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Non-Standard Physics in Leptonic and Semileptonic Decays of Charmed Mesons

Description: Recent measurements of the branching fraction for D{sub s} {yields} {ell}v disagree with the Standard Model expectation, which relies on calculations of f{sub D{sub s}} from lattice QCD. This paper uses recent preliminary measurements from CLEO and a new preliminary lattice-QCD result from this conference to update the significance of the discrepancy. The 'f{sub D{sub s}} puzzle' stands now at 3.5{sigma}, with {sigma} predominantly from the statistical uncertainty of the experiments. New physic… more
Date: December 1, 2008
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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Quantum chromodynamics with advanced computing

Description: We survey results in lattice quantum chromodynamics from groups in the USQCD Collaboration. The main focus is on physics, but many aspects of the discussion are aimed at an audience of computational physicists.
Date: July 1, 2008
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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The lightness of being: mass, ether, and unification of the forces

Description: How can an electron be both a wave and a particle? At the same time? Because it is a quantum field. That key insight seems to be underappreciated, given the awe and mysticism that permeate most nontechnical discussions of modern physics. Perhaps the root of the problem is that most popularizations of quantum mechanics and of particle physics shy away from quantized fields, the natural language for microscopic phenomena. In 'The Lightness of Being: Mass, Ether, and the Unification of Forces', Fr… more
Date: March 1, 2009
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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Predictions with Lattice QCD

Description: In recent years, they used lattice QCD to calculate some quantities that were unknown or poorly known. They are the q{sup 2} dependence of the form factor in semileptonic D {yields} Kl{nu} decay, the leptonic decay constants of the D{sup +} and D{sub s} mesons, and the mass of the B{sub c} meson. In this paper, they summarize these calculations, with emphasis on their (subsequent) confirmation by measurements in e{sup +}e{sup -}, {gamma}p and {bar p}p collisions.
Date: July 1, 2006
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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QCD: results from lattice quantum chromodynamics

Description: Quantum chromodynamics (QCD) is the modern theory of the strong force. In this theory, the main objects are quarks and gluons, which are bound by the strong force into protons, neutrons, and other particles called hadrons. In the framework of QCD, the strong nuclear force binding protons and neutrons together into nuclei is actually only a residue of the much stronger forces acting between quarks and gluons. In fact, inside the proton, even the concept of force is not very useful. Within all ha… more
Date: October 1, 2006
Creator: Kronfeld, Andreas S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Twenty-first Century Lattice Gauge Theory: Results from the QCD Lagrangian

Description: Quantum chromodynamics (QCD) reduces the strong interactions, in all their variety, to an elegant nonabelian gauge theory. It clearly and elegantly explains hadrons at short distances, which has led to its universal acceptance. Since its advent, however, many of its long-distance, emergent properties have been believed to be true, without having been demonstrated to be true. This paper reviews a variety of results in this regime that have been established with lattice gauge theory, directly fro… more
Date: March 1, 2012
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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New lattice action for heavy quarks

Description: We extend the Fermilab method for heavy quarks to include interactions of dimension six and seven in the action. There are, in general, many new interactions, but we carry out the calculations needed to match the lattice action to continuum QCD at the tree level, finding six non-zero couplings. Using the heavy-quark theory of cutoff effects, we estimate how large the remaining discretization errors are. We find that our tree-level matching, augmented with one-loop matching of the dimension-five… more
Date: March 1, 2008
Creator: Oktay, Mehmet B. & Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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An Improved action for heavy quarks

Description: We extend the Fermilab method for heavy quarks to include all interactions of dimension six in the action. We discuss a subtlety in the power counting, which implies that, for heavy quarks, certain interactions of dimension seven are commensurate with some of those of dimension six. We then present tree-level matching conditions obtained from calculating the Compton scattering amplitude for (lattice) QCD. When the matching conditions have been applied, the improved action removes (tree-level) d… more
Date: October 1, 2006
Creator: Kronfeld, Andreas S. & Oktay, Mehmet B.
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Partner: UNT Libraries Government Documents Department
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Progress in lattice QCD

Description: After reviewing some of the mathematical foundations and numerical difficulties facing lattice QCD, I review the status of several calculations relevant to experimental high-energy physics. The topics considered are moments of structure functions, which may prove relevant to search for new phenomena at the LHC, and several aspects of flavor physics, which are relevant to understanding CP and flavor violation.
Date: September 30, 2002
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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Lattice QCD calculations of leptonic and semileptonic decays

Description: In lattice QCD, obtaining properties of heavy-light mesons has been easier said than done. Focusing on the B meson's decay constant, it is argued that towards the end of 1997 the last obstacles were removed, at least in the quenched approximation. These developments, which resulted from a fuller understanding and implementation of ideas in effective field theory, bode well for current studies of neutral meson mixing and of semileptonic decays.
Date: December 1, 1998
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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Lattice QCD and the unitarity triangle

Description: Theoretical and computational advances in lattice calculations are reviewed, with focus on examples relevant to the unitarity triangle of the CKM matrix. Recent progress in semi-leptonic form factors for B {yields} {pi}/v and B {yields} D*lv, as well as the parameter {zeta} in B{sup 0}-{bar B}{sup 0} mixing, are highlighted.
Date: December 3, 2001
Creator: Kronfeld, Andreas S
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Partner: UNT Libraries Government Documents Department
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B and D mesons in lattice QCD

