München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 18: Theorie

HK 18.6: Vortrag

Dienstag, 21. März 2006, 15:15–15:30, B

Baryon self energies in the chiral loop expansion — •Alexander Semke and M.F.M. Lutz — GSI, Plankstr. 1, 64291 Darmstadt

We compute the self energies of the baryon octet and decuplet states at the one-loop level applying the manifestly covariant chiral Lagrangian. It is demonstrated that expressions consistent with the expectation of power counting rules arise if the self energies are decomposed according to the Passarino-Veltman scheme supplemented by a minimal subtraction. This defines a partial summation of the chiral expansion. A finite renormalization required to install chiral power counting rules leads to the presence of an infrared renormalization scale. Good convergence properties for the chiral loop expansion of the baryon octet and decuplet masses are obtained for natural values of the infrared scale. A prediction for the strange-quark matrix element of the nucleon is made.