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S. Basak; A. Bazavov; C. Bernard; C. DeTar; E. Freeland; W. Freeman; J. Foley; Steven Gottlieb; U. M. Heller; J. E. Hetrick; J. Laiho; L. Levkova; M. Oktay; J. Osborn; R. L. Sugar; A. Torok; D. Toussaint; R. S. Van de Water; R. Zhou
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We report on the calculation by the MILC Collaboration of the electromagnetic effects on kaon and pion masses. These masses are computed in QCD with dynamical (asqtad staggered) quarks plus quenched photons at three lattice spacings varying from 0.12 to 0.06 fm. The masses are fit to staggered chiral perturbation theory with NLO electromagnetic terms, as well as analytic terms at higher order. We extrapolate the results to physical lightquark masses and to the continuum limit. At the current...
Source: http://arxiv.org/abs/1301.7137v1
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Jon A. Bailey; A. Bazavov; C. Bernard; C. Bouchard; C. DeTar; A. X. ElKhadra; E. D. Freeland; W. Freeman; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. B. Oktay; M. Di Pierro; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water
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Lattice calculations of the form factors for the charm semileptonic decays D to K l nu and D to pi l nu provide inputs to direct determinations of the CKM matrix elements V(cs) and V(cd) and can be designed to validate calculations of the form factors for the bottom semileptonic decays B to pi l nu and B to K l lbar. We are using Fermilab charm (bottom) quarks and asqtad staggered light quarks on the 2+1 flavor asqtad MILC ensembles to calculate the charm (bottom) form factors. We outline...
Source: http://arxiv.org/abs/0912.0214v1
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Ernest C. Bernard
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MILC Collaboration; C. Bernard; T. DeGrand; C. DeTar; Steven Gottlieb; Urs M. Heller; J. Hetrick; N. Ishizuka; C. McNeile; R. Sugar; D. Toussaint; M. Wingate
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We report on the results of a MILC collaboration calculation of $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios. We discuss the most important errors in more detail than we have elsewhere.
Source: http://arxiv.org/abs/heplat/9809109v2
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Jigang Jiang; Wenying Yin; Jianxiu Chen; Ernest C. Bernard
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"Athens in the Age of Pericles" is an article from The Classical Journal, Volume 15 . View more articles from The Classical Journal . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor3287768
Source: http://www.jstor.org/stable/10.2307/3287768
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Ruffin, C. Bernard (Caulbert Bernard), 1947
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257 pages ; 22 cm
Topics: United States, Women  Biography, Crosby, Fanny, 18201915, Poets, American  19th century ...
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C. Aubin; C. Bernard
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We merge heavy quark effective theory with staggered chiral perturbation theory to calculate heavylight (B, D) meson quantities. We present results at NLO for the $B(D)$ meson decay constant in the partially quenched and full QCD cases, and discuss the calculation of the form factors for $B(D) \to \pi(K) \ell \nu$ decays.
Source: http://arxiv.org/abs/heplat/0409027v1
US National Library of Medicine
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Unna, Paul Gerson, 18501929; Wolff, C. Bernard, translator; Heidelberg Society for Medical and Natural Science. Medical Section
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Caption title
Topics: Dermatitis, Chemotaxis
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C. Bernard; M. Golterman
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We summarize results for partially quenched chiral perturbation theory and indicate an application to staggered fermion QCD in which the square root of the determinant is taken to reduce the number of flavors from four to two.
Source: http://arxiv.org/abs/heplat/9311070v1
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C. Bernard; T. Blum; T. DeGrand; C. E. DeTar; Steven Gottlieb; U. M. Heller; J. E. Hetrick; C. McNeile; K. Rummukainen; R. L. Sugar; D. Toussaint; M. Wingate
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As part of a larger project to estimate the fB decay constant, we are recalculating fB_static using a variational smearing method in an effort to improve accuracy. Preliminary results for the static B_B parameter and HQET two point functions are also presented.
