SU(3)-breaking corrections to the hyperon vector coupling f1(0) in covariant baryon chiral perturbation theory

We calculate the SU(3)-breaking corrections to the hyperon vector coupling f1(0) up to O(p4) in covariant baryon chiral perturbation theory with dynamical octet and decuplet contributions. We find that the decuplet contributions are of similar or even larger size than the octet ones. Combining both, we predict positive SU(3)-breaking corrections to all the four independent f1(0)'s (assuming isospin symmetry), which are consistent, within uncertainties, with the latest results from large Nc fits, chiral quark models, and quenched lattice QCD calculations.