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PoS(LATTICE2016)286

Kaon semileptonic decays with $N_f=2+1+1$ HISQ fermions and physical light quark masses

E. Gamiz, A. Bazavov, C. Bernard, C. DeTar, D. Du, A.X. El-Khadra, E. Freeland, S. Gottlieb, U.M. Heller, J. Komijani, A. Kronfeld, J. Laiho, P.B. Mackenzie, E.T. Neil, T. Primer, J. Simone, R. Sugar, D. Toussaint, R. Van de Water, R. Zhou, Fermilab Lattice and MILC Collaborations

in 34th annual International Symposium on Lattice Field Theory

Contribution: pdf

Abstract

We discuss the reduction of errors in the calculation of vector the form factor for semileptonic kaon decays with HISQ fermions on the N_f=2+1+1 MILC configurations from increased statistics on some key ensembles, new data on ensembles with lattice spacings down to 0.042fm and the study of finite-volume effects within staggered ChPT. We also study the implications for the unitarity of the CKM matrix in the first row and for current tensions with leptonic determinations of |V_{us}|.