35,025 research outputs found
Lattice QCD Calculations of Leptonic and Semileptonic Decays
In lattice QCD, obtaining properties of heavy-light mesons has been easier
said than done. Focusing on the 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 Laborator
B and D Mesons in Lattice QCD
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, Japa
Lattice QCD and the Unitarity Triangle
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 figure
Heavy Quarks and Lattice QCD
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.Comment: Lattice2003(plenary), 14 pages, 5 figure
Lattice Gauge Theory and the Origin of Mass
Most of the mass of everyday objects resides in atomic nuclei; the total of
the electrons' mass adds up to less than one part in a thousand. The nuclei are
composed of nucleons---protons and neutrons---whose nuclear binding energy,
though tremendous on a human scale, is small compared to their rest energy. The
nucleons are, in turn, composites of massless gluons and nearly massless
quarks. It is the energy of these confined objects, via , that is
responsible for everyday mass. This article discusses the physics of this
mechanism and the role of lattice gauge theory in establishing its connection
to quantum chromodynamics.Comment: prepared for "100 Years of Subatomic Physics," edited by Ernest
Henley and Stephen Ellis. Submitted version with typos corrected and refs
added. 26 pp., 6 figure
Progress in Lattice QCD
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 FRBT0
Twenty-first Century Lattice Gauge Theory: Results from the QCD Lagrangian
Quantum chromodynamics (QCD) reduces the strong interactions, in all their
variety, to a simple 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 from the QCD Lagrangian. This body of work sheds
light on the origin of hadron masses, its interplay with dynamical symmetry
breaking, as well as on other intriguing features such as the phase structure
of QCD. In addition, nonperturbative QCD is quantitatively important to many
aspects of particle physics (especially the quark flavor sector), nuclear
physics, and astrophysics. This review also surveys some of the most
interesting connections to those subjects.Comment: invited review for Annual Reviews of Nuclear and Particle Science
(2012); 21 pp., 4 tables, 6 figures. v2: Figures 2 and 5 updated; references
added; many minor wording changes and clarifications; conforms closely to
accepted versio
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