Hadronic matrix elements for B-mixing in the Standard Model and beyond

We use lattice QCD to calculate the B-mixing hadronic matrix elements for a basis of effective four-quark operators that spans the space of all possible contributions in, and beyond, the Standard Model. We present results for the SU(3)-breaking ratio and discuss our ongoing calculation of the mixing matrix elements, including the first calculation of the beyond the Standard Model matrix elements from unquenched lattice QCD.Comment: 3 pages, 1 figure. Proceedings for CIPANP 2012 - Eleventh Conference on the Intersections of Particle and Nuclear Physics, St. Petersburg FL, May 29 - June 3 201

Semileptonic form factors for B -> D*lv at nonzero recoil from 2+1-flavor lattice QCD

We present the first unquenched lattice-QCD calculation of the form factors for the decay B -> D*t nu at nonzero recoil. Our analysis includes 15 MILC ensembles with N-f = 2 + 1 flavors of asqtad sea quarks, with a strange quark mass close to its physical mass. The lattice spacings range from a asymptotic to 0.15 fm down to 0.045 fm, while the ratio between the light-and the strange-quark masses ranges from 0.05 to 0.4. The valence b and c quarks are treated using the Wilson-clover action with the Fermilab interpretation, whereas the light sector employs asqtad staggered fermions. We extrapolate our results to the physical point in the continuum limit using rooted staggered heavy-light meson chiral perturbation theory. Then we apply a model independent parametrization to extend the form factors to the full kinematic range. With this parametrization we perform a joint lattice-QCD/experiment fit using several experimental datasets to determine the CKM matrix element |V-cb|. We obtain |V-cb| = (38.40 +/- 0.68(th) +/- 0.34(exp) +/- 0.18(EM)) x 10(-3). The first error is theoretical, the second comes from experiment and the last one includes electromagnetic and electroweak uncertainties, with an overall chi(2)/dof = 126/84, which illustrates the tensions between the experimental data sets, and between theory and experiment. This result is in agreement with previous exclusive determinations, but the tension with the inclusive determination remains. Finally, we integrate the differential decay rate obtained solely from lattice data to predict R(D*) = 0.265 +/- 0.013, which confirms the current tension between theory and experiment.United States Department of Energy (DOE)National Science Foundation's Teragrid/XSEDE ProgramUnited States Department of Energy (DOE) DE-FG02-13ER41976 DE-SC0009998 DE-SC0010120 DE-SC0015655National Science Foundation (NSF) PHY17-19626 PHY14-17805 SRA (Spain) P18-FR-4314Consejeria de Economia, Innovacion, Ciencia y Empleo, Junta de Andalucia (Spain) P18-FR-4314 A-FQM-467-UGR18Fermilab Distinguished Scholars Progra

Measurement of B(D+ -> mu+ nu) and the pseudoscalar decay constant f_D at CLEO

The analysis of 60 1/pb data collected on the psi(3770) resonance with the CLEO-c detector has produced the first statistically significant signal for D+ -> mu+ nu decay and led to the measurement of the decay branching fraction B(D+ -> mu+ nu) = (3.5 +- 1.4 +- 0.6) x 10-4 and the pseudoscalar decay constant f_D = (202 +- 41 +- 17) MeV.Comment: Talk presented at the 1st Meeting of the APS Topical Group on Hadronic Physics (Fermilab, Oct. 24-26, 2004). LaTeX 4 pages, 2 figure

Mass of the B_c Meson in Three-Flavor Lattice QCD

We use lattice QCD to predict the mass of the $B_c$ meson. We use the MILC Collaboration's ensembles of lattice gauge fields, which have a quark sea with two flavors much lighter than a third. Our final result is $m_{B_c}=6304\pm12^{+18}_{- 0} MeV$. The first error bar is a sum in quadrature of statistical and systematic uncertainties, and the second is an estimate of heavy-quark discretization effects.Comment: 4 pages, 3 figures; shorten to fit in PRL; published versio

B Mixing in the Standard Model and Beyond: Lattice QCD

We give a brief overview and progress report on our lattice QCD calculation of neutral B mixing hadronic matrix elements needed for Standard Model and Beyond the Standard Model physics. Reference [1] contains more details and results.Comment: 3 pages, 0 figures, Proceedings of the 19th Particles and Nuclei International Conference (PANIC11), Cambridge, MA, U.S.A., July 201

Heavy-Quark Masses from the Fermilab Method in Three-Flavor Lattice QCD

We report on heavy quark mass calculations using Fermilab heavy quarks. Lattice calculations of heavy-strange meson masses are combined with one-loop (automated) lattice perturbation theory to arrive at the quark mass. Mesons are constructed from Fermilab heavy quarks and staggered light quarks. We use the MILC ensembles at three lattice spacings and sea quark mass ratios of $m_{\rm u,d} / m_{\rm s} = 0.1$ to 0.4. Preliminary results for the bottom quark are given in the potential subtracted scheme

Quantum chromodynamics with advanced computing

We survey results in lattice quantum chromodynamics from groups in the USQCD Collaboration. The main focus is on physics, but many aspects of the discussion are aimed at an audience of computational physicists.Comment: 17 pp. Featured presentation at Scientific Discovery with Advanced Computing, July 13-17, Seattl

Bs→KℓνB_s \to K \ell\nu form factors with 2+1 flavors

Using the MILC 2+1 flavor asqtad quark action ensembles, we are calculating the form factors $f_0$ and $f_+$ for the semileptonic $B_s \rightarrow K \ell\nu$ decay. A total of six ensembles with lattice spacing from $\approx0.12$ to 0.06 fm are being used. At the coarsest and finest lattice spacings, the light quark mass $m'_l$ is one-tenth the strange quark mass $m'_s$. At the intermediate lattice spacing, the ratio $m'_l/m'_s$ ranges from 0.05 to 0.2. The valence $b$ quark is treated using the Sheikholeslami-Wohlert Wilson-clover action with the Fermilab interpretation. The other valence quarks use the asqtad action. When combined with (future) measurements from the LHCb and Belle II experiments, these calculations will provide an alternate determination of the CKM matrix element $|V_{ub}|$.Comment: 8 pages, 6 figures, to appear in the Proceedings of Lattice 2017, June 18-24, Granada, Spai