Related papers: B_K from improved staggered quarks
We study the improvement of staggered fermions using hypercubically smeared (HYP) links. We calculate the strange quark mass and the kaon B-parameter, $B_K$, in quenched QCD on a $16^3 \times 64$ lattice at $\beta=6.0$. We find…
The improved staggered quark action has enabled breakthrough calculations of QCD with three light dynamical quarks. The largest remaining $a^2$ scaling violations come from "taste-changing" interactions, which are significantly reduced over…
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 preliminary results for $B_K$ from the MILC ultrafine lattices, based on a partial ensemble of 305 configurations. We use HYP-smeared improved staggered valence quarks. The analysis is done using fitting forms based on both SU(2)…
Improved results for $B_K$ are discussed. Scaling corrections are argued to be of $O(a^2)$, leading to a reduction in the systematic error. For a kaon composed of degenerate quarks, the quenched result is ${\widehat{B}_K} = 0.825 \pm 0.027…
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…
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…
An unquenched calculation of the form factor for $B\to D^* l \nu$ is needed to improve the determination of $|V_{cb}|$. The MILC lattices, computed with a 2+1 improved staggered action for the light quarks, are well suited to this purpose.…
We present a calculation of the kaon $B$-parameter, $B_K$, using lattice QCD. We use improved staggered valence and sea fermions, the latter generated by the MILC collaboration with $N_f=2+1$ light flavors. To control discretization errors,…
We present progress on an ongoing calculation of the $B_s\to D_s^{(*)} l \nu$ form factors calculated on the $n_f=2+1+1$ MILC ensembles and using the Highly Improved Staggered Quark action for all valence quarks. We perform the calculation…
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…
The cost of dynamical quark simulations with improved staggered quarks is estimated based on current and planned running by the MILC collaboration. I find that a few 10s of Teraflop years should be sufficient to calculate down to a lattice…
We report on numerical experiments using deflation to compute quark propagators for the highly improved staggered quark (HISQ) action. The method is tested on HISQ gauge configurations, generated by the MILC collaboration, with lattice…
We calculate one-loop matching factors for bilinear operators composed of improved staggered fermions. We compare the results for different improvement schemes used in the recent literature, including the HYP action and an action close to…
We calculate the kaon mixing B-parameters for operators arising generically in theories of physics beyond the standard model. We use HYP-smeared improved staggered fermions on the $N_f = 2+1$ MILC asqtad lattices. Operator matching is done…
We present an update on the MILC Collaboration's light hadron spectrum calculation with two flavors of dynamical, staggered quarks. We present extrapolations of the nucleon to rho mass ratio to the continuum limit for fixed values of the pi…
We present an update of the Fermilab-MILC Collaboration's calculation of hadronic matrix elements for B^0-\bar{B^0} mixing. This work is a more extended analysis than our recent publication of the SU(3)-breaking ratio xi [arXiv:1205.7013].…
Calculations of B leptonic decays and B- bar B mixing using NRQCD heavy and Asqtad light valence quarks on the MILC dynamical configurations are described. Smearing has been implemented to substantially reduce the statistical errors of the…
We present results for one-loop perturbative matching factors using bilinear operators composed of improved staggered fermions, using unimproved (Wilson) and improved (Symanzik, Iwasaki, and DBW2) gluon actions. We consider two fermions…
We present preliminary results of matching factors of the four-fermion operators relevant to $B_K$, which are obtained using the non-perturbative renormalization (NPR) method in the RI-MOM scheme with HYP-smeared improved staggered…