Related papers: B_K from improved staggered quarks

In HISQ simulations by the MILC and Fermilab Lattice collaborations, both the light quarks and the charm quark are staggered. We extend staggered chiral perturbation theory (\schpt) to include such all-staggered heavy-light mesons. We…

We investigate light hadron spectroscopy with an improved quenched staggered quark action. We compare the results obtained with an improved gauge plus an improved quark action, an improved gauge plus standard quark action, and the standard…

We describe an implementation of the Rational Hybrid Monte Carlo (RHMC) algorithm for dynamical computations with two flavours of staggered quarks. We discuss several variants of the method, the performance and possible sources of error for…

The status of b-bbar and c-cbar calculations, numerical and analytic, are reviewed. The extraction of alpha_s and quark masses from spectrum calculations is discussed. The NRQCD and Improved Heavy Wilson formulations of heavy quarks are…

We resolve contradictions in the literature concerning the origins and size of unphysical flavor-changing strong interactions generated by the staggered-quark discretization of QCD. We show that the leading contributions are tree-level in…

We calculate the kaon B-parameter, B_K, to next-to-leading order in staggered chiral perturbation theory. We extend the usual power counting to include the effects of using perturbative (rather than non-perturbative) matching factors. Taste…

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…

We report on the status of the Fermilab-MILC calculation of the form factor f_+^{K pi}(0), needed to extract the CKM matrix element |V_{us}| from experimental data on K semileptonic decays. The HISQ formulation is used in the simulations…

We present preliminary results for the D_s meson spectrum and decay constants in unquenched lattice QCD. Simulations are carried out with 2+1 dynamical quarks using gauge configurations generated by the MILC collaboration. We use the…

We present determinations of the B meson decay constant f_B and of the ratio f_{B_s}/f_B using the MILC collaboration unquenched gauge configurations which include three flavors of light sea quarks. The mass of one of the sea quarks is kept…

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 report calculations of B_K using two flavours of dynamical clover-improved Wilson lattice fermions and look for dependence on the dynamical quark mass at fixed lattice spacing. We see some evidence for dynamical quark effects. In…

We describe the current status of the MILC collaboration computation of $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios. Progress over the past year includes: better statistics and plateaus at $\beta=6.52$ (quenched), $\beta=5.6$…

We present a calculation of the form factor for B -> D* l nu using a 2+1 improved staggered action for the light quarks (on the MILC configurations), and the Fermilab action for the heavy quarks. The form factor is computed at zero recoil…

The MILC Collaboration has been producing ensembles of lattice configurations with three dynamical flavors for the past few years. There are now results for three lattice spacings for a variety of light and strange quark masses, ranging…

We introduce a new class of actions for staggered quarks in lattice QCD which significantly reduce flavour symmetry violations in the pion mass spectrum. An action introduced by the MILC collaboration for the same purpose is seen to be a…

We calculate the neutral kaon mixing parameter B_K in unquenched lattice QCD using asqtad-improved staggered sea quarks and domain-wall valence quarks. We use the "2+1" flavor gauge configurations generated by the MILC Collaboration, 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…

We have computed $ B_K $, using two different methods with staggered fermions on a $ 16^3 \times 40 $ lattice at $ \beta = 5.7 $ with two dynamical flavors of a mass 0.01. % Using an improved wall source method, we have studied a series of…

We calculate form factors relevant for rare B decays using moving-NRQCD for the b quark and the AsqTad action for the light quarks. Moving NRQCD allows us to work directly with the physical b quark mass and go to higher recoil momentum…