1,542 results on '"Kronfeld, A. S."'
Search Results
152. A More Improved Lattice Action for Heavy Quarks
- Author
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Oktay, M. B., El-Khadra, A. X., Kronfeld, A. S., and Mackenzie, P. B.
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High Energy Physics - Lattice - Abstract
We extend the Fermilab formalism for heavy quarks to develop a more improved action. We give results of matching calculations of the improvement couplings at tree level. Finally, we estimate the discretization errors associated with the new action., Comment: 3 pages, 1 figure, Lattice 2003 Tsukuba Japan
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- 2003
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153. Semileptonic decays of $D$ mesons in unquenched lattice QCD
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Okamoto, Masataka, di Pierro, Massimo, El-Khadra, Aida X., Gottlieb, Steven, Kronfeld, Andreas S., Mackenzie, Paul B., Menscher, Damian P., Oktay, Mehmet B., and Simone, James N.
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High Energy Physics - Lattice - Abstract
We present our preliminary results for semileptonic form factors of $D$ mesons in unquenched lattice QCD. Simulations are carried out with $n_f=2+1$ dynamical quarks using gauge configurations generated by the MILC collaboration. For the valence quarks, we adopt an improved staggered light quark action and the clover heavy quark action. Our results for $D \to K$ and $D \to \pi$ form factors at $q^2=0$ are in agreement with the experimental values., Comment: Lattice2003(heavy), 3 pages
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- 2003
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154. High-Precision Lattice QCD Confronts Experiment
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Davies, C. T. H., Follana, E., Gray, A., Lepage, G. P., Mason, Q., Nobes, M., Shigemitsu, J., Trottier, H. D., Wingate, M., Aubin, C., Bernard, C., Burch, T., DeTar, C., Gottlieb, Steven, Gregory, E. B., Heller, U. M., Hetrick, J. E., Osborn, J., Sugar, R., Toussaint, D., Di Pierro, M., El-Khadra, A., Kronfeld, A. S., Mackenzie, P. B., Menscher, D., and Simone, J.
- Subjects
High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
We argue that high-precision lattice QCD is now possible, for the first time, because of a new improved staggered quark discretization. We compare a wide variety of nonperturbative calculations in QCD with experiment, and find agreement to within statistical and systematic errors of 3% or less. We also present a new determination of alpha_msbar(Mz); we obtain 0.121(3). We discuss the implications of this breakthrough for phenomenology and, in particular, for heavy-quark physics., Comment: 2 figures, revtex
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- 2003
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155. Charmonium with three flavors of dynamical quarks
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Di Pierro, Massimo, El-Khadra, Aida X., Gottlieb, Steven, Kronfeld, Andreas S., Mackenzie, Paul B., Menscher, Damian P., Oktay, Mehmet B., and Simone, James N.
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High Energy Physics - Lattice - Abstract
We present a calculation of the charmonium spectrum with three flavors of dynamical staggered quarks from gauge configurations that were generated by the MILC collaboration. We use the Fermilab action for the valence charm quarks. Our calculation of the spin-averaged 1P--1S and 2S--1S splittings yields a determination of the strong coupling, with $\ams(M_Z) = 0.119 (4)$., Comment: 6 pages, uses espcrc2.sty, Lattice2002(heavyquark)
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- 2002
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156. A Relativistic $O(a^2)$ Improved Action for Heavy Quarks
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Oktay, M. B., El-Khadra, A. X., Kronfeld, A. S., Mackenzie, P. B., and Simone, J. N.
- Subjects
High Energy Physics - Lattice - Abstract
We extend the Fermilab formalism for heavy quarks to develop an $O(a^2)$ improved relativistic action. We discuss our construction of the action, including the identification of redundant operators and the calculation of the improvement coefficients., Comment: Lattice 2002, 3pages
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- 2002
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157. Progress in Lattice QCD
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Kronfeld, Andreas S.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
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., Comment: Invited talk at the XXII Physics in Collisions Conference (PIC02), Stanford, Ca, USA, June 2002, 15+1 pp. PSN FRBT05
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- 2002
158. Remark on the Theoretical Uncertainty in $B^0$-$\bar{B}^0$ Mixing
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Ryan, Sinead M. and Kronfeld, Andreas S.