Source: http://arxiv.org/abs/heplat/9608088v1
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C. Bernard; B. Billeter; C. DeTar; L. Levkova; Steven Gottlieb; U. M. Heller; J. E. Hetrick; J. Osborn; D. B. Renner; D. Toussaint; R. Sugar
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We report new data for the topological susceptibility computed on 2+1 flavor dynamical configurations with lattice spacing 0.06 fm, generated with the asqtad action. The topological susceptibility is computed by HYP smearing and compared with rooted staggered chiral perturbation theory as the pion mass goes to zero. At 0.06 fm, the raw data is already quite close to the continuum extrapolated values obtained from coarser lattices. These results provide a further test of the asqtad action with...
Source: http://arxiv.org/abs/0710.3124v1
Bibliography: p.227228
Topics: Universities and colleges, Students
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Taylor, B. C. (Bernard Cullon), 1914; Prentice, Kenneth Edward, 1913 joint author; Lambert, G. R., joint author
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A. Bazavov; C. Bernard; C. DeTar; E. D. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; A. X. ElKhadra; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. B. Oktay; M. Di Pierro; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water
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We present the leptonic decay constants fDs and fD+ computed on the MILC collaboration's 2+1 flavor asqtad gauge ensembles. We use clover heavy quarks with the Fermilab interpretation and improved staggered light quarks. The simultaneous chiral and continuum extrapolation, which determines both decay constants, includes partiallyquenched lattice results at lattice spacings a ~ 0:09, 0:12 and 0:15 fm. We have made several recent improvements in our analysis: a) we include terms in the fit...
Source: http://arxiv.org/abs/0912.5221v1
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MILC Collaboration; C. Bernard; T. DeGrand; C. DeTar; Steven Gottlieb; Urs M. Heller; J. E. Hetrick; N. Ishizuka; C. McNeile; R. Sugar; D. Toussaint; M. Wingate
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We report on the MILC collaboration's calculation of $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$, and their ratios. Our central values come from the quenched approximation, but the quenching error is estimated from $N_F=2$ dynamical staggered lattices. We use Wilson light valence quarks and Wilson and static heavy quarks. We find, for example, $f_B=157 \pm 11 {}^{+25}_{9} {}^{+23}_{0} \MeV$, $f_{B_s}/f_B = 1.11 \pm 0.02 {}^{+0.04}_{0.03} \pm 0.03$, $f_{D_s} = 210 \pm 9 {}^{+25}_{9} {}^{+17}_{1}...
Source: http://arxiv.org/abs/hepph/9806412v2
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C. Bernard; T. DeGrand; C. DeTar; S. Gottlieb; U. M. Heller; J. Hetrick; P. Lacock; K. Orginos; R. L. Sugar; D. Toussaint
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The separation of a heavy quark and antiquark pair leads to the formation of a tube of flux, or "string", which should break in the presence of light quarkantiquark pairs. This expected zerotemperature phenomenon has proven elusive in simulations of lattice QCD. We study mixing between the string state and the twomeson decay channel in QCD with two flavors of dynamical sea quarks. We confirm that mixing is weak and find that it decreases at level crossing. While our study does not...
Source: http://arxiv.org/abs/heplat/0103012v2
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MILC Collaboration; C. Bernard; T. Burch; C. E. DeTar; Ziwen Fu; Steven Gottlieb; E. Gregory; U. M. Heller; J. Osborn; R. L. Sugar; D. Toussaint
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We are studying the effects of light dynamical quarks on the excitation energies of a flux tube between a static quark and antiquark. We report preliminary results of an analysis of the ground state potential and the $\Sigma^{\prime+}_g$ and $\Pi_u$ potentials. We have measured these potentials on closely matched ensembles of gauge configurations, generated in the quenched approximation and with 2+1 flavors of Asqtad improved staggered quarks.
Source: http://arxiv.org/abs/heplat/0209051v1
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C. Aubin; C. Bernard
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We incorporate heavylight mesons into staggered chiral perturbation theory, working to leading order in 1/m_Q, where m_Q is the heavy quark mass. At first nontrivial order in the chiral expansion, staggered taste violations affect the chiral logarithms for heavylight quantities only through the light meson propagators in loops. There are also new analytic contributions coming from additional terms in the Lagrangian involving heavylight and light mesons. Using this heavylight staggered...
