We calculate, for the first time using unquenched lattice QCD, form factors for the rare decay B -> Kll in and beyond the Standard Model. Our lattice QCD calculation utilizes a nonrelativistic QCD formulation for the b valence quarks, the highly improved staggered quark formulation for the light valence quarks, and employs the MILC 2+1 asqtad ensembles. The form factor results, based on the z expansion, are valid over the full kinematic range of q^2. We construct the ratios f0/f+ and fT/f+, which are useful in constraining new physics and verifying effective theory form factor symmetry relations. We also discuss the calculation of Standard Model observables.
@article{arxiv.1306.2384,
title = {Rare decay B -> K ll form factors from lattice QCD},
author = {Chris Bouchard and G. Peter Lepage and Christopher Monahan and Heechang Na and Junko Shigemitsu},
journal= {arXiv preprint arXiv:1306.2384},
year = {2013}
}
Comments
30 pages, 23 figures; v2 adds a reference and fixes typos, results unchanged; v3 corrects a typo, updates references, makes minor changes in title and text, and is version published in Phys.Rev.D, results unchanged