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High Energy Physics - Lattice - Abstract
We re-examine the theoretical uncertainty in the Standard Model expression for $B^0$-$\bar{B}^0$ mixing. We focus on lattice calculations of the ratio $\xi$, needed to relate the oscillation frequency of $B^0_s$-$\bar{B}^0_s$ mixing to $V_{td}$. We replace the usual linear chiral extrapolation with one that includes the logarithm that appears in chiral perturbation theory. We find a significant shift in the ratio $\xi$, from the conventional $1.15\pm0.05$ to $\xi=1.32\pm0.10$., Comment: Lattice2002(heavyquark), 3 pages, 3 figures
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- 2002
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159. Perturbative calculation of O(a) improvement coefficients
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Harada, Junpei, Hashimoto, Shoji, Kronfeld, Andreas S., and Onogi, Tetsuya
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High Energy Physics - Lattice - Abstract
We compute several coefficients needed for O(a) improvement of currents in perturbation theory, using the Brodsky-Lepage-Mackenzie prescription for choosing an optimal scale q*. We then compare the results to non-perturbative calculations. Normalization factors of the vector and axial vector currents show good agreement, especially when allowing for small two-loop effects. On the other hand, there are large discrepancies in the coefficients of O(a) improvement terms. We suspect that they arise primarily from power corrections inherent in the non-perturbative methods., Comment: 14pp, 3 figs (8 plots)
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- 2002
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160. F(1) for B -> D^*l\nu from Lattice QCD
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Kronfeld, Andreas S., Mackenzie, Paul B., Simone, James N., Hashimoto, Shoji, and Ryan, Sinead M.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
Short description of our calculation of the form factor needed to determine CKM element |V_{cb}| from the exclusive decay B -> D^*l\nu. For full details, see hep-ph/0110253. Also, here we recommend distribution for CKM fits., Comment: 5 pages. Presented by A. S. Kronfeld at Flavor Physics and CP Violation (FPCP), May 16--18, Philadelphia, Pennsylvania
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- 2002
161. Remark on the Theoretical Uncertainty in B^0-\bar{B}^0 Mixing
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Kronfeld, Andreas S. and Ryan, Sinead M.
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
We re-examine the theoretical uncertainty in the Standard Model expression for $B^0$-$\bar{B}^0$ mixing. We focus on lattice calculations of the ratio $\xi$, needed to relate the oscillation frequency of $B^0_s$-$\bar{B}^0_s$ mixing to the poorly known CKM element $V_{td}$. We replace the usual linear chiral extrapolation with one that includes the logarithm that appears in chiral perturbation theory. We find a significant shift in the ratio $\xi$, from the conventional $1.15\pm0.05$ to $\xi=1.32\pm0.10$., Comment: 10 pp., 4 figs; text on some other papers clarified, reference added
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- 2002
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162. Uses of Effective Field Theory in Lattice QCD
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Kronfeld, Andreas S.
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High Energy Physics - Lattice ,High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
Several physical problems in particle physics, nuclear physics, and astrophysics require information from non-perturbative QCD to gain a full understanding. In some cases the most reliable technique for quantitative results is to carry out large-scale numerical calculations in lattice gauge theory. As in any numerical technique, there are several sources of uncertainty. This chapter explains how effective field theories are used to keep them under control and, then, obtain a sensible error bar. After a short survey of the numerical technique, we explain why effective field theories are necessary and useful. Then four important cases are reviewed: Symanzik's effective field theory of lattice spacing effects; heavy-quark effective theory as a tool for controlling discretization effects of heavy quarks; chiral perturbation theory as a tool for reaching the chiral limit; and a general field theory of hadrons for deriving finite volume corrections., Comment: 67 pages. In v2, a few errors and many typos are corrected. Full Erratum at http://theory.fnal.gov/people/kronfeld/handbook/erratum.html for owners of the book
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- 2002
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163. B Physics at the Tevatron: Run II and Beyond
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Anikeev, K., Atwood, D., Azfar, F., Bailey, S., Bauer, C. W., Bell, W., Bodwin, G., Braaten, E., Burdman, G., Butler, J. N., Byrum, K., Cason, N., Cerri, A., Cheung, H. W. K., Dighe, A., Donati, S., Ellis, R. K., Falk, A., Feild, G., Fleming, S., Furic, I., Gardner, S., Grossman, Y., Gutierrez, G., Hao, W., Harris, B. W., Hewett, J., Hiller, G., Jesik, R., Jones, M., Kasper, P. A., El-Khadra, A., Kirk, M., Kiselev, V. V., Kroll, J., Kronfeld, A. S., Kutschke, R., Kuznetsov, V. E., Laenen, E., Lee, Jungil, Leibovich, A. K., Lewis, J. D., Ligeti, Z., Likhoded, A. K., Logan, H. E., Luke, M., Maciel, A., Majumder, G., Maksimovic, P., Martin, M., Menary, S., Nason, P., Nierste, U., Nir, Y., Nogach, L., Norrbin, E., Oleari, C., Papadimitriou, V., Paulini, M., Paus, C., Petteni, M., Poling, R., Procario, M., Punzi, G., Quinn, H., Rakitine, A., Ridolfi, G., Shestermanov, K., Signorelli, G., Silva, J. P., Skwarnicki, T., Smith, A., Speakman, B., Stenson, K., Stichelbaut, F., Stone, S., Sumorok, K., Tanaka, M., Taylor, W., Trischuk, W., Tseng, J., Van Kooten, R., Vasiliev, A., Voloshin, M., Wang, J. C., Wicklund, A. B., Wurthwein, F., Xuan, N., Yarba, J., Yip, K., and Zieminski, A.
