Related papers: $B_K$ from improved staggered fermions using SU(3)…
Consideration of the analytical properties of pion-induced baryon self-energies leads to new functional forms for the extrapolation of light baryon masses. These functional forms reproduce the leading non-analytic behavior of chiral…
We present our investigation of SU(2) gauge theory with 8 flavours, and SU(3) gauge theory with 12 flavours. For the SU(2) case, at strong bare coupling, $\beta \lesssim 1.45$, the distribution of the lowest eigenvalue of the Dirac operator…
It has been argued recently that the inclusion of the chiral logarithms in extrapolation of the lattice data can shift the value of the hadronic parameter xi = (fBs sqrt(B_{Bs}))/(fBd sqrt(B_{Bd})), from 1.16(6) to 1.32(10) and even higher.…
We analyze the chiral behavior of the hadron spectrum obtained with quenched Wilson fermions on 170 $32^3 \times 64$ lattices at $\beta = 6.0$. We calculate masses of hadrons composed of both degenerate and non-degenerate quarks. We reduce…
We report on a first next-to-next-to-leading order calculation of the decay constants of the $D$ ($D^*$) and $B$ ($B^*$) mesons using a covariant formulation of chiral perturbation theory. It is shown that, using the state-of-the-art…
We investigate the quark mass dependence of baryon masses in 2+1 flavor lattice QCD using SU(3) heavy baryon chiral perturbation theory up to one-loop order. The baryon mass data used for the analyses are obtained for the degenerate up-down…
We report on the status of our kaon semileptonic form factor calculations using the highly-improved staggered quark (HISQ) formulation to simulate the valence fermions. We present results for the form factor f_+^{K \pi}(0) on the asqtad…
It has been conjectured that spontaneous chiral symmetry breaking in strongly coupled vectorlike gauge theories falls into only three different classes, depending on the gauge group and the representations carried by the fermions. We test…
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 $a\approx…
We present determinations of the B meson decay constant f_B and of the ratio f_{B_s}/f_B using the MILC collaboration unquenched gauge configurations which include three flavors of light sea quarks. The mass of one of the sea quarks is kept…
We present an improved QCD light-cone sum rule (LCSR) calculation of the B -> K and Bs -> K form factors, by including SU(3)-symmetry breaking corrections. We use recently updated K-meson distribution amplitudes which incorporate the…
We calculate the baryon magnetic moments using covariant Chiral Perturbation Theory ($\chi$PT) within the Extended-on-mass-shell (EOMS) renormalization scheme. By fitting the two available low-energy constants (LECs), we improve the…
The chiral properties of lattice fermions can be improved by altering either their fermion-gauge coupling or the pure gauge part of the action (or both). Using both perturbation theory and nonperturbative simulation, we compare a simple…
We deliver the realistic ab initio lattice investigations of $K \overline{K}$ scattering. In the Asqtad-improved staggered dynamical fermion formulation, we carefully measure $K\overline{K}$ four-point function in the $I=0$ channel by…
We update the Standard Model predictions for the rare decays $K^+\to\pi^+\nu\bar\nu$ and $K_L\to\pi^0\nu\bar\nu$. In view of improved limits on $B_s$--$\bar B_s$ mixing we derive a stringent and theoretically clean Standard Model upper…
We present a model based on $S_1$ scalar leptoquarks to solve the tension observed in the recently proposed non-leptonic optimized observables $L_{K^{*} \bar{K}^{*}}$ and $L_{K \bar{K}}$. These observables are constructed as ratios of…
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 present the results of fits to recent asqtad data in the light pseudoscalar sector using SU(2) partially-quenched staggered chiral perturbation theory. Superfine (a~0.06 fm) and ultrafine (a~0.045 fm) ensembles are used, where light sea…
We discuss the impact of recent LHCb data on the B -> K* mu+mu- decay for New Physics searches. We use an optimised set of observables with a limited sensitivity to hadronic inputs (form factors), leading to a significant deviation from the…
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…