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Related papers: Recent progress in calculation of $B_K$ using stag…

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I present first results from an in-progress calculation of B_K in quenched approximation using overlap fermions. My particular implementation of the overlap uses a kernel with nearest and next-nearest neighbor interactions and HYP-blocked…

High Energy Physics - Lattice · Physics 2015-06-25 Thomas DeGrand

We present a lattice investigation of the heavy-light meson decay constants using Wilson light quarks and NRQCD heavy quarks, partially including the effects of dynamical sea quarks. We calculate the pseudoscalar and vector decay constants…

High Energy Physics - Lattice · Physics 2010-01-18 S. Collins , U. M. Heller , J. Sloan , J. Shigemitsu , A. Ali Khan , C. T. H. Davies

We report on the ALPHA Collaboration's lattice B-physics programme based on N_f=2 O(a) improved Wilson fermions and HQET, including all NLO effects in the inverse heavy quark mass, as well as non-perturbative renormalization and matching,…

Mass-split systems based on a conformal infrared fixed point provide a low-energy effective description of beyond the standard model systems with large scale separation. We report results of exploratory investigations with four light and…

High Energy Physics - Lattice · Physics 2018-04-18 Anna Hasenfratz , Claudio Rebbi , Oliver Witzel

We present an update on the analysis of semileptonic $B\rightarrow D^{(*)}$ decays at non-zero recoil. Our computation employs $2 + 1 + 1$ FNAL-MILC ensembles with highly improved staggered quark (HISQ) action for sea and light valence…

We perform a precise calculation of the mass of the B_c meson using unquenched configurations from the MILC collaboration including 2+1 flavours of improved staggered quarks. Lattice NRQCD and the Fermilab formalism are used to describe the…

High Energy Physics - Lattice · Physics 2011-03-23 I. F. Allison , C. T. H Davies , A. Gray , A. S. Kronfeld , P. B. Mackenzie , J. N. Simone

We extend the picture of $B$-meson decay constants obtained in lattice QCD beyond those of the $B$, $B_s$ and $B_c$ to give the first full lattice QCD results for the $B^*$, $B^*_s$ and $B^*_c$. We use improved NonRelativistic QCD for the…

High Energy Physics - Lattice · Physics 2015-07-01 B. Colquhoun , C. T. H. Davies , R. J. Dowdall , J. Kettle , J. Koponen , G. P. Lepage , A. T. Lytle

We introduce a lattice fermion-Higgs model with one component `reduced staggered' fermions. In order to use the fermion field as efficiently as possible we couple the two {\em staggered} flavors to the O(4) Higgs field leading to a model…

High Energy Physics - Lattice · Physics 2009-10-22 Wolfgang Bock , Jan Smit , Jeroen C. Vink

We report on results from three spectrum calculations with staggered quarks: 1) a quenched calculation with the standard action for the gluons and quarks; 2) a quenched calculation with improved actions for both the gluons and quarks; and…

The results of an extensive study of B-meson properties in quenched lattice QCD are presented. The studies are carried out in the static quark limit where the b-quark is taken to be infinitely massive. Our computations rely on a multistate…

High Energy Physics - Lattice · Physics 2011-02-01 A. Duncan , E. Eichten , J. Flynn , B. Hill , G. Hockney , H. Thacker

Accurately calculating the mass of flavor-singlet meson states from numerical lattice simulations is an important milestone for lattice QCD. Careful measurement of the full pseudoscalar flavor-singlet propagator is also a crucial step in…

High Energy Physics - Lattice · Physics 2008-11-26 Eric B. Gregory , Alan Irving , Chris M. Richards , Craig McNeile , Alistair Hart

We compute the form factors for the $B \to Kl^+l^-$ semileptonic decay process in lattice QCD using gauge-field ensembles with 2+1 flavors of sea quark, generated by the MILC Collaboration. The ensembles span lattice spacings from 0.12 to…

Semileptonic, B --> pi l,nu, decays are studied on the MILC dynamical configurations using NRQCD heavy and Asqtad light quarks. We work with light valence quark masses ranging between m_s and m_s/8. Preliminary simple linear chiral…

High Energy Physics - Lattice · Physics 2009-11-10 J. Shigemitsu , C. T. H. Davies , A. Dougall , K. Foley , E. Gamiz , A. Gray , E. Gulez , G. P. Lepage , M. Wingate

The Asqtad improved staggered fermion formalism has been a valuable tool in successfully calculating the non-singlet parts of the hadronic spectrum. We are engaged in a project to calculate the spectrum of the pseudoscalar singlet mesons…

High Energy Physics - Lattice · Physics 2008-11-26 Eric B. Gregory , Alan C. Irving , Craig McNeile , Christopher M. Richards

The determinations of $|V_{\rm ub}|$ from the exclusive branching ratios of $B\to \tau \nu$ and $B \to \pi l \nu$ tend to show a tension at the level of $3\sigma$ \cite{Beringer:1900zz}. On the theoretical side they depend on the lattice…

High Energy Physics - Lattice · Physics 2012-10-15 Felix Bahr , Fabio Bernardoni , John Bulava , Alberto Ramos , Hubert Simma , Rainer Sommer

We present a lattice-QCD calculation of the hadronic form factors for $B$-meson semileptonic decays computed using the highly improved staggered quark action for both valence and sea quarks on the MILC collaborations 2+1+1-flavor ensembles…

We report on recent progress in employing the Highly Improved Staggered Quark (HISQ) action introduced by the HPQCD/UKQCD collaboration in simulations with dynamical fermions. The HISQ action is an order $a^2$ Symanzik-improved action with…

High Energy Physics - Lattice · Physics 2010-01-21 A. Bazavov , C. Bernard , C. DeTar , W. Freeman , Steven Gottlieb , U. M. Heller , J. E. Hetrick , J. Laiho , L. Levkova , J. Osborn , R. Sugar , D. Toussaint

We discuss the reduction of errors in the calculation of the form factor $f_+^{K \pi}(0)$ with HISQ fermions on the $N_f=2+1+1$ MILC configurations from increased statistics on some key ensembles, new data on ensembles with lattice spacings…

We deliver a lattice study of $\rho$ resonance parameters with p-wave $\pi\pi$ scattering phases, which are extracted by finite-size methods at one center-of-mass frame and four moving frames for six MILC lattice ensembles with pion masses…

High Energy Physics - Lattice · Physics 2016-08-29 Ziwen Fu , Lingyun Wang

During the past year the MILC Collaboration has continued its study of heavy-light meson decay constants with three dynamical quarks. Calculations have been extended to a second lattice spacing of about 0.09 fm. At this lattice spacing,…

High Energy Physics - Lattice · Physics 2008-11-26 MILC Collaboration , C. Bernard , T. Burch , S. Datta , C. DeTar , Steven Gottlieb , E. Gregory , Urs M. Heller , R. Sugar , D. Toussaint