Source: http://arxiv.org/abs/heplat/0510088v3
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A. Bazavov; C. Bernard; C. M. Bouchard; C. C. Chang; C. DeTar; Daping Du; A. X. ElKhadra; E. D. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; A. S. Kronfeld; J. Laiho; P. B. Mackenzie; E. T. Neil; J. Simone; R. Sugar; D. Toussaint; R. S. Van de Water; Ran Zhou
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We calculatefor the first time in threeflavor lattice QCDthe hadronic matrix elements of all five local operators that contribute to neutral $B^0$ and $B_s$meson mixing in and beyond the Standard Model. We present a complete error budget for each matrix element and also provide the full set of correlations among the matrix elements. We also present the corresponding bag parameters and their correlations, as well as specific combinations of the mixing matrix elements that enter the...
Topics: High Energy Physics  Phenomenology, High Energy Physics  Lattice
Source: http://arxiv.org/abs/1602.03560
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C. Bernard; T. Blum; T. DeGrand; C. DeTar; Steven Gottlieb; U. M. Heller; J. Hetrick; C. McNeile; K. Rummukainen; R. Sugar; D. Toussaint; M. Wingate
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The MILC collaboration computation of heavylight decay constants is described. Results for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios are presented. These results are still preliminary, but the analysis is close to being completed. Sources of systematic error, both within the quenched approximation and from quenching itself, are estimated, although the latter estimate is rather crude. A sample of our results is: $f_B=153 \pm 10 {}^{+36}_{13} {}^{+13}_{0} MeV$, $f_{B_s}/f_B = 1.10...
Source: http://arxiv.org/abs/hepph/9709328v1
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MILC Collaboration; A. Bazavov; C. Bernard; C. DeTar; X. Du; W. Freeman; Steven Gottlieb; Urs M. Heller; J. E. Hetrick; J. Laiho; L. Levkova; M. B. Oktay; J. Osborn; R. Sugar; D. Toussaint; R. S. Van de Water
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We present the current status of the MILC collaboration's calculations of the properties of the light pseudoscalar meson sector. We use asqtad staggered ensembles with 2+1 dynamical flavors down to $a \approx 0.045$ fm and light quark mass down to 0.05 $m_s$. Here we describe fits to the data using chiral forms from SU(3) chiral perturbation theory, including all staggered taste violations at NLO and the continuum NNLO chiral logarithms. We emphasize issues of convergence of the chiral...
Source: http://arxiv.org/abs/1012.0868v1
xii, 480 pages :
Topic: Psychology, Applied
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C. Bernard; T. Blum; A. De; T. DeGrand; C. DeTar; Steven Gottlieb; U. M. Heller; N. Ishizuka; L. Kärkkäinen; J. Labrenz; A. Soni; R. Sugar; D. Toussaint
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Preliminary results from the MILC collaboration for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios are presented. We compute in the quenched approximation at $\beta=6.3$, 6.0 and 5.7 with Wilson light quarks and static and Wilson heavy quarks. We attempt to quantify systematic errors due to finite volume, finite lattice spacing, large $am$, and fitting and extrapolation uncertainties. The hopping parameter approach of Henty and Kenway is used to treat the heavy quarks; the sources are...
Source: http://arxiv.org/abs/heplat/9411080v1
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C. Bernard T. Blum; C. DeTar; Steven Gottlieb; Urs M. Heller; J. Hetrick; K. Rummukainen; R. Sugar; D. Toussaint; M. Wingate
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Previous work at $6/g^2=5.7$ with quenched staggered quarks is extended with new calculations at 5.85 and 6.15 on lattices up to $32^3\times 64$. These calculations allow a more detailed study of extrapolation in quark mass, finite volume and lattice spacing than has heretofore been possible. We discuss how closely the quenched spectrum approaches that of the real world.
Source: http://arxiv.org/abs/heplat/9509076v1
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C. Bernard; T. Blum; T. A. DeGrand; C. DeTar; Steve Gottlieb; Urs M. Heller; J. Hetrick; C. McNeile; K. Rummukainen; R. L. Sugar; Doug Toussaint; M. Wingate
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We report on results from three spectrum calculations with staggered quarks: 1) a quenched calculation with the standard action for the gluons and quarks; 2) a quenched calculation with improved actions for both the gluons and quarks; and 3) a calculation with two flavors of dynamical quarks using the standard actions for the gluons and quarks.