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
This report provides a comprehensive overview of the prospects for B physics at the Tevatron. The work was carried out during a series of workshops starting in September 1999. There were four working groups: 1) CP Violation, 2) Rare and Semileptonic Decays, 3) Mixing and Lifetimes, 4) Production, Fragmentation and Spectroscopy. The report also includes introductory chapters on theoretical and experimental tools emphasizing aspects of B physics specific to hadron colliders, as well as overviews of the CDF, D0, and BTeV detectors, and a Summary., Comment: 583 pages. Further information on the workshops, including transparencies, can be found at the workshop's homepage: http://www-theory.lbl.gov/Brun2/. The report is also available in 2-up http://www-theory.lbl.gov/Brun2/report/report2.ps.gz or chapter-by-chapter http://www-theory.lbl.gov/Brun2/report/
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- 2002
164. Application of heavy-quark effective theory to lattice QCD: III. Radiative corrections to heavy-heavy currents
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Harada, Junpei, Hashimoto, Shoji, Kronfeld, Andreas S., and Onogi, Tetsuya
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High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
We apply heavy-quark effective theory (HQET) to separate long- and short-distance effects of heavy quarks in lattice gauge theory. In this paper we focus on flavor-changing currents that mediate transitions from one heavy flavor to another. We stress differences in the formalism for heavy-light currents, which are discussed in a companion paper, showing how HQET provides a systematic matching procedure. We obtain one-loop results for the matching factors of lattice currents, needed for heavy-quark phenomenology, such as the calculation of zero-recoil form factors for the semileptonic decays $B\to D^{(*)}l\nu$. Results for the Brodsky-Lepage-Mackenzie scale $q^*$ are also given., Comment: 35 pages, 17 figures. Program LatHQ2QCD to compute matching one-loop coefficients available at http://theory.fnal.gov/people/kronfeld/LatHQ2QCD/
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- 2001
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165. Application of heavy-quark effective theory to lattice QCD: II. Radiative corrections to heavy-light currents
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Harada, Junpei, Hashimoto, Shoji, Ishikawa, Ken-Ichi, Kronfeld, Andreas S., Onogi, Tetsuya, and Yamada, Norikazu
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High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
We apply heavy-quark effective theory to separate long- and short-distance effects of heavy quarks in lattice gauge theory. In this approach, the inverse heavy-quark mass and the lattice spacing are treated as short distances, and their effects are lumped into short-distance coefficients. We show how to use this formalism to match lattice gauge theory to continuum QCD, order by order in the heavy-quark expansion. In this paper, we focus on heavy-light currents. In particular, we obtain one-loop results for the matching factors of lattice currents, needed for heavy-quark phenomenology, such as the calculation of heavy-light decay constants, and heavy-to-light transition form factors. Results for the Brodsky-Lepage-Mackenzie scale $q^*$ are also given., Comment: 32 pages, 8 figures. v2 corrects Eqs. (4.9) and (4.10) and adds a reference. Program LatHQ2QCD to compute matching one-loop coefficients available at http://theory.fnal.gov/people/kronfeld/LatHQ2QCD/
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- 2001
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166. Lattice QCD and the Unitarity Triangle
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Kronfeld, Andreas S.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
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 -> pi l nu and B -> D* l nu, as well as the parameter \xi in B-Bbar mixing, are highlighted., Comment: Invited talk at the 9th International Symposium on Heavy Flavor Physics, September 10-13, 2001, Caltech, Pasadena. 11 pages, 5 figures
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- 2001
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167. The anti-B --> D* lepton anti-neutrino form factor at zero recoil and the determination of V(cb)
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Simone, J. N., Hashimoto, S., Kronfeld, A. S., Mackenzie, P. B., and Ryan, S. M.
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High Energy Physics - Lattice - Abstract
We summarize our lattice QCD study of the form factor at zero recoil in the decay anti-B --> D* lepton anti-neutrino. After careful consideration of all sources of systematic uncertainty, we find, h_A1(1) = 0.913(+0.024-0.017)(+0.017-0.030), where the first uncertainty is from statistics and fitting while the second combined uncertainty is from all other systematic effects., Comment: Lattice2001(HeavyQuark); 3 pages, 2 eps figures, espcrc2.sty
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- 2001
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168. Lattice calculation of the zero-recoil form factor of anti-B --> D* lepton anti-neutrino: toward a model independent determination of |V(cb)
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Hashimoto, Shoji, Kronfeld, Andreas S., Mackenzie, Paul B., Ryan, Sinead M., and Simone, James N.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
We develop a new method in lattice QCD to calculate the form factor F(1) at zero recoil. This is the main theoretical ingredient needed to determine |V(cb)| from the exclusive decay anti-B --> D* lepton anti-neutrino. We introduce three ratios, in which most of statistical and systematic error cancels, making a precise calculation possible. We fit the heavy-quark mass dependence directly, and extract the 1/m_Q^2 and three of the four 1/m_Q^3 corrections in the heavy-quark expansion. In this paper we show how the method works in the quenched approximation, obtaining F(1) = 0.913 (+0.024-0.017)(+/-0.016)(+0.003-0.014)(+0.000-0.016)(+0.006-0.014) where the uncertainties come, respectively, from statistics and fitting, matching lattice gauge theory to QCD, lattice spacing dependence, light quark mass effects, and the quenched approximation. We also discuss how to reduce these uncertainties and, thus, to obtain a model-independent determination of |V(cb)|., Comment: 31 pages, 9 eps figures, RevTeX; PACS numbers: 12.38.Gc, 12.15.Hh, 13.20.He
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- 2001
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169. One-loop renormalization of heavy-light currents
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Harada, J., Hashimoto, S., Ishikawa, K. -I., Kronfeld, A. S., Onogi, T., and Yamada, N.
