相关论文: Improving Stochastic Estimator Techniques for Disc…
We perform a high statistics calculation of disconnected fermion loops on Graphics Processing Units for a range of nucleon matrix elements extracted using lattice QCD. The isoscalar electromagnetic and axial vector form factors, the…
We present evidence for disconnected contributions to the $\sigma_{\pi N}$ term and the flavor singlet axial coupling $g_A^0$ of the proton on full QCD configurations, which are obtained by means of improved stochastic estimator techniques.…
We present recent results of SESAM's large scale lattice simulation of QCD with two dynamical flavours of Wilson fermions. The emphasis is on future prospects in the extraction of flavour-singlet matrix elements, i.e the pi-nucleon sigma…
We calculate connected and disconnected contributions to the flavour singlet scalar density amplitude of the nucleon in a full QCD lattice simulation with $n_f=2$ dynamical Wilson fermions at $\beta=5.6$ on a $16^3 \times 32$ lattice. We…
We present results for the b \bar b spectrum obtained using an O(M_bv^6)-correct non-relativistic lattice QCD action. Propagators are evaluated on SESAM's three sets of dynamical gauge configurations generated with two flavours of Wilson…
Many observables of interest in lattice QCD are extracted from correlation functions involving the vector current. If Wilson fermions are used, it is therefore of practical importance that, besides the action, the current be O($a$) improved…
A discussion of methods for reducing the noise variance of flavor singlet quantities ("disconnected diagrams") in lattice QCD is given. After an introduction, the possible advantage of partitioning the Wilson fermion matrix into disjoint…
We report on the determination of the improvement coefficient $c_{\rm A}$ for the non-singlet axial-vector current $A^{a}_{\mu}(x)$ in the framework of stabilised Wilson-Clover fermions within three flavour lattice QCD. This is done by…
Results from two studies of full QCD with two flavours of dynamical Wilson fermions are presented. At beta=5.6, the region 0.83 > m_pi/m_rho > 0.56 at m_pia > 0.23 L^{-1} is explored. The SESAM collaboration has generated ensembles of about…
In these proceedings we address the computation of quark-line disconnected diagrams in lattice QCD. The evaluation of these diagrams is required for many phenomenologically interesting observables, but suffers from large statistical errors…
We give a full account of the Numerical Stochastic Perturbation Theory method for Lattice Gauge Theories. Particular relevance is given to the inclusion of dynamical fermions, which turns out to be surprisingly cheap in this context. We…
We develop an implementation for a recently proposed Noisy Monte Carlo approach to the simulation of lattice QCD with dynamical fermions by incorporating the full fermion determinant directly. Our algorithm uses a quenched gauge field…
The exact evaluation of the disconnected diagram contributions to the flavor-singlet pseudoscalar meson mass, the nucleon sigma term and the nucleon electromagnetic form factors, is carried out utilizing GPGPU technology with the NVIDIA…
First results of a recently started simulation of full QCD with two flavours of sea-quarks at a coupling of $\beta = 5.6$ on a $16^3 \times 32$ lattice are presented. Emphasis is laid on the statistical significance that can be achieved by…
We present results for the isoscalar electromagnetic form factors of the nucleon computed on the Coordinated Lattice Simulations (CLS) ensembles with $N_\mathrm{f} = 2 + 1$ flavors of $\mathcal{O}(a)$-improved Wilson fermions and an…
We present preliminary results for the static quark potential computed on some of the DWF lattice configurations generated by the RBC-UKQCD collaborations. Most of these results were obtained using Wilson lines joining spatial planes fixed…
Sea quark contributions to the scalar density and the axial current matrix elements of the nucleon are studied in lattice qcd with two flavours of dynamical wilson fermions. the results are compared to trends in heavy quark mass expansions,…
We demonstrate the utility of a spectral approximation to fermion loop operators using low-lying eigenmodes of the hermitian Dirac-Wilson matrix, Q. The investigation is based on a total of 400 full QCD vacuum configurations, with two…
We present results for the non-perturbative determination of the improvement and renormalization factors of the isovector axial current for lattice QCD with two flavors of dynamical Wilson quarks. The improvement and normalization…
We propose a new strategy to evaluate the partition function of lattice QCD with Wilson gauge action coupled to staggered fermions, based on a strong coupling expansion in the inverse bare gauge coupling $\beta= 2N/g^{2}$. Our method makes…