Calculation of BSM Kaon B-parameters using Staggered Quarks

Abstract

We present updated results for kaon B-parameters for operators arising in models of new physics. We use HYP-smeared staggered quarks on the $N_f=2+1$ MILC asqtad lattices. During the last year we have added new ensembles, which has necessitated chiral-continuum fitting with more elaborate fitting functions. We have also corrected an error in a two-loop anomalous dimension used to evolve results between different scales. Our results for the beyond-the-Standard-Model B-parameters have total errors of $5-10$\%. We find that the discrepancy observed last year between our results and those of the RBC/UKQCD and ETM collaborations for some of the B-parameters has been reduced from $4-5\sigma$ to $2-3\sigma$.

Comments: 7 pages, 8 figures, Lattice 2014 proceeding