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High Energy Physics - Lattice - Abstract
We calculate the mass dependent renormalization factors of heavy-light bilinears at one-loop order of perturbation theory, when the heavy quark is treated with the Fermilab formalism. We present numerical results for the Wilson and Sheikholeslami-Wohlert actions, with and without tree-level rotation. We find that in both cases our results smoothly interpolate from the static limit to the massless limit. We also calculate the mass dependent Brodsky-Lepage-Mackenzie scale $q^*$, with and without tadpole-improvement., Comment: Lattice2001(improvement), 3 pages, 4 figures
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- 2001
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170. Linear Collider Physics
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Derwent, Paul F., Dobrescu, Bogdan A., Kronfeld, Andreas S., Logan, Heather E., Matchev, Konstantin T., Para, Adam, Rainwater, David L., Tkaczyk, Slawomir, and Wester III, William C.
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High Energy Physics - Experiment ,High Energy Physics - Phenomenology ,Physics - Accelerator Physics - Abstract
We report on a study of the physics potential of linear $e^+e^-$ colliders. Although a linear collider (LC) would support a broad physics program, we focus on the contributions that could help elucidate the origin of electroweak symmetry breaking. Many extensions of the standard model have a decoupling limit, with a Higgs boson similar to the standard one and other, higher-mass states. Mindful of such possibilities, we survey the physics of a (nearly) standard Higgs boson, as a function of its mass. We also review how measurements from an LC could help verify several well-motivated extensions of the standard model. For supersymmetry, we compare the strengths of an LC with the LHC. Also, assuming the lightest superpartner explains the missing dark matter in the universe, we examine other places to search for a signal of supersymmetry. We compare the signatures of several scenarios with extra spatial dimensions. We also explore the possibility that the Higgs is a composite, concentrating on models that (unlike technicolor) have a Higgs boson with mass of a few hundred GeV or less. Where appropriate, we mention the importance of high luminosity, for example to measure branching ratios of the Higgs, and the importance of multi-TeV energies, for example to explore the full spectrum of superpartners., Comment: 58 pp. Report prepared for Fermilab Directorate
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- 2001
171. O(a)-improved quark action on anisotropic lattices and perturbative renormalization of heavy-light currents
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Harada, Junpei, Kronfeld, Andreas S., Matsufuru, Hideo, Nakajima, Noriaki, and Onogi, Tetsuya
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High Energy Physics - Lattice - Abstract
We investigate the Symanzik improvement of the Wilson quark action on anisotropic lattices. Taking first a general action with nearest-neighbor and clover interactions, we study the mass dependence of the ratio of the hopping parameters, the clover coefficients, and an improvement coefficient for heavy-light vector and axial vector currents. We show how tree-level improvement can be achieved. For a particular choice of the spatial Wilson coupling, the results simplify, and $O(m_0a_\tau)$ improvement is possible. (Here $m_0$ is the bare quark mass and $a_\tau$ the temporal lattice spacing.) With this choice we calculate the renormalization factors of heavy-light bilinear operators at one-loop order of perturbation theory employing the standard plaquette gauge action., Comment: 26 pages, 8 figures
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- 2001
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172. The Semileptonic Decays $B\to\pi l\nu$ and $D\to\pi l\nu$ from Lattice QCD
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El-Khadra, Aida X., Kronfeld, Andreas S., Mackenzie, Paul B., Ryan, Sinead M., and Simone, James N.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
We present a lattice QCD calculation of the form factors and differential decay rates for semileptonic decays of the heavy-light mesons $B$ and $D$ to the final state $\pi l\nu$. The results are obtained with three methodological improvements over previous lattice calculations: a matching procedure that reduces heavy-quark lattice artifacts, the first study of lattice-spacing dependence, and the introduction of kinematic cuts to reduce model dependence. We show that the main systematics are controllable (within the quenched approximation) and outline how the calculations could be improved to aid current experiments in the determination of~$|V_{ub}|$ and~$|V_{cd}|$., Comment: 35 pp, 12 figs
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- 2001
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173. B and D Mesons in Lattice QCD
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Kronfeld, Andreas S.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
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_1; form factors needed to determine |V_{cb}| and |V_{ub}|; bag parameters for the mass differences of the B mesons; and decay constants. Prospects for removing the quenched approximation are discussed., Comment: Mini-review from the XXXth International Conference on High Energy Physics, Osaka, Japan
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- 2000
174. Computation of $\bar{\Lambda}$ and $\lambda_1$ with Lattice QCD
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Kronfeld, Andreas S. and Simone, James N.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
We pursue a new method, based on lattice QCD, for determining the quantities $\bar{\Lambda}$, $\lambda_1$, and $\lambda_2$ of heavy-quark effective theory. We combine Monte Carlo data for the meson mass spectrum with perturbative calculations of the short-distance behavior, to extract $\bar{\Lambda}$ and $\lambda_1$ from a formula from HQET. Taking into account uncertainties from fitting the mass dependence and from taking the continuum limit, we find $\bar{\Lambda} = 0.68{+0.02}_{-0.12} \text{GeV}$ and $\lambda_1 = -(0.45 \pm 0.12) \text{GeV}^2$ in the quenched approximation., Comment: 7 pp, 4 figs (in v2 Fig. 4 now shows Ref. 13, as advertised); in v3 error in BLM scale is corrected
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- 2000
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175. Application of heavy-quark effective theory to lattice QCD: I. Power Corrections
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Kronfeld, Andreas S.