Source: http://arxiv.org/abs/heplat/9608102v1
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C. Bernard; T. DeGrand; C. DeTar; Steven Gottlieb; E. Gregory; A. Hart; A. Hasenfratz; Urs Heller; J. Hetrick; J. Osborn; R. Sugar; D. Toussaint
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Chiral perturbation theory predicts that in quantum chromodymamics light dynamical quarks suppress the topological (instanton) susceptibility. We investigate this suppression through direct numerical simulation using the Asqtad improved lattice fermion action. This action holds promise for carrying out nonperturbative simulations over a range of quark masses for which chiral perturbation theory is expected to converge. To test the effectiveness of the action in capturing instanton physics, we...
Source: http://arxiv.org/abs/heplat/0308019v2
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C. Aubin; C. Bernard; C. DeTar; M. Di Pierro; A. ElKhadra; Steven Gottlieb; E. B. Gregory; U. M. Heller; J. Hetrick; A. S. Kronfeld; P. B. Mackenzie; D. Menscher; M. Nobes; M. Okamoto; M. B. Oktay; J. Osborn; J. Simone; R. Sugar; D. Toussaint; H. D. Trottier
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We present the first threeflavor lattice QCD calculations for $D\to \pi l\nu$ and $D\to K l\nu$ semileptonic decays. Simulations are carried out using ensembles of unquenched gauge fields generated by the MILC collaboration. With an improved staggered action for light quarks, we are able to simulate at light quark masses down to 1/8 of the strange mass. Consequently, the systematic error from the chiral extrapolation is much smaller than in previous calculations with Wilsontype light quarks....
Source: http://arxiv.org/abs/hepph/0408306v1
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Jon A. Bailey; C. Bernard; C. DeTar; M. Di Pierro; A. X. ElKhadra; R. T. Evans; E. D. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. Okamoto; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water
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We calculate the form factor f_+(q^2) for Bmeson semileptonic decay in unquenched lattice QCD with 2+1 flavors of light sea quarks. We use Asqtadimproved staggered light quarks and a Fermilab bottom quark on gauge configurations generated by the MILC Collaboration. We simulate with several light quark masses and at two lattice spacings, and extrapolate to the physical quark mass and continuum limit using heavylight meson staggered chiral perturbation theory. We then fit the lattice result...
Source: http://arxiv.org/abs/0811.3640v3
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Andreas S. Kronfeld; I. F. Allison; C. Aubin; C. Bernard; C. T. H. Davies; C. DeTar; M. Di Pierro; E. D. Freeland; Steven Gottlieb; A. Gray; E. Gregory; U. M. Heller; J. E. Hetrick; A. X. ElKhadra; L. Levkova; P. B. Mackenzie; F. Maresca; D. Menscher; M. Nobes; M. Okamoto; M. B. Oktay; J. Osborn; D. Renner; J. N. Simone; R. Sugar; D. Toussaint; H. D. Trottier
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In the past year, we calculated with lattice QCD three quantities that were unknown or poorly known. They are the $q^2$ dependence of the form factor in semileptonic $D\to Kl\nu$ decay, the decay constant of the $D$ meson, and the mass of the $B_c$ meson. In this talk, we summarize these calculations, with emphasis on their (subsequent) confirmation by experiments.
Source: http://arxiv.org/abs/heplat/0509169v2
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C. Bernard; C. Parrinello; A. Soni
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We consider pure glue QCD at beta=5.7, beta=6.0 and beta=6.3. We evaluate the gluon propagator both in time at zero 3momentum and in momentum space. From the former quantity we obtain evidence for a dynamically generated effective mass, which at beta=6.0 and beta=6.3 increases with the time separation of the sources, in agreement with earlier results. The momentum space propagator G(k) provides further evidence for mass generation. In particular, at beta=6.0, for k less than 1 GeV, the...
Source: http://arxiv.org/abs/heplat/9307001v1
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I calculate, at one loop in staggered chiral perturbation theory, the matrix elements of the complete set of five local operators that may contribute to B mixing both in the Standard Model and in beyondtheStandardModel theories. Lattice computations of these matrix elements by the Fermilab Lattice/MILC collaborations (and earlier by the HPQCD collaboration) convert a light staggered quark into a naive quark, and construct the relevant 4quark operators as local products of two local...
