is easily computed, and it represents an expectation for the size of discretization errors in corresponding lattice QCD simulations.

Work supported in part by the Deutsche Forschungsgemeinschaft and the Natural Sciences and Engineering Research Council of Canada.