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High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
Heavy-quark effective theory (HQET) is applied to lattice QCD with Wilson fermions at fixed lattice spacing a. This description is possible because heavy-quark symmetries are respected. It is desirable because the ultraviolet cutoff $1/a$ in current numerical work and the heavy-quark mass $m_Q$ are comparable. Effects of both short distances, a and $1/m_Q$, are captured fully into coefficient functions, which multiply the operators of the usual HQET. Standard tools of HQET are used to develop heavy-quark expansions of lattice observables and, thus, to propagate heavy-quark discretization errors. Three explicit examples are given: namely, the mass, decay constant, and semileptonic form factors of heavy-light mesons., Comment: 41 pp., no figs; Phys Rev D version, improving argument that an HQET holds for all m_Qa
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- 2000
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176. The B -> D* l nu Form Factor at Zero Recoil
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Simone, J. N., Hashimoto, S., El-Khadra, A. X., Kronfeld, A. S., Mackenzie, P. B., and Ryan, S. M.
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High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
We describe a model independent lattice QCD method for determining the deviation from unity for h_{A1}(1), the B -> D* l nu form factor at zero recoil. We extend the double ratio method previously used to determine the B -> D l nu form factor. The bulk of statistical and systematic errors cancel in the double ratios we consider, yielding form factors which promise to reduce present theoretical uncertainties in the determination of V_{cb}. We present results from a prototype calculation at a single lattice spacing corresponding to beta=5.7., Comment: Lattice99(heavyquarks); 3 pgs, LaTeX
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- 1999
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177. B and D semileptonic decays to light mesons
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Ryan, Sinead M., El-Khadra, Aida X., Kronfeld, Andreas S., Mackenzie, Paul B., and Simone, James N.
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High Energy Physics - Lattice - Abstract
We present an update of our calculation of the form factors and partial widths of semileptonic heavy-to-light meson decays, in the quenched approximation. Our complete data set has now been analysed and our results include chiral extrapolations and a study of the lattice spacing dependence., Comment: LATTICE99(Heavy Quarks), 3 pages, uses espcrc2.sty
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- 1999
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178. Perturbative and Non-perturbative Corrections to $B\to D^{(*)}l\nu$
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Kronfeld, Andreas S.
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High Energy Physics - Lattice - Abstract
It is shown that certain double ratios introduced for computing semileptonic form factors are accurate to order $1/m_Q^2$, even when the action and current are accurate to order $1/m_Q$., Comment: Lattice99(heavyquarks); 3 + epsilon pp. LaTeX
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- 1999
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179. Lattice QCD calculation of $\bar{B}\to Dl\bar{\nu}$ decay form factors at zero recoil
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Hashimoto, Shoji, El-Khadra, Aida X., Kronfeld, Andreas S., Mackenzie, Paul B., Ryan, Sinead M., and Simone, James N.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
A lattice QCD calculation of the $\bar{B}\to Dl\bar{\nu}$ decay form factors is presented. We obtain the value of the form factor $h_+(w)$ at the zero-recoil limit $w=1$ with high precision by considering a ratio of correlation functions in which the bulk of the uncertainties cancels. The other form factor $h_-(w)$ is calculated, for small recoil momenta, from a similar ratio. In both cases, the heavy quark mass dependence is observed through direct calculations with several combinations of initial and final heavy quark masses. Our results are $h_+(1) = 1.007(6)(2)(3)$ and $h_-(1)=-0.107(28)(04)(^{10}_{30})$. For both the first error is statistical, the second stems from the uncertainty in adjusting the heavy quark masses, and the last from omitted radiative corrections. Combining these results, we obtain a precise determination of the physical combination $F_{B\to D}(1)=1.058(^{20}_{17})$, where the mentioned systematic errors are added in quadrature. The dependence on lattice spacing and the effect of quenching are not yet included, but with our method they should be a fraction of $F_{B\to D}-1$., Comment: 32 pp, 10 figs; final, published version
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- 1999
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180. Lattice QCD Calculations of Leptonic and Semileptonic Decays
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Kronfeld, Andreas S.
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
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., Comment: Invited talk at the Workshop on Heavy Quarks at Fixed Target, October 10-12, 1998, Fermi National Accelerator Laboratory
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- 1998
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181. B -> D l nu form factors and the determination of |Vcb
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Hashimoto, S., El-Khadra, A. X., Kronfeld, A. S., Mackenzie, P. B., Ryan, S. M., and Simone, J. N.
