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Related papers: A tmQCD mixed-action approach to flavour physics

200 papers

We are studying a variety of semileptonic decays of heavy-light mesons in an effort to improve the determination of the heavy-quark Standard-Model CKM matrix elements. Our fermion action is a novel, improved ``fat'' clover action that…

High Energy Physics - Lattice · Physics 2009-10-31 C. Bernard , T. DeGrand , C. DeTar , S. Gottlieb , U. M. Heller , J. Hetrick , C. McNeile , K. Orginos , R. L. Sugar , D. Toussaint

We study lattice QCD with staggered sea and Ginsparg-Wilson valence quarks. The Symanzik effective action for this mixed lattice theory, including the lattice spacing contributions of O(a^2), is derived. Using this effective theory we…

High Energy Physics - Lattice · Physics 2009-11-11 Oliver Baer , Claude Bernard , Gautam Rupak , Noam Shoresh

The concept of simulating a variant of QCD with sea quarks which interact with the gluon configuration only via global gluonic quantities like $\int F\tilde F dx$ and $\int FF dx$ is tested for the case of the massive 2-flavour Schwinger…

High Energy Physics - Lattice · Physics 2009-10-31 Stephan Dürr

We calculate charmed meson spectra and decay constants in lattice QCD employing one-loop $O(a)$ improved heavy quark action and axial-vector currents. In quenched simulations at $a \sim 0.1$ fm with the plaquette gauge action as well as a…

High Energy Physics - Lattice · Physics 2007-05-23 Y. Kayaba , S. Aoki , M. Fukugita , K-I. Ishikawa , Y. Iwasaki , K. Kanaya , T. Kaneko , Y. Kuramashi , M. Okawa , A. Ukawa , T. Yoshié

We describe a new set of gauge configurations generated within the CLS effort. These ensembles have N_f=2+1 flavors of non-perturbatively improved Wilson fermions in the sea with the Luescher-Weisz action used for the gluons. Open boundary…

We have studied the light hadron spectrum and decay constants for quenched QCD at beta=6.2 on a 24^3x48 lattice. We compare the results obtained using a nearest-neighbour O(a)-improved ("clover") fermion action with those obtained using the…

High Energy Physics - Lattice · Physics 2019-06-05 UKQCD Collaboration , presented by Alan D. Simpson

We report on studies of simple matrix elements from simulations with two flavors of sea quarks, both staggered and Wilson. We show the decay constants of vector and pseudoscalar mesons. The effects of sea quarks are small. These simulations…

High Energy Physics - Lattice · Physics 2015-06-25 The High Energy Monte Carlo Grand Challenge

The improved Wilson quark action - the clover action - is constructed to have smaller discretization errors than the normal Wilson quark action. We test this in a quenched spectroscopy computation on 6 lattice ensembles with spacings from…

High Energy Physics - Lattice · Physics 2007-05-23 Sara Collins , R. G. Edwards , U. M. Heller , John Sloan

We report on a study of QCD thermodynamics with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad O(a^2) improved staggered quark action. Simulations were carried out with lattice spacings 1/4T, 1/6T and 1/8T…

High Energy Physics - Lattice · Physics 2008-11-26 The MILC Collaboration , C. Bernard , T. Burch , C. DeTar , Steven Gottlieb , E. B. Gregory , U. M. Heller , J. Osborn , R. Sugar , D. Toussaint

We present the results of a partially quenched lattice QCD calculation of light quark masses with $N_f=2$ degenerate dynamical flavors. Numerical simulations are carried out using the plaquette gauge action and the Wilson quark action at…

High Energy Physics - Lattice · Physics 2010-03-19 D. Becirevic , B. Blossier , Ph. Boucaud , V. Gimenez , V. Lubicz , F. Mescia , S. Simula , C. Tarantino

In calculating hadronic contributions to precision observables for tests of the Standard Model in lattice QCD, the electromagnetic current plays a central role. Using a Wilson action with O($a$) improvement in QCD with $N_{\mathrm{f}}$…

High Energy Physics - Lattice · Physics 2019-02-20 Antoine Gerardin , Tim Harris , Harvey B. Meyer

The dependence of pseudo-scalar masses and decay constants on the sea and valence quark masses is investigated in the pseudo-Goldstone boson sector of QCD with two light quark flavours. The sea quark masses are at present in the range…

High Energy Physics - Lattice · Physics 2015-06-25 q Collaboration , F. Farchioni , C. Gebert , I. Montvay , E. Scholz , L. Scorzato

We study properties of pseudoscalar flavour-singlet mesons from Wilson twisted mass lattice QCD with Nf=2+1+1 dynamical quark flavors. Results for masses are presented at three values of the lattice spacing and light quark masses…

We present preliminary results of a determination of the semileptonic form factor for the decay of pseudoscalar heavy-light mesons to pseudoscalar light-light mesons in full QCD. In this preliminary study we focus on the effects of…

High Energy Physics - Lattice · Physics 2008-11-26 C. Bernard , C. DeTar , Steven Gottlieb , E. Gregory , Urs Heller , C. McNeile , J. Osborn , R. Sugar , D. Toussaint

We measure correlations appropriate for favour-singlet mesons using dynamical quark configurations from UKQCD. Improved methods of evaluating the disconnected quark diagrams are presented. The scalar and pseudoscalar meson channels are…

High Energy Physics - Lattice · Physics 2009-10-31 C. Michael , M. S. Foster , C. McNeile

Twisted mass lattice QCD (tmQCD), generalised to four Wilson quark flavours, can be used for the computation of some weak matrix elements related to $\Delta I=1/2$ transitions. Besides eliminating unphysical zero modes, tmQCD may alleviate…

High Energy Physics - Lattice · Physics 2008-11-26 C. Pena , S. Sint , A. Vladikas

We present the final results of the JLQCD calculation of the light hadron spectrum and quark masses with two flavors of dynamical quarks using the plaquette gauge action and fully $O(a)$-improved Wilson quark action at $\beta=5.2$. We…

It is shown how on-shell O(a) improvement can be implemented non-perturbatively in lattice QCD with Wilson quarks. Improvement conditions are obtained by requiring the PCAC relation to hold exactly in certain matrix elements. These are…

High Energy Physics - Lattice · Physics 2009-10-28 M. Lüscher , S. Sint , R. Sommer , P. Weisz , H. Wittig , U. Wolff

We report results for the interaction measure, pressure and energy density for nonzero temperature QCD with 2+1 flavors of improved staggered quarks. In our simulations we use a Symanzik improved gauge action and the Asqtad $O(a^2)$…

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

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…