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arXiv · 1508.06923

SU(3) breaking in hyperon transition vector form factors

P. E. Shanahan·A. N. Cooke·R. Horsley·Y. Nakamura·P. E. L. Rakow·G. Schierholz·A. W. Thomas·R. D. Young·J. M. Zanotti
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Abstract

We present a calculation of the SU(3)-breaking corrections to the hyperon transition vector form factors to $\mathcal{O}(p^4)$ in heavy baryon chiral perturbation theory with finite-range regularisation. Both octet and decuplet degrees of freedom are included. We formulate a chiral expansion at the kinematic point $Q^2=-(M_{B_1}-M_{B_2})^2$, 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 $Σ^-\rightarrow n$ and $Ξ^0\rightarrow Σ^+$ transition form factors. Hence we determine lattice-informed values of $f_1$ at the physical point. This work constitutes progress towards the precise determination of $|V_{us}|$ from hyperon semileptonic decays.

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P. E. Shanahan, A. N. Cooke, R. Horsley, Y. Nakamura, P. E. L. Rakow, G. Schierholz, A. W. Thomas, R. D. Young, J. M. Zanotti. 2015-08-27. SU(3) breaking in hyperon transition vector form factors. https://doi.org/10.1103/physrevd.92.074029

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