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Related papers: Iterative methods for overlap and twisted mass fer…

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Some results in QCD_2 at large N are presented using the reduced model on the lattice. Overlap fermions are used to compute meson propagators.

High Energy Physics - Lattice · Physics 2009-11-07 J. Kiskis , R. Narayanan. H. Neuberger

We present simulation results obtained with overlap hypercube fermions in QCD near the chiral limit. We relate our results to chiral perturbation theory in both, the epsilon-regime and in the p-regime. In particular we measured the pion…

High Energy Physics - Lattice · Physics 2009-11-11 W. Bietenholz , S. Shcheredin

We present the comparison of the analytical microscopic spectral density for lattice QCD with $N_{\rm f}=2$ twisted mass fermions with the one obtained on the lattice utilizing configurations produced by the ETM collaboration. We extract…

High Energy Physics - Lattice · Physics 2015-11-02 Krzysztof Cichy , Elena Garcia-Ramos , K. Splittorff , Savvas Zafeiropoulos

In three dimensions, the effective action for the gauge field induced by integrating out a massless Dirac fermion is known to give either a parity-invariant or a parity-violating result, depending on the regularization scheme. We construct…

High Energy Physics - Theory · Physics 2009-10-30 Rajamani Narayanan , Jun Nishimura

We report on the lowest moment of parton distribution functions and generalized form factors for the pion at several values of the momentum transfer. Calculations are performed for N_f=2 flavors of O(a) improved Wilson fermions with pion…

High Energy Physics - Lattice · Physics 2013-12-02 G. Bali , S. Collins , B. Glässle , M. Göckeler , N. Javadi-Motaghi , J. Najjar , W. Söldner , A. Sternbeck

We present an investigation of gauge-invariant smearing for Wilson fermions in quenched lattice QCD on a $24^3 \times 48$ lattice at $\beta = 6.2$. We demonstrate a smearing algorithm that allows a substantial improvement in the…

High Energy Physics - Lattice · Physics 2012-08-27 UKQCD Collaboration

We perform a nonperturbative lattice calculation of the complex phase and modulus of the pion form factor in the timelike momentum region using the finite-volume technique. We use two ensembles of 2+1-flavor overlap fermion at pion masses…

High Energy Physics - Lattice · Physics 2015-03-18 Xu Feng , Sinya Aoki , Shoji Hashimoto , Takashi Kaneko

We present results for the eta prime meson and the topological susceptibility in two flavour lattice QCD. The results are obtained using Wilson twisted mass fermions at maximal twist with pion masses ranging from 340 MeV down to the…

In order to develop fast inversion algorithms we have used overlap solvers in two dimensions. Lattice QED theory with U(1) group symmetry in two dimensional space-times dimensions has always been a testing ground for algorithms. By the…

High Energy Physics - Lattice · Physics 2014-06-25 Dafina Xhako , Artan Boriçi

In the previous paper we developed a strong-coupling expansion for the lattice QCD with the overlap fermions and showed that L\"usher's "extended" chiral symmetry is spontaneously broken in some parameter region of the overlap fermions. In…

High Energy Physics - Lattice · Physics 2009-10-31 Ikuo Ichinose , Keiichi Nagao

Partially quenched Quantum Chromodynamics with Wilson fermions on a lattice is considered in the framework of chiral perturbation theory. Two degenerate quark flavours are associated with a chirally twisted mass term. The pion masses and…

High Energy Physics - Lattice · Physics 2010-12-17 Gernot Münster , Christian Schmidt , Enno E. Scholz

This thesis is dedicated to explore the feasibility of numerical calculations in the $\epsilon$--regime of QCD for the extraction of physical information. We apply two formulations of the Ginsparg-Wilson fermions the Neuberger operator and…

High Energy Physics - Lattice · Physics 2007-05-23 S. Shcheredin

We present first results for a study with two mass-degenerate dynamical Chirally Improved (CI) fermions on lattices of spatial extent 2.4 fm. The CI Dirac operator obeys the Ginsparg-Wilson condition in good approximation. The pion mass we…

High Energy Physics - Lattice · Physics 2009-04-14 R. Frigori , Ch. Gattringer , C. B. Lang , M. Limmer , T. Maurer , D. Mohler , A. Schäfer

We use the infinite volume reconstruction method to calculate the charged/neutral pion mass difference. The hadronic tensor is calculated on lattice QCD and then combined with an analytic photon propagator, and the mass splitting is…

High Energy Physics - Lattice · Physics 2022-02-23 Xu Feng , Luchang Jin , Michael Joseph Riberdy

We present the results of the recent high precision lattice calculation of the average up/down, strange and charm quark masses performed by ETMC with Nf=2 twisted mass Wilson fermions. The analysis includes data at four values of the…

High Energy Physics - Lattice · Physics 2011-04-22 B. Blossier , P. Dimopoulos , R. Frezzotti , V. Lubicz , M. Petschlies , G. C. Rossi , F. Sanfilippo , S. Simula , C. Tarantino

Critical slowing down for the Krylov Dirac solver presents a major obstacle to further advances in lattice field theory as it approaches the continuum solution. We propose a new multi-grid approach for chiral fermions, applicable to both…

High Energy Physics - Lattice · Physics 2020-12-30 Richard C. Brower , M. A. Clark , Dean Howarth , Evan S. Weinberg

I discuss the properties of pions in ``partially quenched'' theories, i.e. those in which the valence and sea quark masses, $m_V$ and $m_S$, are different. I point out that for lattice fermions which retain some chiral symmetry on the…

High Energy Physics - Lattice · Physics 2014-11-17 Stephen R. Sharpe

Quantum Chromodynamics on a lattice with Wilson fermions and a chirally twisted mass term is considered in the framework of chiral perturbation theory. For two and three numbers of quark flavours, respectively, with non-degenerate quark…

High Energy Physics - Lattice · Physics 2010-12-23 Gernot Münster , Tobias Sudmann

We test the reweighting of the quark determinant of O(a) improved Wilson fermions in the domain-decomposed hybrid Monte-Carlo algorithm. Specifically, we implement a reweighting in a twisted-mass parameter proposed by Palombi and L\"uscher…

High Energy Physics - Lattice · Physics 2011-11-17 Chuan Miao , Harvey B. Meyer , Hartmut Wittig

In this work, we report about the determination of nonperturbative OPE parameters from fits of continuum perturbation theory to the Landau gauge quark propagator. The propagators are computed numerically using lattice QCD with Nf=2…

High Energy Physics - Lattice · Physics 2013-06-03 Florian Burger , Vittorio Lubicz , Michael Müller-Preussker , Silvano Simula , Carsten Urbach