paper

Neutral B-meson mixing parameters in and beyond the SM with 2+1 flavor lattice QCD

arXiv:1412.5097

Abstract

We report on the status of our calculation of the hadronic matrix elements for neutral $B$ -meson mixing with asqtad sea and valence light quarks and using the Wilson clover action with the Fermilab interpretation for the $b$ quark. We calculate the matrix elements of all five local operators that contribute to neutral $B$ -meson mixing both in and beyond the Standard Model. We use MILC ensembles with $N_{f} = 2 + 1$ dynamical flavors at four different lattice spacings in the range $a \approx 0.045$ -- $0.12$ ~fm, and with light sea-quark masses as low as 0.05 times the physical strange quark mass. We perform a combined chiral-continuum extrapolation including the so-called wrong-spin contributions in simultaneous fits to the matrix elements of the five operators. We present a complete systematic error budget and conclude with an outlook for obtaining final results from this analysis.

7 pages, 4 figures, presented at the 32nd International Symposium on Lattice Field Theory (Lattice 2014), 23-28 June, 2014, Columbia University, New York, NY