Description: Computational and theoretical developments in lattice QCD calculations of B and D mesons are surveyed. Several topical examples are given: new ideas for calculating the HQET parameters {bar {Lambda}} and {lambda}{sub 1}; form factors needed to determine {vert_bar}V{sub cb}{vert_bar} and {vert_bar}V{sub ub}{vert_bar}; bag parameters for the mass differences of the B mesons; and decay constants. Prospects for removing the quenched approximation are discussed.
Date: October 17, 2000
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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Renormalization of currents for massive fermions

Description: The renormalization of vector and axial-vector currents for massive fermions (in the ''Fermilab formalism'') is discussed. We give results for non-degenerate masses, which are needed for semi-leptonic form factors.
Date: December 1, 1998
Creator: Kronfeld, Andreas S. & Hashimoto, Shoji
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Partner: UNT Libraries Government Documents Department
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Heavy quarks and lattice QCD

Description: This paper is a review of heavy quarks in lattice gauge theory, focusing on methodology. It includes a status report on some of the calculations that are relevant to heavy-quark spectroscopy and to flavor physics.
Date: November 5, 2003
Creator: Kronfeld, Andreas S.
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Partner: UNT Libraries Government Documents Department
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Lambda-bar, lambda(1) and m(b) in three-flavor (lattice) QCD

Description: The heavy-quark expansion for inclusive semi-leptonic B decays introduces {Lambda} and {lambda}1 , which are matrix elements in heavy-quark effective field theory. We review how they can be obtained from an analysis of the heavy quark mass dependence of heavy-light meson masses in lattice QCD. We present preliminary results for the bottom quark mass, mb, using {Lambda} and {lambda}1 for the Bs meson from a 2+1 sea-flavor unquenched calculation.
Date: October 1, 2006
Creator: Freeland, Elizabeth D.; Kronfeld, Andreas S.; Simone, James N. & Van de Water, Ruth S.
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Partner: UNT Libraries Government Documents Department
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Heavy-Quark Masses from the Fermilab Method in Three-Flavor Lattice QCD

Description: We report on heavy quark mass calculations using Fermilab heavy quarks. Lattice calculations of heavy-strange meson masses are combined with one-loop (automated) lattice perturbation theory to arrive at the quark mass. Mesons are constructed from Fermilab heavy quarks and staggered light quarks. We use the MILC ensembles at three lattice spacings and sea quark mass ratios of m{sub u,d}/m{sub s} = 0.1 to 0.4. Preliminary results for the bottom quark are given in the potential subtracted scheme.
Date: October 1, 2007
Creator: Freeland, Elizabeth D.; /Fermilab, /Art Inst. of Chicago; Kronfeld, Andreas S.; Simone, James N. & Van de Water, Ruth S.
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Partner: UNT Libraries Government Documents Department
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Mass of the B(c) meson in three-flavor lattice QCD

Description: The authors use lattice QCD to predict the mass of the B{sub c} meson. They 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). The final result is m{sub B{sub c}} = 6304 {+-} 12{sub -0}{sup +18} MeV. The first error bar is a sum in quadrature of statistical and systematic uncertainties, and the second is an estimate of heavy-quark discretization effects.
Date: November 1, 2004
Creator: Allison, Ian F.; Davies, Christine T. H.; Gray, Alan; Kronfeld, Andreas S.; Mackenzie, Paul B. & Simone, James N.
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Partner: UNT Libraries Government Documents Department
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Semileptonic B to D Decays at Nonzero Recoil with 2+1 Flavors of Improved Staggered Quarks

Description: The Fermilab Lattice-MILC collaboration is completing a comprehensive program of heavy-light physics on the MILC (2+1)-flavor asqtad ensembles with lattice spacings as small as 0.045 fm and light-to-strange-quark mass ratios as low as 1/20. We use the Fermilab interpretation of the clover action for heavy valence quarks and the asqtad action for light valence quarks. The central goal of the program is to provide ever more exacting tests of the unitarity of the CKM matrix. We give a progress rep… more
Date: November 1, 2011
Creator: Qiu, Si-Wei; DeTar, Carleton; Du, Daping; Kronfeld, Andreas S.; Laiho, Jack & Van de Water, Ruth S.
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Partner: UNT Libraries Government Documents Department
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Form Factors for $B$ to $Kll$ Semileptonic Decay from Three-Flavor Lattice QCD

Description: We study the B {yields} Kl{sup +}l{sup -} semileptonic decay process in three-flavor lattice QCD. We analyze several ensembles generated by theMILC collaboration at different lattice spacings and sea-quark masses. We use the asqtad improved staggered action for the light quarks and the clover action with the Fermilab interpretation for the heavy b quark. We present preliminary results for the vector current induced form factors for a range of kaon energies. Our analysis includes chiral and cont… more
Date: November 1, 2011
Creator: Zhou, Ran; U., /Indiana; Bailey, Jon A.; U., /Seoul Natl.; Bazavov, Alexei; /Brookhaven et al.
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Partner: UNT Libraries Government Documents Department
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Charmed meson decay constants in three-flavor lattice QCD

Description: The authors present the first lattice QCD calculation with realistic sea quark content of the D{sup +}-meson decay constant f{sub D+}. They use the MILC Collaboration's publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). They obtain f{sub D+} = 201 {+-} 3 {+-} 17 MeV, where the errors are statistical and a combination of systematic errors. They also obtain f{sub D{sub s}} = 249 {+-} 3 {+-} 16 MeV for th… more
Date: June 1, 2005
Creator: Aubin, C.; Bernard, C.; DeTar, C.; Di Pierro, M.; Freeland, Elizabeth D.; Gottlieb, Steven et al.
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Partner: UNT Libraries Government Documents Department
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