Source: http://arxiv.org/abs/1303.0435v2
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Fermilab Lattice; MILC Collaborations; :; Jon A. Bailey; A. Bazavov; C. Bernard; C. M. Bouchard; C. DeTar; Daping Du; A. X. ElKhadra; J. Foley; E. D. Freeland; E. Gámiz; Steven Gottlieb; U. M. Heller; J. Komijani; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; E. T. Neil; SiWei Qiu; J. Simone; R. Sugar; D. Toussaint; R. S. Van de Water; Ran Zhou
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We present the first unquenched latticeQCD calculation of the hadronic form factors for the exclusive decay $\overline{B} \rightarrow D \ell \overline{\nu}$ at nonzero recoil. We carry out numerical simulations on fourteen ensembles of gaugefield configurations generated with 2+1 flavors of asqtadimproved staggered sea quarks. The ensembles encompass a wide range of lattice spacings (approximately 0.045 to 0.12 fm) and ratios of light (up and down) to strange seaquark masses ranging from...
Topic: High Energy Physics  Lattice
Source: http://arxiv.org/abs/1503.07237
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MILC Collaboration; A. Bazavov; C. Bernard; N. Brown; C. DeTar; J. Foley; Steven Gottlieb; U. M. Heller; J. Komijani; J. Laiho; L. Levkova; R. L. Sugar; D. Toussaint; R. S. Van de Water
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We report on a scale determination with gradientflow techniques on the $N_f=2+1+1$ highly improved staggered quark ensembles generated by the MILC Collaboration. The ensembles include four lattice spacings, ranging from approximately 0.15 to 0.06 fm, and both physical and unphysical values of the quark masses. The scales $\sqrt{t_0}/a$ and $w_0/a$ and their treelevel improvements, $\sqrt{t_{0,{\rm imp}}}$ and $w_{0,{\rm imp}}$, are computed on each ensemble using Symanzik flow and the...
Topic: High Energy Physics  Lattice
Source: http://arxiv.org/abs/1503.02769
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C. Aubin; C. Bernard; C. DeTar; Steven Gottlieb; Urs M. Heller; K. Orginos; R. Sugar; D. Toussaint
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We compute chiral logarithms in the presence of "taste" symmetry breaking of staggered fermions. The lagrangian of Lee and Sharpe is generalized and then used to calculate the logs in $\pi$ and $K$ masses. We correct an error in Ref. [1] [C. Bernard, heplat/0111051]; the issue turns out to have implications for the comparison with simulations, even at tree level. MILC data with three light dynamical flavors can be well fit by our formulas. However, two new chiral parameters, which...
Source: http://arxiv.org/abs/heplat/0209066v1
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C. Aubin; C. Bernard
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We show how to compute chiral logarithms that take into account both the $\cO(a^2)$ tastesymmetry breaking of staggered fermions and the fourthroot trick that produces one taste per flavor. The calculation starts from the LeeSharpe Lagrangian generalized to multiple flavors. An error in a previous treatment by one of us is explained and corrected. The one loop chiral logarithm corrections to the pion and kaon masses in the full (unquenched), partially quenched, and quenched cases are...
Source: http://arxiv.org/abs/heplat/0304014v3
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MILC Collaboration; C. Bernard; T. Burch; C. DeTar; Steven Gottlieb; E. B. Gregory; U. M. Heller; J. Osborn; R. Sugar; D. Toussaint
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We report on preliminary results from multiparticle fits to meson propagators with three flavors of light dynamical quarks. We are able to measure excited states in propagators with pion quantum numbers, which we interpret as the pion 2S state, and is evidence of locality of the action. In the a_0 (0^{++}) propagators we find evidence for excited states which are probably the expected decay channels, pi+eta and K+Kbar.
