Münster 2002 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 9: Poster Session: Theory

HK 9.7: Poster

Dienstag, 12. März 2002, 10:30–12:45, Foyer Chemie

Baryon chiral perturbation theory with a cutoff regularization: Inclusion of decuplet states — •Buḡra Borasoy¹, Barry Holstein², Randy Lewis³, and Pierre Ouimet³ — ¹Physik Department, Technische Universität München — ²University Of Massachusetts, Amherst, USA — ³University of Regina, Regina, Canada

In SU(3) chiral perturbation theory short distance effects, arising from the propagation of Goldstone bosons over distances smaller than a typical hadronic size, are model-dependent and can lead to a lack of convergence in the SU(3) chiral expansion if they are included in loop diagrams. Such effects can be removed in a chirally consistent fashion by use of a cutoff ameliorating problems which have arisen in previous calculations due to large loop effects. In this investigation, we employ cutoff regularization and focus on the inclusion of decuplet states which may yield significant contributions since the mass difference between the nucleon and decuplet is less than twice the pion mass and octet and decuplet states become even degenerate in the large N_c limit. We discuss the octet baryon masses, axial couplings, s-wave hyperon decay, and magnetic moments taking contributions from internal decuplet states into account. The realistic treatment of chiral baryon corrections is just what is needed in order to extrapolate state of the art lattice calculations, which are done for quark masses (and therefore pion masses) considerably heavier than the values given experimentally, down to realistic values.

Work supported in part by the DFG.