1306.2384 (Chris Bouchard et al.)

The rare decay B -> K ll form factors from lattice QCD    [PDF]

Chris Bouchard, G. Peter Lepage, Christopher Monahan, Heechang Na, Junko Shigemitsu

We calculate, for the first time using unquenched lattice QCD, form factors for the rare decay B -> K ll in and beyond the Standard Model. Our lattice QCD calculation utilizes NRQCD b and HISQ light valence quarks on 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 f_0/f_+ and f_T/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.

View original: http://arxiv.org/abs/1306.2384