Source: http://arxiv.org/abs/heplat/0309117v1
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MILC Collaboration; S. Basak; A. Bazavov; C. Bernard; C. DeTar; E. Freeland; J. Foley; Steven Gottlieb; U. M. Heller; J. Komijani; J. Laiho; L. Levkova; R. Li; J. Osborn; R. L. Sugar; A. Torok; D. Toussaint; R. S. Van de Water; R. Zhou
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For some time, the MILC Collaboration has been studying electromagnetic effects on light mesons. These calculations use fully dynamical QCD, but only quenched photons, which suffices to NLO in XPT. That is, the sea quarks are electrically neutral, while the valence quarks carry charge. For the photons we use the noncompact formalism. We have new results with lattice spacing as small as 0.045 fm and a large range of volumes. We consider how well chiral perturbation theory describes these...
Topics: High Energy Physics  Lattice, High Energy Physics  Phenomenology
Source: http://arxiv.org/abs/1510.04997
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The MILC Collaboration; C. Bernard; T. Blum; T. A. DeGrand; C. DeTar; S. Gottlieb; U. M. Heller; J. Hetrick; C. McNeile; K. Rummukainen; R. Sugar; D. Toussaint
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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 to rho mass ratio including the physical one.
Source: http://arxiv.org/abs/heplat/9710063v1
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MILC Collaboration; C. Aubin; C. Bernard; C. DeTar; Steven Gottlieb; E. B. Gregory; Urs M. Heller; J. E. Hetrick; J. Osborn; R. Sugar; D. Toussaint
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We compute pseudoscalar meson masses and decay constants using staggered quarks on lattices with three flavors of sea quarks and lattice spacings $\approx 0.12$ fm and $\approx 0.09$ fm. We fit partially quenched results to ``staggered chiral perturbation theory'' formulae, thereby taking into account the effects of tastesymmetry violations. Chiral logarithms are observed. From the fits we calculate $f_\pi$ and $f_K$, extract GasserLeutwyler parameters of the chiral Lagrangian, and (modulo...
Source: http://arxiv.org/abs/heplat/0309088v1
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C. Bernard; T. Blum; C. E. DeTar; U. M. Heller; S. Gottlieb; J. E. Hetrick; Beat Jegerlehner; K. Rummukainen; R. L. Sugar; D. Toussaint; M. Wingate
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Quantum chromodynamics with two zero mass flavors is expected to exhibit a phase transition with O(4) critical behavior. Fixing the universality class is important for phenomenology and for facilitating the extrapolation of simulation data to physical quark mass values. At Lattice '96 the Tsukuba and Bielefeld groups reported results from new simulations with dynamical staggered quarks at $N_t = 4$, which suggested a departure from the expected critical behavior. We report observations of...
Source: http://arxiv.org/abs/heplat/9710038v1
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I review the current status of lattice calculations of the properties of bound states containing one or more heavy quarks. Many of my remarks focus on the heavylight leptonic decay constants, such as $f_B$, for which the systematic errors have by now been quite well studied. I also discuss $B$parameters, semileptonic form factors, and the heavylight and heavyheavy spectra. Some of my ``world averages'' are: $f_B=200(30) MeV$, $f_B\sqrt{\hat B_{B_d}}= 230(40) MeV$, $f_{B_s}/f_B=1.16(4)$ and...
Source: http://arxiv.org/abs/heplat/0011064v2
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HPQCD collaboration; MILC collaboration; UKQCD collaboration; C. Aubin; C. Bernard; C. Davies; C. DeTar; Steven Gottlieb; A. Gray; E. Gregory; J. Hein; U. Heller; J. Hetrick; G. Lepage; Q. Mason; J. Osborn; J. Shigemitsu; R. Sugar; D. Toussaint; H. Trottier; M. Wingate
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We compute the strange quark mass $m_s$ and the average of the $u$ and $d$ quark masses $\hat m$ using full lattice QCD with three dynamical quarks combined with experimental values for the pion and kaon masses. The simulations have degenerate $u$ and $d$ quarks with masses $m_u=m_d\equiv \hat m$ as low as $m_s/8$, and two different values of the lattice spacing. The bare lattice quark masses obtained are converted to the $\msbar$ scheme using perturbation theory at $O(alpha_s)$. Our results...