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High Energy Physics - Lattice - Abstract
The zero recoil limit of the B -> D l nu form factors is calculated on the lattice, which provides a model-independent determination of |Vcb|. Considering a ratio of form factors, in which the bulk of statistical and systematic errors cancel, we obtain a precise result both for h_+(1) and for h_-(1)., Comment: LATTICE98(heavyqk), LaTeX, 3 pages, 3 postscript figures, uses espcrc2.sty
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- 1998
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182. Renormalization of Currents for Massive Fermions
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Kronfeld, A. S. and Hashimoto, S.
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High Energy Physics - Lattice - Abstract
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., Comment: LATTICE98(heavyqk), LaTeX, 3 pages, 3 postscript figures, uses espcrc2.sty; version2 adds hep-lat links for refs 1 and 8
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- 1998
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183. Estimated Errors in |Vcd|/|Vcs| from Semileptonic D Decays
- Author
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Simone, J. N., El-Khadra, A. X., Hashimoto, S., Kronfeld, A. S., Mackenzie, P. B., and Ryan, S. M.
- Subjects
High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
We estimate statistical and systematic errors in the extraction of the CKM ratio |Vcd|/|Vcs| from exclusive D-meson semileptonic decays using lattice QCD and anticipated new experimental results., Comment: LATTICE98(heavyqk), LaTeX, 3 pages, 2 postscript figures, uses espcrc2.sty and hyperbasics.tex
- Published
- 1998
- Full Text
- View/download PDF
184. B -> pi l nu at three lattice spacings
- Author
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Ryan, S. M., El-Khadra, A. X., Hashimoto, S., Kronfeld, A. S., Mackenzie, P. B., and Simone, J. N.
- Subjects
High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
The increasing accuracy of experimental results for the exclusive, semileptonic decay B -> pi l nu requires a similarly accurate calculation of the hadronic matrix elements, to determine |Vub|. We present preliminary results for the form factors of the B to light meson decay mode. Using results from three lattices in the range 5.7 <= beta <= 6.1 we study the dependence on the lattice spacing., Comment: LATTICE98(heavyqk), LaTeX, 3 pages, 4 postscript figures, uses espcrc2.sty
- Published
- 1998
- Full Text
- View/download PDF
185. Three Electroweak Results from Lattice QCD
- Author
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Kronfeld, Andreas S.
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
Quantum chromodynamics is needed to understand quarks and, hence, to determine the quarks' Yukawa couplings from experimental measurements. As a short illustration, the results of three lattice calculations are given., Comment: 4 pp; talk presented at the XXXIIIrd Rencontres de Moriond on Electroweak Interactions and Unified Theories, 14-21 March 1998, Les Arcs, France
- Published
- 1998
186. The Perturbative Pole Mass in QCD
- Author
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Kronfeld, Andreas S.
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
It is widely believed that the pole mass of a quark is infrared-finite and gauge-independent to all orders in perturbation theory. This seems not to have been proved in the literature. A proof is provided here., Comment: 12 pages REVTeX with 2 figures; archiving published version with note and references added. If you thought this was proven long ago see http://www-theory.fnal.gov/people/ask/TeX/mPole/
- Published
- 1998
- Full Text
- View/download PDF
187. The Self-Energy of Massive Lattice Fermions
- Author
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Mertens, Bartholomeus P. G., Kronfeld, Andreas S., and El-Khadra, Aida X.
- Subjects
High Energy Physics - Lattice - Abstract
We address the perturbative renormalization of massive lattice fermions. We derive expressions-valid to all orders in perturbation theory and for all values of the bare fermion mass-for the rest mass, the kinetic mass, and the wave-function renormalization factor. We obtain the fermion's self energy at the one-loop level with a mass-dependent, $O(a)$ improved action. Numerical results for two interesting special cases, the Wilson and Sheikholeslami-Wohlert actions, are given. The mass dependence of these results smoothly connects the massless and infinite-mass limits, as expected. Combined with Monte Carlo calculations our results can be employed to determine the quark masses in common renormalization schemes., Comment: 33 pages; 11 figures (included)
- Published
- 1997
- Full Text
- View/download PDF
188. B and D Meson Decay Constants in Lattice QCD
- Author
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El-Khadra, Aida X., Kronfeld, Andreas S., Mackenzie, Paul B., Ryan, Sinead M., and Simone, James N.
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
We have calculated the decay constants of B and $D$ mesons with lattice QCD. We use an $O(a)$ improved action that takes light quark actions as a starting point, tuned so that it can be directly applied at the physical masses of the $b$ and $c$ quarks. Our results are $f_B = 164 \err{+14}{-11} \pm 8$ MeV, $f_{B_s} = 185 \err{+13}{-8} \pm 9$ MeV, $f_D = 194 \err{+14}{-10} \pm 10$ MeV, and $f_{D_s} = 213 \err{+14}{-11} \pm 11$ MeV in the quenched approximation. The first error in each case is statistical, and the second is from perturbation theory. We show that discretization errors are under control in our approach, and smaller than our statistical errors. The effects of the quenched approximation may raise our quenched result by up to 10%., Comment: 21 pages, 6 figures
- Published
- 1997
- Full Text
- View/download PDF
189. The Charm Quarks's Mass
- Author
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Kronfeld, Andreas S.
