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A comparison is made of the (quenched) light hadron spectrum and of simple matrix elements for a hypercubic fermion action (based on a fixed point action) and the clover action, both using fat links, at a lattice spacing a= 0.18 fm.…

High Energy Physics - Lattice · Physics 2016-08-25 T. DeGrand

We present first results from a full QCD calculation on the CP-PACS, comparing various actions at $a^{-1} \sim 1 GeV$ and $m_\pi/m_\rho \approx 0.7$--0.9. We use the plaquette and a renormalization group improved action for the gluons, and…

High Energy Physics - Lattice · Physics 2012-08-27 PACS Collaboration , S. Aoki , G. Boyd , R. Burkhalter , S. Hashimoto , N. Ishizuka , Y. Iwasaki , K. Kanaya , T. Kaneko , Y. Kuramashi , M. Okawa , A. Ukawa , T. Yoshié

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

I describe studies of quenched spectroscopy, using crude approximations to fixed point actions for fermions interacting with SU(3) gauge fields. These actions have a hypercubic kinetic term and a complicated lattice anomalous magnetic…

High Energy Physics - Lattice · Physics 2009-10-30 T. DeGrand

We present a summary of our results for the light hadron spectrum in quenched lattice QCD and preliminary ones in two-flavor full QCD. For the quenched hadron spectrum we find that the mass formulae predicted by quenched chiral perturbation…

High Energy Physics - Lattice · Physics 2007-05-23 Yoshinobu Kuramashi

We present an update on the MILC Collaboration's light hadron spectrum calculation with two flavors of dynamical, staggered quarks. We present extrapolations of the nucleon to rho mass ratio to the continuum limit for fixed values of the pi…

I have performed scaling tests using quenched spectroscopy of a family of fermion actions which have a hypercubic kinetic term, gauge connections built of smeared links, and an anomalous magnetic moment term. These actions show improved…

High Energy Physics - Lattice · Physics 2010-11-19 MILC Collaboration , T. DeGrand

We describe a number of aspects in our attempt to construct an approximately perfect lattice action for QCD. Free quarks are made optimally local on the whole renormalized trajectory and their couplings are then truncated by imposing…

High Energy Physics - Lattice · Physics 2009-10-28 W. Bietenholz , R. Brower , S. Chandrasekharan , U. -J. Wiese

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

Lattice chiral fermions are synonymous to the Ginsparg-Wilson relation. Indeed, this relation is satisfied by the overlap, domain wall and perfect action fermion kernel. In a recent work we have shown that it is possible to take a direct RG…

High Energy Physics - Lattice · Physics 2008-11-26 Artan Borici

Recently, properties of the fixed point action for fermion theories have been pointed out indicating realization of chiral symmetry on the lattice. We check these properties by numerical analysis of the spectrum of a parametrized fixed…

High Energy Physics - Lattice · Physics 2009-10-31 F. Farchioni , I. Hip , C. B. Lang , M. Wohlgenannt

We present one-loop matching coefficients between continuum and lattice QCD for the heavy-light four-fermion operators relevant for neutral B meson mixing both within and beyond the Standard Model. For the lattice theory we use…

High Energy Physics - Lattice · Physics 2008-11-26 Elvira Gamiz , Junko Shigemitsu , Howard Trottier

We show that the perturbatively-improved gluon action for QCD, once it is tadpole-improved, gives accurate results even with lattice spacings as large as 0.4~fm. {\em No\/} tuning of the couplings is required. Using this action and lattice…

High Energy Physics - Lattice · Physics 2009-10-28 M. Alford , W. Dimm , G. Hockney , P. Lepage , P. Mackenzie

We present results of a perturbative matching calculation performed at one-loop for heavy-light currents. We use the Fermilab action for the heavy quarks, the Asqtad action for the light quarks, and an improved gluon action. We also present…

High Energy Physics - Lattice · Physics 2010-11-19 Aida X. El-Khadra , Elvira Gámiz , Andreas S. Kronfeld , Matthew A. Nobes

We report our progress constructing a fixed-point action for fermions interacting with SU(3) gauge fields.

High Energy Physics - Lattice · Physics 2009-10-28 T. DeGrand , A. Hasenfratz , P. Hasenfratz , P. Kunszt , F. Niedermayer

We present results for hadrons containing a strange quark in quenched lattice QCD. We calculate masses and decay constants using 60 gauge configurations with an O(a)-improved fermion action at beta = 6.2. Using the rho mass to set the…

High Energy Physics - Lattice · Physics 2007-05-23 D. G. Richards

CP-PACS and JLQCD Collaborations are carrying out a joint project of the 2+1 flavor full QCD with the RG-improved gauge action and the non-perturbatively ${\cal O}(a)$-improved Wilson quark action. This simulation removes quenching effects…

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 derive an effective action combining chiral and heavy quark symmetry, using approximate bosonization techniques of QCD. We explicitly show that the heavy-quark limit is compatible with the large $N_c$ (number of color) limit in the meson…

High Energy Physics - Phenomenology · Physics 2009-10-22 M. A. Nowak , M. Rho , I. Zahed

We present a high statistics study of the light hadron spectrum and quark masses in QCD with two flavors of dynamical quarks. Numerical simulations are carried out using the plaquette gauge action and the O(a)-improved Wilson quark action…