Source: http://arxiv.org/abs/heplat/0405022v3
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Durr and Hoelbling recently observed that the continuum and chiral limits do not commute in the two dimensional, one flavor, Schwinger model with staggered fermions. I point out that such lack of commutativity can also be seen in fourdimensional staggered chiral perturbation theory (SChPT) in quenched or partially quenched quantities constructed to be particularly sensitive to the chiral limit. Although the physics involved in the SChPT examples is quite different from that in the Schwinger...
Source: http://arxiv.org/abs/heplat/0412030v3
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Jon A. Bailey; C. Bernard
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Motivated by simulation results for octet and decuplet baryon masses using 2+1 flavors of light staggered quarks, we are incorporating staggered lattice artifacts into heavy baryon chiral perturbation theory, calculating the masses of various staggered baryons, and studying the connection between the staggered baryons of the chiral theory and the staggered baryons of simulations. We present order (m_q)^(3/2) loop contributions to the masses of several staggered nucleons and discuss...
Source: http://arxiv.org/abs/heplat/0510006v1
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C. Bernard; T. Burch; C. DeTar; Steven Gottlieb; L. Levkova; U. M. Heller; J. E. Hetrick; R. Sugar; D. Toussaint
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We report results for the interaction measure, pressure and energy density for nonzero temperature QCD with 2+1 flavors of improved staggered quarks. In our simulations we use a Symanzik improved gauge action and the Asqtad $O(a^2)$ improved staggered quark action for lattices with temporal extent $N_t=4$ and 6. The heavy quark mass $m_s$ is fixed at approximately the physical strange quark mass and the two degenerate light quarks have masses $m_{ud}\approx0.1 m_s$ or $0.2 m_s$. The calculation...
Source: http://arxiv.org/abs/heplat/0611031v3
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C. Bernard; C. Parrinello; A. Soni
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We give preliminary numerical results for the gluon propagator evaluated both in coordinate and momentum space on a 16^3X40 quenched lattice at beta=6.0. Our findings are compared with earlier results in the literature at zero momentum. In addition, by considering nonzero momenta we attempt to extract the form of the propagator and compare it to continuum predictions formulated by Gribov and others. latex, file espcrc2.sty needed (appended at the end: search for espcrc2.sty).
Source: http://arxiv.org/abs/heplat/9211020v1
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C. Bernard; T. DeGrand; C. DeTar; Steven Gottlieb; U. M. Heller; J. Hetrick; C. McNeile; K. Rummukainen; R. Sugar; D. Toussaint; M. Wingate
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MILC collaboration results for \fB, \fBs, \fD, \fDs and their ratios are presented. These results are still preliminary, but the analysis is close to being completed. Sources of systematic error, both within the quenched approximation and from quenching itself, are estimated. We find, for example, $f_B=153\pm 10 {}^{+36}_{13} {}^{+13}_{0} MeV$, and $f_{B_s}/f_B = 1.10 \pm 0.02 {}^{+0.05}_{0.03} {}^{+0.03}_{0.02}$, where the errors are statistical, systematic (within the quenched...
Source: http://arxiv.org/abs/heplat/9709142v1
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A. Bazavov; C. Bernard; C. M. Bouchard; C. DeTar; M. Di Pierro; A. X. ElKhadra; R. T. Evans; E. D. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; R. Jain; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; E. T. Neil; M. B. Oktay; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water
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We calculate the leptonic decay constants of B_{(s)} and D_{(s)} mesons in lattice QCD using staggered light quarks and Fermilab bottom and charm quarks. We compute the heavylight meson correlation functions on the MILC asqtadimproved staggered gauge configurations which include the effects of three light dynamical sea quarks. We simulate with several values of the light valence and seaquark masses (down to ~m_s/10) and at three lattice spacings (a ~ 0.15, 0.12, and 0.09 fm) and extrapolate...
Source: http://arxiv.org/abs/1112.3051v1
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C. BernardMichel; L. Gardes; S. Girard
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Sliced Inverse Regression (SIR) is an effective method for dimension reduction in highdimensional regression problems. The original method, however, requires the inversion of the predictors covariance matrix. In case of collinearity between these predictors or small sample sizes compared to the dimension, the inversion is not possible and a regularization technique has to be used. Our approach is based on a Fisher Lecture given by R.D. Cook where it is shown that SIR axes can be interpreted as...
Source: http://arxiv.org/abs/1103.6118v1