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Related papers: Pion spectrum using improved staggered fermions

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We present results from simulations of two dynamical flavors of improved Wilson fermions with nHYP smeared gauge links. We demonstrate that the simulation is stable at a pseudo-scalar mass of 360MeV, a 2.1fm box and a lattice spacing of…

High Energy Physics - Lattice · Physics 2009-04-14 Anna Hasenfratz , Roland Hoffmann , Stefan Schaefer

We present new results in an ongoing study of the nature of the high temperature crossover in QCD with two light fermion flavors. These results are obtained with the conventional staggered fermion action at the smallest lattice spacing to…

High Energy Physics - Lattice · Physics 2009-10-28 C. Bernard , T. Blum , C. DeTar , Steven Gottlieb , Urs M. Heller , J. Hetrick , K. Rummukainen , S. Sugar , D. Toussaint , M. Wingate

We study the set of models in which the Standard Model symmetry is extended with the flavour group A4 and there are three copies of the Standard Model Higgs that transform as a triplet under this group. In this setup, new channels for…

High Energy Physics - Phenomenology · Physics 2012-12-07 Reinier de Adelhart Toorop , Federica Bazzocchi , Luca Merlo , Alessio Paris

We present updated results for kaon B-parameters for operators arising in models of new physics. We use HYP-smeared staggered quarks on the $N_f = 2+1$ MILC asqtad lattices. During the last year we have added new ensembles, which has…

We present preliminary results of light hadron spectroscopy using valence, tadpole-improved, Clover fermions on an ensemble of gauge configurations generated with 2 flavors of staggered fermions at a beta of 5.6. We compare the slope and…

High Energy Physics - Lattice · Physics 2010-01-18 Sara Collins , Robert G. Edwards , Urs M. Heller , John Sloan

We report the findings of our extensive study of the spectra of flavoured mesons in lattice gauge theories with symplectic gauge group and fermion matter content treated in the quenched approximation. For the $Sp(4)$, $Sp(6)$, and $Sp(8)$…

High Energy Physics - Lattice · Physics 2024-04-17 Ed Bennett , Jack Holligan , Deog Ki Hong , Jong-Wan Lee , C. -J. David Lin , Biagio Lucini , Maurizio Piai , Davide Vadacchino

We present results of an ongoing study of the nature of the high temperature crossover in QCD with two light fermion flavors. These results are obtained with the conventional staggered fermion action at the smallest lattice spacing to…

We show that the size of the O(a^2) flavour violating cutoff artifacts that have been found to affect the value of the neutral pion mass in simulations with maximally twisted Wilson fermions is controlled by a continuum QCD quantity that is…

High Energy Physics - Lattice · Physics 2008-11-26 Roberto Frezzotti , Giancarlo Rossi

The R algorithm is widely used for simulating two flavours of dynamical staggered fermions. We give a simple proof that the algorithm converges to the desired probability distribution to within O(dt^2) errors, but show that the relevant…

High Energy Physics - Lattice · Physics 2009-11-07 M. A. Clark , B. Joo , A. D. Kennedy

We calculate the B-parameters for operators arising in theories of new physics beyond the standard model (BSM) using HYP-smeared improved staggered fermions on the MILC asqtad lattices with N_f = 2+1 flavors. We use three different lattice…

Using the lattice simulations in the Asqtad-improved staggered fermion formulation we compute the point-to-point $\kappa$ correlators, which are analyzed by the rooted staggered chiral perturbation theory (rS$\chi$PT). After chiral…

High Energy Physics - Lattice · Physics 2013-06-03 Ziwen Fu

We conclude our investigations on the QCD cross-over transition temperatures with 2+1 staggered flavours and one-link stout improvement. We extend our previous two studies [Phys. Lett. B643 (2006) 46, JHEP 0906:088 (2009)] by choosing even…

High Energy Physics - Lattice · Physics 2010-11-19 Szabolcs Borsanyi , Zoltan Fodor , Christian Hoelbling , Sandor D. Katz , Stefan Krieg , Claudia Ratti , Kalman K. Szabo

We calculate the kaon B-parameter, B_K, in chiral perturbation theory for a partially quenched, mixed action theory with Ginsparg-Wilson valence quarks and staggered sea quarks. We find that the resulting expression is similar to that in…

High Energy Physics - Lattice · Physics 2014-11-17 C. Aubin , Jack Laiho , Ruth S. Van de Water

Adopting a mixed action approach, we report here results on hadron spectra containing one or more charm quarks. We use overlap valence quarks on a background of 2+1+1 flavor HISQ gauge configurations generated by the MILC collaboration. We…

High Energy Physics - Lattice · Physics 2013-12-12 S. Basak , S. Datta , A. T. Lytle , M. Padmanath , P. Majumdar , N. Mathur

We analyze the cut-off dependence of the fermion contribution to the finite temperature free energy density in ${\cal O}(g^2)$ lattice perturbation theory for several improved staggered fermion actions. Cut-off effects are drastically…

High Energy Physics - Lattice · Physics 2010-11-19 U. M. Heller , F. Karsch , B. Sturm

We present an exploratory calculation of the $I=2$ $\pi-\pi$ scattering amplitude at threshold using Wilson fermions in the quenched approximation, including all the required contractions. We find good agreement with the predictions of…

High Energy Physics - Lattice · Physics 2009-10-22 Rajan Gupta , Apoorva Patel , Stephen Sharpe

We introduce a new smearing transformation, the hypercubic (HYP) fat link. The hypercubic fat link mixes gauge links within hypercubes attached to the original link only. Using quenched lattices at beta = 5.7 and 6.0 we show that HYP fat…

High Energy Physics - Lattice · Physics 2009-11-07 A. Hasenfratz , F. Knechtli

Based on the symmetry properties of graphene lattice, we derive the effective Hamiltonian of graphene under spatially non-uniform acoustic and optical strains. We show that with the proper selection of the parameters, the obtained…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 T. L. Linnik

A different lattice fermion method is introduced. Staggered domain wall fermions are defined in 2n+1 dimensions and describe 2^n flavors of light lattice fermions with exact U(1) x U(1) chiral symmetry in 2n dimensions. As the size of the…

High Energy Physics - Lattice · Physics 2009-11-07 George T. Fleming , Pavlos M. Vranas

The chiral properties of lattice fermions can be improved by altering either their fermion-gauge coupling or the pure gauge part of the action (or both). Using both perturbation theory and nonperturbative simulation, we compare a simple…

High Energy Physics - Lattice · Physics 2016-09-01 Thomas DeGrand , Anna Hasenfratz , Tamas G. Kovacs