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Related papers: Calculation of BSM Kaon B-parameters using Stagger…

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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 preliminary results for $B_K$ calculated using improved staggered fermions with a mixed action (HYP-smeared staggered valence quarks and AsqTad staggered sea quarks). We investigate the effect of non-degenerate quarks on $B_K$…

High Energy Physics - Lattice · Physics 2008-11-26 Jongjeong Kim , Taegil Bae , Weonjong Lee , Stephen R. Sharpe

We investigate the use of two kinds of staggered fermion operators, smeared and unsmeared. The smeared operators extend over a $4^4$ hypercube, and tend to have smaller perturbative corrections than the corresponding unsmeared operators. We…

High Energy Physics - Lattice · Physics 2009-10-30 Greg Kilcup , Rajan Gupta , Stephen Sharpe

We give an update on simulation results for the decay constants f_B, f_{B_s}, f_D and f_{D_s}. These decay constants are important for precision tests of the standard model, in particular entering as inputs to the global CKM unitarity…

We present a new determination of the B and B_s meson decay constants using NRQCD b-quarks, HISQ light and strange valence quarks and the MILC collaboration N_f=2+1 lattices. The new calculations improve on HPQCD's earlier work with NRQCD…

High Energy Physics - Lattice · Physics 2012-08-27 Heechang Na , Chris J. Monahan , Christine T. H. Davies , Ron Horgan , G. Peter Lepage , Junko Shigemitsu

We calculate the $B_B$ parameter, relevant for $\overline{B}^0$--$B^0$ mixing, from a lattice gauge theory simulation using the static approximation for the heavy quark and the Wilson action for the light quark and gauge fields. Improved…

High Energy Physics - Lattice · Physics 2008-11-26 Joseph Christensen , Terrence Draper , Craig McNeile

A lattice QCD calculation of the kaon $B$ parameter $B_K$ is carried out with the Wilson quark action in the quenched approximation at $\beta=6/g^2=5.9-6.5$. The mixing problem of the $\Delta s=2$ four-quark operators is solved…

High Energy Physics - Lattice · Physics 2009-10-31 S. Aoki , M. Fukugita , S. Hashimoto , N. Ishizuka , Y. Iwasaki , K. Kanaya , Y. Kuramashi , M. Okawa , A. Ukawa , T. Yoshie

We review recent results for B_d and B_s mixing parameters using MILC N_f=2+1 lattices, NRQCD b-quarks and AsqTad light quarks. Latest numbers for decay constants f_B and f_{B_s} are also presented. Combining our lattice results with…

High Energy Physics - Lattice · Physics 2010-11-05 J. Shigemitsu , C. T. H. Davies , E. Follana , E. Gamiz , E. Gregory , G. P. Lepage , H. Na , M. Wingate

I calculate the kaon B-parameter with a lattice simulation in quenched approximation. The lattice simulation uses an action possessing exact lattice chiral symmetry, an overlap action. Computations are performed at two lattice spacings,…

High Energy Physics - Lattice · Physics 2008-11-26 Thomas DeGrand

We present an update of the Fermilab Lattice and MILC Collaborations project to compute the form factors for semileptonic $B_{(s)}$-meson decays. Our calculation uses the highly improved staggered quark (HISQ) action for sea and valence…

We compute Z-factors for general staggered bilinears on fine (a \approx 0.09 fm) MILC ensembles using both asqtad and HYP-smeared valence actions, comparing the results to the predictions of one-loop perturbation theory. This is an…

High Energy Physics - Lattice · Physics 2012-12-04 Andrew T. Lytle , Stephen R. Sharpe

I calculate, at one loop in staggered chiral perturbation theory, the matrix elements of the complete set of five local operators that may contribute to B mixing both in the Standard Model and in beyond-the-Standard-Model theories. Lattice…

High Energy Physics - Lattice · Physics 2013-06-12 C. Bernard

We report on a calculation of $B_c$ ground state and radial excitation energies, obtained from heavy-charm highly improved staggered quark (HISQ) correlators computed on MILC gauge ensembles, with lattice spacings down to $a=0.044$ fm.…

High Energy Physics - Lattice · Physics 2018-11-26 Andrew Lytle , Brian Colquhoun , Christine Davies , Jonna Koponen

We compute non-perturbatively the B-parameters of the complete basis of four-fermion operators needed to study the Kaon oscillations in the SM and in its supersymmetric extension. We perform numerical simulations with two dynamical…

High Energy Physics - Lattice · Physics 2010-02-10 V. Bertone , P. Dimopoulos , R. Frezzotti , V. Gimenez , V. Lubicz , F. Mescia , D. Palao , M. Papinutto , G. C. Rossi , S. Simula , A. Vladikas

We discuss the matching procedure for heavy-light 4-quark operators using the Fermilab method for heavy quarks and staggered fermions for light quarks. These ingredients enable us to construct the continuum-limit operator needed to…

High Energy Physics - Lattice · Physics 2010-11-05 Richard Todd Evans , Elvira Gamiz , Aida El-Khadra , Andreas Kronfeld

We study $B_d$ and $B_s$ mixing in unquenched lattice QCD employing the MILC collaboration gauge configurations that include u, d, and s sea quarks based on the improved staggered quark (AsqTad) action and a highly improved gluon action. We…

High Energy Physics - Lattice · Physics 2009-09-30 Elvira Gámiz , Christine T. H. Davies , G. Peter Lepage , Junko Shigemitsu , Matthew Wingate

We present results for matching factors for staggered four-fermion operators constructed using HYP-smeared fat links both in the action and the operators. We use perturbation theory to calculate the matching factors and work to one-loop…

High Energy Physics - Lattice · Physics 2011-03-10 Jongjeong Kim , Weonjong Lee , Stephen R. Sharpe

These lectures review some of the progress made in the quantitative understanding of B decays. The emphasis here is on applications of QCD using perturbative and non-perturbative techniques. In some cases, however, phenomenological models…

High Energy Physics - Phenomenology · Physics 2011-04-15 A. Ali

We compute pseudoscalar meson masses and decay constants using staggered quarks on lattices with three flavors of sea quarks and lattice spacings $\approx 0.12$ fm and $\approx 0.09$ fm. We fit partially quenched results to ``staggered…

A recent numerical lattice calculation of the kaon mixing matrix elements of general $\Delta S=2$ four-fermion operators using staggered fermions relied on two auxiliary theoretical calculations. Here we describe the methodology and present…

High Energy Physics - Lattice · Physics 2014-07-16 Jongjeong Kim , Weonjong Lee , Jaehoon Leem , Stephen R. Sharpe , Boram Yoon