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

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We study the pion spectrum (and in particular taste-symmetry breaking within it) using HYP-smeared valence staggered fermions on the coarse and fine MILC lattices (which have asqtad staggered sea quarks). We focus on the dependence on…

High Energy Physics - Lattice · Physics 2010-01-21 David Adams , Taegil Bae , Hyung-Jin Kim , Jongjeong Kim , Kwangwoo Kim , Boram Yoon , Weonjong Lee , Chulwoo Jung , Stephen R. Sharpe

We calculate the B-parameters for operators arising in theories of new physics beyond the standard model (BSM) using HYP-smeared improved staggered fermions on the MILC asqtad lattices with N_f = 2+1 flavors. We use three different lattice…

We study the finite-volume effects in our calculation of $B_K$ using HYP-smeared improved staggered valence fermions. We calculate the predictions of both SU(3) and SU(2) staggered chiral perturbation theory at one-loop order. We compare…

High Energy Physics - Lattice · Physics 2010-02-23 Boram Yoon , Taegil Bae , Hyung-Jin Kim , Jangho Kim , Jongjeong Kim , Kwangwoo Kim , Weonjong Lee , Chulwoo Jung , Stephen R. Sharpe , Jisoo Yeo

We present results for the matrix elements of the additional $\Delta S=2$ operators that appear in models of physics beyond the Standard Model (BSM), expressed in terms of four BSM $B$-parameters. Combined with experimental results for…

We demonstrate the viability of improved staggered light quarks in studies of heavy-light systems. Our method for constructing heavy-light operators exploits the close relation between naive and staggered fermions. The new approach is…

High Energy Physics - Lattice · Physics 2009-11-07 Matthew Wingate , Junko Shigemitsu , Christine T. H. Davies , G. Peter Lepage , Howard D. Trottier

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 present results from an ongoing lattice study of the lowest lying charmonium and bottomonium level splittings using the Fermilab heavy quark formalism. Our objective is to test the performance of this action on MILC-collaboration…

High Energy Physics - Lattice · Physics 2010-11-05 T. Burch , C. E. DeTar , M. Di Pierro , A. X. El-Khadra , Steven Gottlieb , A. S. Kronfeld , L. Levkova , P. B. Mackenzie , J. Simone

We present an update for results on $B$-meson semileptonic decays using the highly improved staggered quark (HISQ) action for both valence and 2+1+1 sea quarks. The use of the highly improved action, combined with the MILC collaboration's…

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…

The MILC collaboration's simulations with improved staggered quarks are being extended with runs at a lattice spacing of 0.06 fm with quark masses down to one tenth the strange quark mass. We give a brief introduction to these new…

High Energy Physics - Lattice · Physics 2010-11-15 C. Bernard , C. Davies , C. DeTar , Steven Gottlieb , U. M. Heller , J. E. Hetrick , L. Levkova , J. Osborn , D. B. Renner , R. Sugar , D. Toussaint

The scaling corrections that affected previous staggered calculations of B_K have been proved to be reduced by using improved actions (HYP, Asqtad) in the quenched approximation. This improved behaviour allows us to perform a reliable…

High Energy Physics - Lattice · Physics 2010-01-18 E. Gamiz , S. Collins , C. T. H. Davies , J. Shigemitsu , M. Wingate

We discuss the impact of using one-loop matching on the calculation of $B_K$ using HYP-smeared improved staggered fermions. We give estimates of size of the truncation errors from the missing two-loop corrections.

High Energy Physics - Lattice · Physics 2010-02-23 Jangho Kim , Taegil Bae , Hyung-Jin Kim , Jongjeong Kim , Kwangwoo Kim , Boram Yoon , Weonjong Lee , Chulwoo Jung , Stephen R. Sharpe

We present an update of the MILC studies of the physics of light pseudoscalars using improved staggered fermions. New runs at lighter quark mass, as well as increased statistics for older sets, are enabling us to improve the results for…

We present results for $B_{(s)}$- and $D_{(s)}$-meson semileptonic decays from ongoing calculations by the Fermilab Lattice and MILC Collaborations. Our calculation employs the highly improved staggered quark (HISQ) action for both sea and…

We discuss the current status of our calculation of the physics of pi and K mesons using three dynamical flavors of improved staggered quarks. This year, we have a new ensemble with a lattice spacing of 0.06 fm and a light sea mass of 0.2…

High Energy Physics - Lattice · Physics 2010-11-15 C. Bernard , C. DeTar , Steven Gottlieb , U. M. Heller , J. E. Hetrick , L. Levkova , J. Osborn , D. Renner , R. Sugar , D. Toussaint

We extend our previous study of taste-symmetry breaking using HYP-smeared staggered fermions in two ways. First, we improve the statistics of a comparison of unimproved and HYP-smeared staggered fermions on quenched lattices with $a\approx…

High Energy Physics - Lattice · Physics 2008-11-26 Taegil Bae , David Adams , Chulwoo Jung , Hyung-Jin Kim , Jongjeong Kim , Kwangwoo Kim , Weonjong Lee , Stephen R. Sharpe

We calculate the leptonic decay constants of B_{(s)} and D_{(s)} mesons in lattice QCD using staggered light quarks and Fermilab bottom and charm quarks. We compute the heavy-light meson correlation functions on the MILC asqtad-improved…

We give a progress report on the calculation of B meson mixing matrix elements, focusing on contributions that could arise beyond the Standard Model. The calculation uses asqtad (light quark) and Fermilab (heavy quark) valence actions and…

High Energy Physics - Lattice · Physics 2011-05-18 C. Bouchard , A. X. El-Khadra , E. D. Freeland , E. Gamiz , A. S. Kronfeld

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 discuss finite volume errors in our calculations of $B_K$ using improved staggered fermions on the MILC asqtad lattices. Using GPUs, we are now able to extrapolate using next-to-leading order (NLO) staggered SU(2) chiral perturbation…

High Energy Physics - Lattice · Physics 2011-11-02 Jangho Kim , Hyung-Jin Kim , Weonjong Lee , Chulwoo Jung , Stephen R. Sharpe