- Subjects
High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
The charm quark's mass is determined from Monte Carlo calculations of the $\bar{c}c$ spectrum. The main sources of uncertainty are perturbation theory (for conversion to $\MSbar$), the continuum-limit extrapolation, Monte Carlo statistics, and the effects of quenching. The (preliminary) result for the $\MSbar$ mass is $\bar{m}_{ch}(m_{ch})=1.33\pm 0.08$ GeV., Comment: contribution to LATTICE 97(HEAVY QUARKS); 3 pp., 1 fig
- Published
- 1997
- Full Text
- View/download PDF
190. The Light Quark Masses from Lattice Gauge Theory
- Author
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Gough, Brian J., Hockney, George M., El-Khadra, Aida X., Kronfeld, Andreas S., Mackenzie, Paul B., Mertens, Bart P., Onogi, Tetsuya, and Simone, James N.
- Subjects
High Energy Physics - Phenomenology - Abstract
We investigate the masses of the light quarks with lattice QCD. We show that most of the large dependence on the lattice spacing, a, observed in previous determinations using Wilson fermions is removed with the use of an O(a) corrected action. In the quenched approximation, we obtain for the strange quark MS bar mass m_s(2 GeV) = 95 (16) MeV, and for the average of the up and down quark masses m_l(2 GeV) = 3.6 (6) MeV. Short distance arguments and existing staggered fermion calculations make it likely that the answers including the effects of quark loops lie 20 % to 40 % below this: m_s(2 GeV) in the range 54-92 MeV, and m_l(2 GeV) in the range 2.1-3.5 MeV. We argue that almost all lattice determinations of the light quark masses are consistent with these values. These low values are outside the range usually given by conventional phenomenology., Comment: 4 pages, two embedded figures
- Published
- 1996
- Full Text
- View/download PDF
191. Light Quark Masses with an O(a)-Improved Action
- Author
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Onogi, T., El-Khadra, A. X., Gough, B. J., Hockney, G. M., Kronfeld, A. S., Mackenzie, P. B., Mertens, B. P., and Simone, J. N.
- Subjects
High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
We present the recent Fermilab calculations of the masses of the light quarks, using tadpole-improved Sheikholeslami-Wohlert (SW) quarks. Various sources of systematic errors are studied. Our final result for the average light quark mass in the quenched approximation evaluated in the $\bar{MS}$ scheme is $\bar{m}_q(\mu=2 GeV;n_f=0)= (m_u+m_d)/2=3.6 \pm 0.6 MeV$., Comment: 3 pgs. 3 figures. espcrc2.sty included. Talk presented at LATTICE96(phenomenology)
- Published
- 1996
- Full Text
- View/download PDF
192. Binding Energies in Nonrelativistic Field Theories
- Author
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Kronfeld, Andreas S.
- Subjects
High Energy Physics - Lattice - Abstract
Relativistic corrections communicate the binding energy of a bound state to its kinetic mass. This mechanism is reviewed and used to explain anomalous results of Collins, Edwards, Heller, and Sloan (hep-lat/9512026), which compared rest and kinetic masses of heavy-light mesons and quarkonia., Comment: 4 pages, 1 figure, poster presented at LATTICE96(heavy quarks)
- Published
- 1996
- Full Text
- View/download PDF
193. Massive Fermions in Lattice Gauge Theory
- Author
-
El-Khadra, Aida X., Kronfeld, Andreas S., and Mackenzie, Paul B.
- Subjects
High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
This paper presents a formulation of lattice fermions applicable to all quark masses, large and small. We incorporate interactions from previous light-fermion and heavy-fermion methods, and thus ensure a smooth connection to these limiting cases. The couplings in improved actions are evaluated for arbitrary fermion mass~$m_q$, without expansions around small- or large-mass limits. We treat both the action and external currents. By interpreting on-shell improvement criteria through the lattice theory's Hamiltonian, one finds that cutoff artifacts factorize into the form $b_n(m_qa)[\vek{p}a]^{s_n}$, where $\vek{p}$ is a momentum characteristic of the system under study, $s_n$ is related to the dimension of the $n$th interaction, and $b_n(m_qa)$ is a bounded function, numerically always~$\order(1)$ or less. In heavy-quark systems $\vek{p}$ is typically rather smaller than the fermion mass~$m_q$. Therefore, artifacts of order $(m_qa)^s$ do not arise, even when $m_qa\gsim1$. An important by-product of our analysis is an interpretation of the Wilson and Sheikholeslami-Wohlert actions applied to nonrelativistic fermions., Comment: 54 pages; 5 files for figures, 4 for tables, 2 for macros (all included); PostScript also at http://www-theory.fnal.gov/people/ask/TeX/heavy/theory.ps.gz
- Published
- 1996
- Full Text
- View/download PDF
194. Desperately Seeking Chiral Fermions
- Author
-
Kronfeld, Andreas S.
