QCD spectrum with three quark flavors

Abstract

We present results from a lattice hadron spectrum calculation using three flavors of dynamical quarks -two light and one strange, and quenched simulations for comparison. These simulations were done using a one-loop Symanzik improved gauge action and an improved Kogut-Susskind quark action. The lattice spacings, and hence also the physical volumes, were tuned to be the same in all the runs to better expose differences due to flavor number. Lattice spacings were tuned using the static quark potential, so as a byproduct we obtain updated results for the effect of sea quarks on the static quark potential. We find indications that the full QCD meson spectrum is in better agreement with experiment than the quenched spectrum. For the 0 ++ (a 0 ) meson we see a coupling to two pseudoscalar mesons, or a meson decay on the lattice. 11.15Ha,12.38.GcTypeset using REVT E X

QCD with one compact spatial dimension

“…3.1. We employ the Hybrid Monte Carlo algorithm from the publicly available MILC code 2 for improved staggered quarks [21][22][23] on a Symanzik gauge background.…”

Nucleon mass and pion-nucleon sigma term from a chiral analysis of lattice QCD data

“…In general, we will use lQCD data that are not extrapolated to the continuum limit a → 0. Originally, discretized QCD actions break chiral symmetry even in the chiral limit by terms proportional to a [85][86][87] but modern lattice Green squares are from [53,54], black right-triangles are quenched data from [83] and red diamonds are unquenched data from [83]. The blue circle is the physical point.…”

“…Furthermore, we adopt H A = 9 5 g A obtained in the large-N c limit. Finally, we use lQCD data for the ∆(1232) [53,54,83] mass to determine the remaining two LECs M ∆0 and c 1∆ . As the available lattice results are rather scattered, we do not perform a rigorous fit to them but, instead, adopt the conservative attitude of setting a band that englobes all the lQCD points with their errorbars (see Fig.…”

“…Several collaborations have pursued lQCD simulations of the masses and σ πN using N f = 2+1 configurations [53][54][55][56][57][58][59][60][61][62][63][64]. The extrapolation to the physical point allows to determine σ πN together with other sigma terms and strangeness content of baryons.…”

Status of Kaon physics on the lattice

“…They first fit the NLO expression including NNLO analytic terms to a reduced data set including only lighter data points and subsequently extend the fit to the heavier data points by including NNNLO analytic terms [19]. HPQCD+UKQCD are simulating the partially quenched theory using HISQ [30] valence quarks on the MILC staggered sea [31,19]. Arguing that for this setup the taste splitting is reduced sufficiently, they rely on NLO SU (3) × SU (3) continuum chiral perturbation theory with added NNLO analytical and cut-off terms.…”