Nonperturbative ``Lattice Perturbation Theory''

We discuss a program for replacing standard perturbative methods with Monte Carlo simulations in short distance lattice gauge theory calculations.Comment: 3 pages, uuencoded Latex file, two embedded figures and .sty file include

Moving NRQCD for B Form Factors at High Recoil

We derive the continuum and lattice tree-level moving NRQCD (mNRQCD) through order 1/m^2. mNRQCD is a generalization of NRQCD for dealing with hadrons with nonzero velocity u_mu. The quark's total momentum is written as P^mu=Mu^mu+k^mu where k^mu << Mu^mu is discretized and Mu^mu is treated exactly. Radiative corrections to couplings on the lattice are discussed. mNRQCD is particularly useful for calculating B->pi and B->D form factors since errors are similar at low and high recoil.Comment: 3 pages, 1 figure, Lattice2002(heavyquark

B_s Mesons using Staggered Light Quarks

Last year we proposed using staggered fermions as the light quarks, combined with nonrelativistic heavy quarks, in simulations of heavy-light mesons. A first round of tests which focuses on the B_s meson has been completed using quenched lattices, and results are presented here for the kinetic B_s mass, the B_s^* - B_s splitting, and f_{B_s}. The next project, already underway, is to compute the B and B_s decay constants and spectra on the n_f = 2+1 and 3 MILC lattices. We report on progress with one set of these configurations.Comment: Talk presented by M.W. at Lattice2002(heavyquark

Expected Precision of Higgs Boson Partial Widths within the Standard Model

We discuss the sources of uncertainty in calculations of the partial widths of the Higgs boson within the Standard Model. The uncertainties come from two sources: the truncation of perturbation theory and the uncertainties in input parameters. We review the current status of perturbative calculations and note that these are already reaching the parts-per-mil level of accuracy for the major decay modes. The main sources of uncertainty will then come from the parametric dependences on alpha_s, m_b, and m_c. Knowledge of these parameters is systematically improvable through lattice gauge theory calculations. We estimate the precision that lattice QCD will achieve in the next decade and the corresponding precision of the Standard Model predictions for Higgs boson partial widths.Comment: 20 pages, 1 figure; v2: minor typo correction

D→KlνD \rightarrow Kl{\nu} semileptonic decay using lattice QCD with HISQ at physical pion masses

The quark flavor sector of the Standard Model is a fertile ground to look for new physics effects through a unitarity test of the Cabbibo-Kobayashi-Maskawa (CKM) matrix. We present a lattice QCD calculation of the scalar and the vector form factors (over a large $q^2$ region including $q^2 = 0$) associated with the $D \rightarrow Kl{\nu}$ semi-leptonic decay. This calculation will then allow us to determine the central CKM matrix element, $V_{cs}$ in the Standard Model, by comparing the lattice QCD results for the form factors and the experimental decay rate. This form factor calculation has been performed on the $N_f =2+1+1$ MILC HISQ ensembles with the physical light quark masses.Comment: Proceedings for the 35th International Symposium on Lattice Field Theory (Lattice 2017), 8 pages, 5 figure