- Subjects
High Energy Physics - Lattice - Abstract
Chiral fermions can (presumably) be constructed by introducing two regulators, one for the gauge fields (e.g. a lattice), and another for the fermion functional integrals in a fixed (regulated) gauge field. This talk discusses cutoff effects arising from the regulator of the fermions., Comment: 4 pages, contribution to Lattice '95 Postscript at http://www-theory.fnal.gov/people/ask/TeX/lat95/chiral.ps
- Published
- 1996
- Full Text
- View/download PDF
195. Chiral Fermions Coupled to Lattice Gauge Fields
- Author
-
Kronfeld, Andreas S.
- Subjects
High Energy Physics - Lattice ,High Energy Physics - Phenomenology ,High Energy Physics - Theory - Abstract
Lattice fermions have well-known difficulties with chiral symmetry. To evade them it is possible to couple continuum fermions to lattice gauge fields, by introducing an interpolation of the latter. Following this line of thinking, this paper presents two Euclidean formulations of the effective action that appears after functional integration over fermion fields, one for vector-like and the other for chiral couplings. With suitable finite-mode regulators both effective actions can be evaluated in a finite computation. The prescriptions provided here contain some details not found in previous work marrying continuum fermions to the lattice via an interpolation. For example, the counter-terms needed to maintain chiral gauge invariance are explicitly given. By construction coupling-constant renormalization, anomaly structure, and (in the chiral gauge theory) fermion nonconserving amplitudes all satisfy one's expectations from perturbative and semi-classical analyses., Comment: 1 (title) + 28 pages, LaTeX; 1 figure embedded with epsf and posted separately; also available at ftp://fnth06.fnal.gov/pub/Fermilab-Pub/95.073 one concluding paragraph and several references added
- Published
- 1995
196. LATTICE QCD AND THE STANDARD MODEL
- Author
-
Kronfeld, Andreas S.
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
Most of the poorly known parameters of the Standard Model cannot be determined without reliable calculations in nonperturbative QCD. Lattice gauge theory provides a first-principles definition of the required functional integrals, and hence offers ways of performing these calculations. This paper reviews the progress in computing hadron spectra and electroweak matrix elements needed to determine $\alpha_S$, the quark masses, and the Cabibbo-Kobayashi-Maskawa matrix., Comment: 1 (title) + 21 pages, LaTeX; style-file, .aux file, and figures wrapped with uufiles; also at ftp://fnth06.fnal.gov/pub/Fermilab-Pub/95.067 presented at the Seventh Adriatic Meeting on Particle Physics, Brijuni, Croatia, 13--20 September 1994
- Published
- 1995
- Full Text
- View/download PDF
197. Improved Currents for Heavy Quarks
- Author
-
Kronfeld, Andreas S. and Fermilab
- Subjects
High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
We discuss lattice artifacts for matrix elements of hadrons containing one or more heavy quark. In particular, we analyze interrelations between lattice artifacts and the $1/m_Q$ expansion. The implications for calculations of heavy-light decay constants and of semi-leptonic form factors are discussed., Comment: 3 pages, no figures, uuencoded PostScript, proceedings of Lattice '94. LaTeX at ftp://fnth06.fnal.gov/pub/Fermilab-Pub/95.002
- Published
- 1995
- Full Text
- View/download PDF
198. Renormalization of Massive Lattice Fermions
- Author
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Kronfeld, A. S. and Mertens, B. P.
- Subjects
High Energy Physics - Lattice - Abstract
The renormalization of a general action for massive lattice fermions is discussed. The analysis applies for all $m_q a$. Preliminary results for the self energy at one loop in perturbation theory are presented., Comment: 3 pages (you guessed it: to appear in Lattice '93), uuencoded PostScript file, FERMILAB-CONF-93/382-T and EFI 93-72. Regular PostScript file by anonymous ftp to fnth06.fnal.gov as pub/Fermilab-Pub/93.382
- Published
- 1993
- Full Text
- View/download PDF
199. Beauty and the Beast: What Lattice QCD Can Do for $B$ Physics
- Author
-
Kronfeld, Andreas S.
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
The role lattice QCD can play in $B$ physics is surveyed. We include results for the decay constant, and discuss upcoming calculations of semileptonic form factors and neutral-meson mixing. Together with experimental measurements, these calculations can determine the unitarity triangle. Plenary talk presented at the Workshop on $B$ Physics at Hadron Accelerators, Snowmass, Colo., 21 June--2 July, 1993., Comment: FERMILAB-CONF-93/277-T, 17 pages, uucompressed PostScript file: unpack and print. Errors in bibliography corrected
- Published
- 1993
200. QCD results for nucleon Compton scattering
- Author
-
Kronfeld, A. S. and Nizic, B.
- Subjects
High Energy Physics - Phenomenology - Abstract
We present QCD results for the exclusive processes $\gamma{\rm N}\rightarrow\gamma{\rm N}$ ($\rm N=p,\;n$) at large momentum transfer and compare them to data for the proton. TALK given at DPF meeting, November 10-14, Fermilab., Comment: 3 pages; FERMILAB-CONF-92/332-T; uuencoded
- Published
- 1992
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