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B-s -> Kl nu decay from lattice QCD
Journal article   Open access   Peer reviewed

B-s -> Kl nu decay from lattice QCD

A. Bazavov, C. Bernard, C. DeTar, Daping Du, A. X. El-Khadra, E. D. Freeland, E. Gamiz, Z. Gelzer, Steven Gottlieb, U. M. Heller, …
Physical review. D, Vol.100(3), 034501
08/01/2019
DOI: 10.1103/PhysRevD.100.034501
url
https://doi.org/10.1103/PhysRevD.100.034501View
Published (Version of record) Open Access

Abstract

We use lattice QCD to calculate the form factors f(+) (q(2)) and f(0) (q(2)) for the semileptonic decay B-s -> Kl nu. Our calculation uses six MILC asqtad 2 + 1 flavor gauge-field ensembles with three lattice spacings. At the smallest and largest lattice spacing the light-quark sea mass is set to 1/10 the strange-quark mass. At the intermediate lattice spacing, we use four values for the light-quark sea mass ranging from 1/5 to 1/20 of the strange-quark mass. We use the asqtad improved staggered action for the light valence quarks, and the clover action with the Fermilab interpolation for the heavy valence bottom quark. We use SU(2) hard-kaon heavy-meson rooted staggered chiral perturbation theory to take the chiral-continuum limit. A functional z expansion is used to extend the form factors to the full kinematic range. We present predictions for the differential decay rate for both Bs -> K mu nu and B-s -> K tau nu. We also present results for the forward-backward asymmetry, the lepton polarization asymmetry, ratios of the scalar and vector form factors for the decays B-s -> Kl nu and B-s -> D(s)l nu. Our results, together with future experimental measurements, can be used to determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-ub vertical bar.
Physical Sciences Physics Astronomy & Astrophysics Physics, Particles & Fields Science & Technology

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