Howard D. Trottier
Simon Fraser University
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Featured researches published by Howard D. Trottier.
Physical Review D | 2007
E. Follana; Q. Mason; C. T. H. Davies; K. Hornbostel; G. P. Lepage; Junko Shigemitsu; Howard D. Trottier; Kaven Henry Yau Wong
We use perturbative Symanzik improvement to create a new staggered-quark action (HISQ) that has greatly reduced one-loop taste-exchange errors, no tree-level order a{sup 2} errors, and no tree-level order (am){sup 4} errors to leading order in the quarks velocity v/c. We demonstrate with simulations that the resulting action has taste-exchange interactions that are 3-4 times smaller than the widely used ASQTAD action. We show how to bound errors due to taste exchange by comparing ASQTAD and HISQ simulations, and demonstrate with simulations that such errors are likely no more than 1% when HISQ is used for light quarks at lattice spacings of 1/10 fm or less. The suppression of (am){sup 4} errors also makes HISQ the most accurate discretization currently available for simulating c quarks. We demonstrate this in a new analysis of the {psi}-{eta}{sub c} mass splitting using the HISQ action on lattices where am{sub c}=0.43 and 0.66, with full-QCD gluon configurations (from MILC). We obtain a result of 111(5) MeV which compares well with the experiment. We discuss applications of this formalism to D physics and present our first high-precision results for D{sub s} mesons.
Physical Review Letters | 2005
C. Aubin; C. Bernard; Carleton DeTar; Massimo Dipierro; A. X. El-Khadra; Steven Gottlieb; Eric Brittain Gregory; U. M. Heller; James Edward Hetrick; Andreas S. Kronfeld; Paul B. Mackenzie; D. Menscher; M. Nobes; M. Okamoto; M.B. Oktay; J. Osborn; James N. Simone; R. L. Sugar; D. Toussaint; Howard D. Trottier
We present the first three-flavor lattice QCD calculations for D-->pilnu and D-->Klnu 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 Wilson-type light quarks. Our results for the form factors at q(2)=0 are f(D-->pi)(+)(0)=0.64(3)(6) and f(D-->K)(+)(0)=0.73(3)(7), where the first error is statistical and the second is systematic, added in quadrature. Combining our results with experimental branching ratios, we obtain the Cabibbo-Kobayashi-Maskawa matrix elements |V(cd)|=0.239(10)(24)(20) and |V(cs)|=0.969(39)(94)(24), where the last errors are from experimental uncertainties.
arXiv: High Energy Physics - Lattice | 2005
M. Okamoto; C. Aubin; C. Bernard; Carleton DeTar; M. Di Pierro; A. X. El-Khadra; Steven Gottlieb; Eric Brittain Gregory; U. M. Heller; James Edward Hetrick; Andreas S. Kronfeld; Paul B. Mackenzie; D. Menscher; M. Nobes; M.B. Oktay; J. Osborn; James N. Simone; R. Sugar; D. Toussaint; Howard D. Trottier
We present results for form factors of semileptonic decays of D and B mesons in 2 + 1 flavor lattice QCD using the MILC gauge configurations. With an improved staggered action for light quarks, we successfully reduce the systematic error from the chiral extrapolation. The results for D decays are in agreement with experimental ones. The results for B decays are preliminary. Combining our results with experimental branching ratios, we then obtain the CKM matrix elements | V c d | , | V c s | , | V c b | and | v u b | . We also check CKM unitarity, for the first time, using only lattice QCD as the theoretical input.
arXiv: High Energy Physics - Lattice | 2002
G. P. Lepage; B. Clark; C. T. H. Davies; K. Hornbostel; Paul B. Mackenzie; Colin Morningstar; Howard D. Trottier
We survey techniques for constrained curve fitting, based upon Bayesian statistics, that offer significant advantages over conventional techniques used by lattice field theorists.
Physical Review Letters | 2005
C. Aubin; C. Bernard; Carleton DeTar; M. Di Pierro; E. D. Freeland; Steven Gottlieb; U. M. Heller; James Edward Hetrick; A. X. El-Khadra; Andreas S. Kronfeld; L. Levkova; Paul B. Mackenzie; D. Menscher; F. Maresca; M. Nobes; M. Okamoto; Dru B. Renner; James N. Simone; R. L. Sugar; D. Toussaint; Howard D. Trottier
We present the first lattice QCD calculation with realistic sea quark content of the D+-meson decay constant f(D+). We use the MILC Collaborations publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). We obtain f(D+)=201+/-3+/-17 MeV, where the errors are statistical and a combination of systematic errors. We also obtain f(Ds)=249+/-3+/-16 MeV for the Ds meson.
Physical Review D | 2008
I. Allison; M. Steinhauser; J.H. Kuhn; R. M. Woloshyn; K.G. Chetyrkin; K. Hornbostel; C. Sturm; C. T. H. Davies; Junko Shigemitsu; E. Dalgic; Howard D. Trottier; R. R. Horgan; Craig McNeile; G. P. Lepage; E. Follana
We use lattice QCD simulations, with MILC configurations and HISQ
Physical Review Letters | 2010
C. T. H. Davies; Craig McNeile; Kaven Henry Yau Wong; E. Follana; R. R. Horgan; K. Hornbostel; G. P. Lepage; Junko Shigemitsu; Howard D. Trottier
c
Physical Review D | 2004
C. Aubin; C. Bernard; C. T. H. Davies; Carleton DeTar; Steven Gottlieb; Alan Gray; Eric Brittain Gregory; Joachim Hein; U. M. Heller; James Edward Hetrick; G. P. Lepage; Q. Mason; J. Osborn; Junko Shigemitsu; R. L. Sugar; D. Toussaint; Howard D. Trottier; Matthew Wingate
-quark propagators, to make very precise determinations of moments of charm-quark pseudoscalar, vector and axial-vector correlators. These moments are combined with new four-loop results from continuum perturbation theory to obtain several new determinations of the
Physical Review D | 2003
Matthew Wingate; Junko Shigemitsu; C. T. H. Davies; G. Peter Lepage; Howard D. Trottier
\msb
Physical Review D | 2002
Howard D. Trottier; Norman H. Shakespeare; G. P. Lepage; Paul B. Mackenzie
mass of the charm quark. We find