SU(3) breaking in hyperon transition vector form factors

Abstract

We present a calculation of the SU(3)-breaking corrections to the hyperon transition vector form factors to O(p[superscript 4]) in heavy-baryon chiral perturbation theory with finite-range regularization. Both octet and decuplet degrees of freedom are included. We formulate a chiral expansion at the kinematic point Q[superscript 2] = -(M[subscript B[subscript 1]]-M[subscript B[subscript 2]])[superscript 2], which can be conveniently accessed in lattice QCD. The two unknown low-energy constants at this point are constrained by lattice QCD simulation results for the Σ[superscript -] → n and Ξ[superscript 0] → Σ[superscript +] transition form factors. Hence, we determine lattice-informed values of f[subscript 1] at the physical point. This work constitutes progress toward the precise determination of |V[subscript us]| from hyperon semileptonic decays.