209866107
A Study of anti-B0 ---> D*+ lepton- anti-neutrino and B0 anti-B0 mixing using partial D*+ reconstruction
125577598
Measurement of the decay B- ---> D*0 l- anti-neutrino
Abstract Using the ARGUS detector at the e + e − storage ring DORIS II at DESY we have studied the decay B − → D ∗0 l − λ , where l − = e − or μ − , using the D 0 γ and D 0 π 0 decay modes of the D ∗0 meson. B mesons were produced in 209 000 decays of γ (4S). Assuming electron-muon universality, we obtain a value for the branching ratio of BR ( B − → D ∗0 l − λ )= (5.8 ± 1.4 ± 1.3)% .
121188685
Measurement of the decay fractions ofD* mesons
Using the ARGUS detector at the DORIS II electron-positron storage ring at DESY, we have measured BR(D*+→D0π+)=(68.8±2.4±1.3)%, BR(D*+→D+π0)=(31.2±1.1±0.8)%, BR(D*+→D+γ)<5.2% (90%CL), BR(D*0→D0π0)=(59.6±3.5±2.8)%, and BR(D*0→D0γ)=(40.4±3.5±2.8)%, and the mass difference Δm0=m(D*0)−m(D0)=(142.2±0.3±0.2)MeV/c2.
122042804
A Model independent determination of the inclusive semileptonic decay fraction of B mesons
Abstract With the ARGUS detector at the e + e - storage ring DORIS II, we have determined decay fraction and electron momentum spectrum of the inclusive decay mode B → eν X. Usinng lepton tags from the second B meson. in 209 000 γ(4 S ) → B B decays, we could determine the spectrum for all electron momenta p e > 0.6 GeV/ c . Including the small extrapolation to p e > 0, we find the model-independent decay fraction B (B → eν X) = (9.6 ± 0.5 ± 0.4)%. Adding D meson tags, our result is (9.7 ± 0.5 ± 0.4)%.
209962993
Search for neutrinoless tau decays
117873551
ICARUS at FNAL
The INFN and the ICARUS collaboration originally developed the technology of the LAr-TPC. Located the underground LNGS Hall-B, the ICARUS T600 detector has been performed over three years with remarkable detection efficiency featuring a smooth operation, high live time, and high reliability. About 3000 CNGS neutrino events have been collected and are being actively analyzed. ICARUS will now be moved to CERN for an extensive RD the T150 will be located at ~150 m. The T600 will also receive >10^4 nu_e events/year from the off-axis NUMI beam peaked around 1 GeV and exploitable to prepare for the LBNE experiment. The ICARUS teams are also interested in extending the participation to other short baseline neutrino activities collaborating with existing FNAL groups.
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%.
11544193
The kaon B-parameter from unquenched mixed action lattice QCD
We present a preliminary calculation of B{sub K} using domain-wall valence quarks and 2+1 flavors of improved staggered sea quarks. Both the size of the residual quark mass, which measures the amount of chiral symmetry breaking, and of the mixed meson splitting Delta{sub mix}, a measure of taste-symmetry breaking, show that discretization effects are under control in our mixed action lattice simulations. We show preliminary data for pseudoscalar meson masses, decay constants and B{sub K}. We discuss general issues associated with the chiral extrapolation of lattice data, and, as an example, present a preliminary chiral and continuum extrapolation of f{sub pi}. The quality of our data shows that the good chiral properties of domain-wall quarks, in combination with the light sea quark masses and multiple lattice spacings available with the MILC staggered configurations, will allow for a precise determination of B{sub K}.
118396661
Discretization effects and the scalar meson correlator in mixed-action lattice simulations
We study discretization effects in a mixed-action lattice theory with domain-wall valence quarks and Asqtad-improved staggered sea quarks. At the level of the chiral effective Lagrangian, discretization effects in the mixed-action theory give rise to two new parameters as compared to the lowest order Lagrangian for rooted-staggered fermions - the residual quark mass m{sub res} and the mixed valence-sea meson mass splitting {delta}{sub mix}. We find that m{sub res}, which parametrizes explicit chiral symmetry breaking in the mixed-action theory, is approximately one-quarter the size of our lightest valence quark mass on our coarser lattice spacing and of comparable size to that of simulations by the RBC and UKQCD Collaborations. We also find that the size of {delta}{sub mix} is comparable to the size of the smallest of the staggered meson taste splittings measured by the MILC Collaboration. Because lattice artifacts are different in the valence and sea sectors of the mixed-action theory, they give rise to unitarity-violating effects that disappear in the continuum limit, some of which should be described by mixed-action chiral perturbation theory (MA{chi}PT). Such effects are expected to be mild for many quantities of interest but are expected to be significant in the case of the isovectormore » scalar (a{sub 0}) correlator. Specifically, once the parameters m{sub res}, {delta}{sub mix}, and two others that can be determined from the light pseudoscalar meson spectrum are known, the two-particle intermediate state 'bubble' contribution to the scalar correlator is completely predicted within MA{chi}PT. We find that the behavior of the scalar meson correlator is quantitatively consistent with the MA{chi}PT prediction; this supports the claim that MA{chi}PT describes the dominant unitarity-violating effects in the mixed-action theory and can therefore be used to remove lattice artifacts and recover physical quantities.« less
96483107
Symanzik flow on HISQ ensembles
=a, originally proposed bythe BMW collaboration, is computed using Symanzik ﬂow at four lattice spacings ranging from0.15 to 0.06 fm. With a Taylor series ansatz, the results are simultaneously extrapolated to thecontinuum and interpolated to physical quark masses. We give a preliminary determination of thescale w
118573725
Lessons for new physics from CKM studies
We perform a global fit to the CKM unitarity triangle using the latest experimental and theoretical constraints. We present results for three different sets of constraints: the standard inputs used by CKMfitter and UTFit, the standard inputs minus |Vub|, and the standard inputs minus both |Vub| and |Vcb|. For the required nonperturbative weak matrix elements, we use three-flavor lattice QCD averages from www.latticeaverages.org; these have been updated to reflect all available lattice calculations as of the "End of 2010". Given current theoretical and experimental inputs, we observe an approximately 3{\sigma} tension in the CKM unitarity triangle that can be interpreted as sign of physics beyond the standard model in the flavor sector. Using a model-independent parameterization of new physics effects, we test the compatibility of new physics in kaon mixing, in B-mixing, or in B \rightarrow {\tau} {\nu} decay with the current data. Although the tension could be accommodated with each hypothesis, the scenarios with new physics in B-mixing or, to a lesser extent, in B \rightarrow {\tau} {\nu} decay are strongly preferred. Finally, we interpret these results in terms contributions to \Delta S = 2 and \Delta B = 2 four-fermion operators. We find that the preferred scale of new physics (with Standard Model like couplings) is in the few hundred GeV range.