0000000000291103
AUTHOR
Jorge Martín Camalich
Octet-baryon axial-vector charges and SU(3)-breaking effects in the semileptonic hyperon decays
The octet-baryon axial-vector charges and the g(1)/f(1) ratios measured in the semileptonic hyperon decays are studied up to O(p(3)) using the covariant baryon chiral perturbation theory with explicit decuplet contributions. We clarify the role of different low-energy constants and find a good convergence for the chiral expansion of the axial-vector charges of the baryon octet, g(1)(0), with O(p(3)) corrections typically around 20% of the leading ones. This is a consequence of strong cancellations between different next-to-leading- order terms. We show that considering only nonanalytic terms is not enough and that analytic terms appearing at the same chiral order play an important role in t…
SU(3)-breaking corrections to the hyperon vector coupling f(1)(0) in covariant baryon chiral perturbation theory
We calculate the SU(3)-breaking corrections to the hyperon vector coupling f(1)(0) up to O(p(4)) 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 f(1)(0)'s (assuming isospin symmetry), which are consistent, within uncertainties, with the latest results from large N-c fits, chiral quark models, and quenched lattice QCD calculations.