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By considering the local vector current between nucleon states and imposing charge conservation we determine, for $O(a)$ improved Wilson fermions, its renormalisation constant and quark mass improvement coefficient. The computation is…

High Energy Physics - Lattice · Physics 2008-11-26 T. Bakeyev , M. Gockeler , R. Horsley , D. Pleiter , P. E. L. Rakow , A. Schafer , G. Schierholz , H. Stuben

We discuss the improvement of flavour non-singlet point and one-link lattice quark operators, which describe the quark currents and the first moment of the DIS structure functions respectively. Suitable bases of improved operators are…

High Energy Physics - Lattice · Physics 2008-11-26 S. Capitani , M. Goeckeler , R. Horsley , H. Perlt , P. E. L. Rakow , G. Schierholz , A. Schiller

The ALPHA collaboration has determined the O(a) improved Wilson quark action for lattice spacings $a\leq 0.1$ fm, in the quenched approximation. We extend this result to coarser lattices, $a\leq 0.17$ fm, and calculate the hadron spectrum…

High Energy Physics - Lattice · Physics 2009-10-30 R. G. Edwards , U. M. Heller , T. R. Klassen

We present results at one-loop order of perturbation theory for various improvement coefficients in on-shell O($a$) improved lattice QCD. In particular we determine the additive counterterm required for on-shell improvement of the isovector…

High Energy Physics - Lattice · Physics 2009-10-30 Stefan Sint , Peter Weisz

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

We propose a method to improve lattice operators composed of Wilson fermions which allows the removal of all corrections of $O(a)$, including those proportional to the quark mass. It requires off-shell improvement of quark fields and…

High Energy Physics - Lattice · Physics 2009-10-09 G. Martinelli , G. C. Rossi , C. T. Sachrajda , S. Sharpe , M. Talevi , M. Testa

We present a lattice QCD determination of the b quark mass and of the B and B_s decay constants, performed with N_f=2 twisted mass Wilson fermions, by simulating at four values of the lattice spacing. In order to study the b quark on the…

We present the results of the physical point simulation in 2+1 flavor lattice QCD with the nonperturbatively $O(a)$-improved Wilson quark action and the Iwasaki gauge action at $\beta=1.9$ on a $32^3 \times 64$ lattice. The physical quark…

We present results of a lattice QCD application of a coordinate space renormalization scheme for the extraction of renormalization constants for flavour non-singlet bilinear quark operators. The method consists in the analysis of the…

High Energy Physics - Lattice · Physics 2012-12-03 Krzysztof Cichy , Karl Jansen , Piotr Korcyl

We report on the ALPHA Collaboration's lattice B-physics programme based on N_f=2 O(a) improved Wilson fermions and HQET, including all NLO effects in the inverse heavy quark mass, as well as non-perturbative renormalization and matching,…

We present lattice QCD results for the matrix elements of $R_2$ and other dimension-7, $\Delta B = 2$ operators relevant for calculations of $\Delta \Gamma_s$, the $B_s-\bar{B}_s$ width difference. We have computed correlation functions…

High Energy Physics - Lattice · Physics 2018-03-29 Christine Davies , Judd Harrison , G Peter Lepage , Christopher Monahan , Junko Shigemitsu , Matthew Wingate

The Alpha Collaboration has proposed an optimal value for c_SW in the Sheikholeslami-Wohlert action, chosen to remove O(a) effects. To measure hadronic matrix elements to the same accuracy we need a method of finding O(a) improved…

High Energy Physics - Lattice · Physics 2008-11-26 S. Capitani , M. Goeckeler , R. Horsley , H. Oelrich , H. Perlt , D. Pleiter , P. E. L. Rakow , G. Schierholz , A. Schiller , P. Stephenson

We present a determination of the strong coupling constant and heavy quark masses in (2+1)-flavor QCD using lattice calculations of the moments of the pseudo-scalar quarkonium correlators at several values of the heavy valence quark mass…

High Energy Physics - Lattice · Physics 2019-09-10 P. Petreczky , J. H. Weber

In view of the recent excitement about a tension between determinations of f_Ds from experiment and from simulations of lattice QCD with dynamical quarks, we try to clear up the picture of lattice determinations in the continuum limit of…

High Energy Physics - Lattice · Physics 2011-04-04 Jochen Heitger , Andreas Juttner

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 calculate the kaon $B$-parameter in quenched lattice QCD at $\beta=6.0$ using Wilson fermions at $\kappa=0.154$ and $0.155$. We use two kinds of non-local (``smeared'') sources for quark propagators to calculate the matrix elements…

High Energy Physics - Lattice · Physics 2009-10-22 Gupta , Daniel , Kilcup , Patel , Sharpe

We determine the masses and pseudoscalar decay constants of D and D_s mesons employing lattice QCD with non-perturbatively O(a) improved Wilson quarks and a tree-level Symanzik-improved gauge action. Our analysis is based on the…

High Energy Physics - Lattice · Physics 2017-01-20 Sara Collins , Kevin Eckert , Jochen Heitger , Stefan Hofmann , Wolfgang Soeldner

We present selected results obtained by RQCD from simulations of $N_f=2+1$ flavours of non-perturbatively $\mathcal{O}(a)$ improved Wilson fermions, employing open boundary conditions in time. The ensembles were created within the CLS…

Using conventional constituent-quark model, $I=1/2$ scalar $\kappa$, vector $K^\ast(892)$, and axial vector $K_1$ mesons are studied in the asqtad-improved staggered fermion with the wall-source and point-sink interpolators. The mass ratio…

High Energy Physics - Lattice · Physics 2015-06-10 Ziwen Fu

We study the vector and axial-vector current correlators in perturbative and non-perturbative regimes of QCD. The correlators in Euclidean coordinate space are calculated on the lattice using the M\"obius domain-wall fermion formulation at…

High Energy Physics - Lattice · Physics 2017-10-02 JLQCD collaboration , M. Tomii , G. Cossu , B. Fahy , H. Fukaya , S. Hashimoto , T. Kaneko , J. Noaki