Matching of the Heavy-Light Currents with NRQCD Heavy and Improved Naive Light Quarks

One-loop matching of heavy-light currents is carried out for a highly improved lattice action, including the effects of mixings with dimension 4 O(1/M) and O(a) operators. We use the NRQCD action for heavy quarks, the Asqtad improved naive action for light quarks, and the Symanzik improved glue action. These results are being used in recent heavy meson decay constant and semileptonic form factor calculations on the MILC dynamical configurations.Comment: 3 pages, 3 figures. Talk presented at Lattice2004(heavy

B Leptonic Decays and B- bar B Mixing with 2+1 Flavors of Dynamical Quarks

Calculations of B leptonic decays and B- bar B mixing using NRQCD heavy and Asqtad light valence quarks on the MILC dynamical configurations are described. Smearing has been implemented to substantially reduce the statistical errors of the matrix elements needed for the determination of f_B. The four-fermion matrix elements needed for the determination of f_{B_s}^2B_{B_s} have been calculated and a preliminary result is given.Comment: 3 pages, 3 figures, talk given at Lattice2004(heavy), Batavia, Illinois, 21-26 Jun 200

Aristotle on Self-Sufficiency, External Goods, and Contemplation

Aristotle tells us that contemplation is the most self-sufficient form of virtuous activity: we can contemplate alone, and with minimal resources, while moral virtues like courage require other individuals to be courageous towards, or courageous with. This is hard to square with the rest of his discussion of self-sufficiency in the Ethics: Aristotle doesn't generally seek to minimize the number of resources necessary for a flourishing human life, and seems happy to grant that such a life will be self-sufficient despite requiring a lot of external goods. In this paper I develop an interpretation of self-sufficiency as a form of independence from external contributors to our activity, and argue that this interpretation accounts both for Aristotle's views on contemplation and for the role self-sufficiency plays in his broader account of human happiness

Light quark masses from quenched lattice QCD simulations with domain wall quarks

Values for the strange quark mass and average up/down mass have been obtained from quenched lattice QCD simulations using the domain wall fermion action. This discretization preserves the properties of flavor and chiral symmetry at nonzero lattice spacing. Results are shown for two values of the lattice spacing. The mass renormalization constant is computed nonperturbatively.Comment: To appear in the proceedings of DPF 2000, Columbus, OH, USA. Work done as part of the RIKEN/BNL/Columbia Collaboration. (3 pages

B_s Mesons using Staggered Light Quarks

Last year we proposed using staggered fermions as the light quarks, combined with nonrelativistic heavy quarks, in simulations of heavy-light mesons. A first round of tests which focuses on the B_s meson has been completed using quenched lattices, and results are presented here for the kinetic B_s mass, the B_s^* - B_s splitting, and f_{B_s}. The next project, already underway, is to compute the B and B_s decay constants and spectra on the n_f = 2+1 and 3 MILC lattices. We report on progress with one set of these configurations.Comment: Talk presented by M.W. at Lattice2002(heavyquark

B Decays on the Lattice and Results for Phenomenology

Lattice Monte Carlo simulations now include the effects of 2 light sea quarks and 1 strange sea quark through the use of an improved staggered fermion action. Consequently, results important to phenomenology are free of the approximate 10% errors inherent in the quenched approximation. This talk reports on calculations of the B and Bs decay constants and B -> pi l nu form factors. Accurate determinations of these quantities will lead to tighter constraints on CKM matrix elements.Comment: Contributed to the Proceedings of American Physical Society's 2004 Meeting of the Division of Particles and Fields (DPF2004), Riverside, CA, 26-31 August 2004. 3 page