We present one-loop matching coefficients between continuum and lattice QCD for the heavy-light four-fermion operators relevant for neutral B meson mixing both within and beyond the Standard Model. For the lattice theory we use nonrelativistic QCD (NRQCD) to describe b quarks and improved staggered fermions (AsqTad) for light quarks. The gauge action is the tree-level Symanzik improved gauge action. Matching to full QCD is carried out through order alpha_s, Lambda_{QCD}/M_b, and alpha_s/(aM_b).
@article{arxiv.0804.1557,
title = {Four Fermion Operator Matching with NRQCD Heavy and AsqTad Light Quarks},
author = {Elvira Gamiz and Junko Shigemitsu and Howard Trottier},
journal= {arXiv preprint arXiv:0804.1557},
year = {2008}
}