Jorge Martin Camalich

University of Valencia

Properties of hyperons in covariant chiral perturbation theory

We present some recent progress on the understanding of the SU(3)-breaking corrections to different observables of the lowest-lying octet-and decuplet-baryons using relativistic chiral perturbation theory (ChPT). For the baryon-octet magnetic moments we improve the Coleman-Glashow description when we include the SU(3)-breaking chiral corrections and by fitting the two same free parameters or low-energy constants. We discuss in detail the effects of the decuplet-resonances. We then show the predictions of this approach when it is extended to describe the electromagnetic static properties of the decuplet resonances. In particular, we predict a dipole magnetic moments for the Δ+ and Δ++ compatible with the current experimental data. Finally we would like to present the results of a fourth order calculation within this formalism of the vector hyperon decay charge f1(0) , which is essential to extract the Cabibbo-Kobayashi-Maskawa matrix element Vus from hyperon decay data.

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