118595631
Charm semileptonic decays and|Vcs(d) from heavy clover quarks and 2+1 flavor asqtad staggered ensembles
By combining experimentally measured partial branching fractions for the semileptonic decays D→Klν and D→ πlν with lattice calculations of the form factors f D→K + (q2) and f D→π + (q2), one can extract the CKM matrix elements |Vcs| and |Vcd |. We are calculating the form factors by using Fermilab charm and asqtad staggered light and strange quarks on 2+1 flavor asqtad staggered ensembles generated by the MILC Collaboration. We vary the light valence quark masses from 0.4ms to 0.05ms (ms is the strange sea-quark mass), and the lattice spacings, from about 0.12 fm to about 0.045 fm. We extrapolate to the physical light-quark mass and the continuum limit using heavy-light meson staggered chiral perturbation theory about the SU(2) and SU(3) limits, compare the resulting (preliminary) form factor shapes with experiment, and discuss our errors.
118670651
$D$ semileptonic form factors and $|V_{cs(d)}|$ from 2+1 flavor lattice QCD
The measured partial widths of the semileptonic decays D {yields} K{ell}{nu} and D {yields} {pi}{ell}{nu} can be combined with the form factors calculated on the lattice to extract the CKM matrix elements |V{sub cs}| and |V{sub cd}|. The lattice calculations can be checked by comparing the form factor shapes from the lattice and experiment. We have generated a sizable data set by using heavy clover quarks with the Fermilab interpretation for charm and asqtad staggered light quarks on 2+1 flavor MILC ensembles with lattice spacings of approximately 0.12, 0.09, 0.06, and 0.045 fm. Preliminary fits to staggered chiral perturbation theory suggest that we can reduce the uncertainties in the form factors at q{sup 2} = 0 to below 5%.
15857007
Unitarity and the heavy quark expansion in the determination of semileptonic form factors
We discuss prospects for improving the q 2 extrapolation of the B → πlν form factors with model-independent constraints based on unitarity and heavy quark power-counting. As an illustration, we apply the method to preliminary results of calculations of the form factors, which we generated using the MILC gauge configurations and the Fermilab action for the heavy b-quark. Unitarity, the heavy quark expansion, and semileptonic form factors Ruth S. Van de Water
7429466
Light pseudoscalar meson masses and decay constants from mixed action lattice QCD
We calculate the light pseudoscalar decay constants, f_pi and f_K, and their ratio using domain wall valence quarks and 2+1 flavors of dynamical staggered quarks. Use of the MILC gauge configurations allows us to simulate at several sea quark masses and spatial volumes, and with two lattice spacings. We study how well our numerical lattice data for light decay constants and meson masses is described by next-to-leading order SU(3) mixed action chiral perturbation theory and explain our strategy for the chiral and continuum extrapolation. Combining our result for f_K/f_pi with experimental measurements of pion and kaon leptonic decays allows a model-independent determination of |V_us|/|V_ud|; we find a preliminary value of |V_us|/|V_ud| = 0.2315(45)(7).
35146463
Neutral kaon mixing parameter BK from unquenched mixed-action lattice QCD
We calculate the neutral kaon mixing parameter B_K in unquenched lattice QCD using asqtad-improved staggered sea quarks and domain-wall valence quarks. We use the "2+1" flavor gauge configurations generated by the MILC Collaboration, and simulate with multiple valence and sea quark masses at two lattice spacings of a ~ 0.12 fm and a ~ 0.09 fm. We match the lattice determination of B_K to the continuum value using the nonperturbative method of Rome-Southampton, and extrapolate B_K to the continuum and physical quark masses using mixed action chiral perturbation theory. The "mixed-action" method enables us to control all sources of systematic uncertainty and therefore to precisely determine B_K; we find a value of B_K^{MSbar, NDR}(2 GeV) = 0.527(6)(20), where the first error is statistical and the second is systematic.
119241694
Matrix Elements for D- and B-Mixing from 2+1 Flavor Lattice QCD
C.C. Chang∗ a f , C. Bernard b, C.M. Bouchard c, A.X. El-Khadra a f , E.D. Freeland d, E. Gamiz e, A.S. Kronfeld f , J. Laiho g, R.S. van de Water f aPhysics Department, University of Illinois, Urbana, IL 61801, USA bDepartment of Physics, Washington University, St. Louis, MO 63130, USA cDepartment of Physics, The Ohio State University, Columbus, OH 43210, USA dLiberal Arts Department, The School of the Art Institute of Chicago, Chicago, IL 60603, USA eCAFPE and Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, E-18002 Granada, Spain fTheoretical Physics Department, Fermi National Accelerator Laboratory†, Batavia, IL 60510, USA gSUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow, G12-8QQ, United Kingdom
122603059
Search for rare B decays
Abstract Using the ARGUS detector at the e + e − storage ring DORIS II at DESY, we have searched for decays b → s gluon through full reconstruction of a whole event. Two B B decays were found with one of B meson decaying into a final state without charmed particles. We also obtained an upper limit of Br (B + → τ + ν τ ) of 1.04% at 90% CL .
123971124
Latest Oscillation Results from SNO
The Sudbury Neutrino Observatory has been successfully taking quality neutrino data for over two years now. This paper reports on analysis of the solar charge current and elastic scattering neutrino fluxes from the first year of pure D2O running. Combined with the SuperK elastic scattering flux, there is strong evidence that solar neutrinos are oscillating, and that predictions of the standard solar model are in good agreement with data.
17420422
Study ofD0 andD+ decays into final states with two or three kaons
Using the ARGUS detector at thee+e− storage ring DORIS II, we have studied Cabibbo-suppressedD0 decay modes resulting in theK+K−π+π− final state and two-bodyD0 decay modes with a ϕ meson in the final state. TheBR(D0→KS0KS0π+π− was measured for the first time. We also present a measurement of theD+→KS0KS0K+ branching ratio. The values are compared with other experimental results and model predictions.
122313771
Evidence for W exchange in charmed baryon decays
Using the detector ARGUS at the e+e− storage ring DORIS II at DESY, we have observed the decays Λc+ → Ξ−K+π+ and Λc+ → Ξ∗0K+ and obtained evidence for the decay Ξc0 → ΛKs0. All three of these decays are of interest as they provide information about W-exchange processes. The products of cross sections and branching ratios for Λc+ → Ξ−K+π+ and Λc+ → Ξ∗0K+ are (1.7±0.3±0.3) pb and (0.6±0.2±0.1) pb, respectively, which implies that (35±17) % of the Ξ−K+π+ final state is generated through a two-body decay via intermediate W-exchange. The product of production cross section and branching ratio for Ξc0 → Λ Ks0 is (2.1 ± 1.0 ± 0.6) pb.
124314895
Investigation of the decays anti-B0 ---> D*+ lepton- anti-neutrino and anti-B ---> D** lepton- anti-neutrino