Asymmetric brønsted Acid catalysis enabling hydroaminations of dienes and allenes

Acid treatment: Toste et?al. recently unveiled a new pathway for asymmetric Br?nsted acid catalysis of reactions involving dienes or allenes, and achieved highly efficient intramolecular hydroamination and hydroarylation reactions. The P?S bond proved necessary for reactivity, and dithiophosphoric acids emerged as efficient catalysts. The association/displacement sequence led to chiral pyrrolidines and isoxazolidines in excellent yields and ee?values.     

Linear Conforming and Nonconforming Upwind Finite Elements for the Convection-Diffusion Equation

A conforming and a nonconforming method for the approximationof the stationary 2-D convection-diffusion equation at highP?clet number are presented. Convergence of order h is provedin a generic case and, for a particular choice of the upwindschemes, a discrete maximum principle is established under veryunrestrictive conditions on the mesh. Results of numerical computationsare produced to show the practical convergence of these methods.     

Measurement of ΔσL in pp scattering between 200 and 583 MeV

The main structure around m = 2.15 GeV first observed by the Argonne group in the spin-dependent total cross section Δσ_L is confirmed in the energy range available at SIN. A simultaneous study of the scattered particles at small angles has been carried out with success and gave the spin-correlation parameter A_00kk for the pp elastic scattering and for the reaction pp → π⁺d. The contribution of the 3-body reactions to this spin-dependent total cross section has been deduced and found to be lower than the contribution of the π⁺d reaction even at 583 MeV.     

Pressure viscosity behavior of various fluids

Abstract

Many works have been published on the pressure viscosity dependence of liquids. The difficulty to fit experimental results with a simple and universal law has been often put in evidence. According to our experimental results, we show that a power law is an acceptable alternative to the common Barus law.     

Search for doubly charged Higgs bosons with lepton-flavor-violating decays involving tau leptons

We search for pair production of doubly charged Higgs particles (H+/- +/-) followed by decays into electron-tau (etau) and muon-tau (mutau) pairs using data (350 pb(-1) collected from [over]pp collisions at sqrt[s]=1.96 TeV by the CDF II experiment. We search separately for cases where three or four final-state leptons are detected, and combine results for exclusive decays to left-handed etau (mutau) pairs. We set an H+/- +/- lower mass limit of 114(112) GeV/c(2) at the 95% confidence level.     

Search for Bs0 --> micro+ micro- and B0 --> micro+ micro- decays with 2 fb-1 of pp collisions

We have performed a search for B(s)(0) --> micro(+) micro(-) and B(0) --> micro(+) micro(-) decays in pp collisions at square root s = 1.96 TeV using 2 fb(-1) of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron Collider. The observed number of B(s)(0) and B0 candidates is consistent with background expectations. The resulting upper limits on the branching fractions are B(B(s)0) --> micro(+) micro(-)) <5.8 x 10(-8) and B(B(0) --> micro(+) micro(-))<1.8 x 10(-8) at 95% C.L.     

First observation of the decay Bs0-->Ds-Ds+ and measurement of its branching ratio

We report the observation of the exclusive decay Bs0-->Ds-Ds+ at the 7.5 standard deviation level using 355 pb(-1) of data collected by the CDF II detector in pp collisions at sqrt[s]=1.96 TeV at the Fermilab Tevatron. We measure the relative branching ratio B(Bs0-->Ds-Ds+)/B(B0-->D-Ds+)=1.44(-0.44)(+0.48). Using the world average value for B(B0-->D-Ds+), we find B(Bs0-->Ds-Ds+)=(9.4(-4.2)(+4.4))x10(-3). This provides a lower bound DeltaGammasCP/Gammas>or=2B(Bs0-->Ds-Ds+)>1.2x10(-2) at 95% C.L.     

Search for heavy toplike quarks using lepton plus jets events in 1.96 TeV pp collisions

We present the results of a search for pair production of a new heavy toplike quark t' decaying to a W boson and another quark using the Collider Detector at Fermilab II detector in run II of the Tevatron pp collider. Using a data sample corresponding to 760 pb(-1) of integrated luminosity, we fit the observed spectrum of total transverse energy and reconstructed t' quark mass to a combination of standard model processes and t' pair production. We see no evidence for t't' production, and we infer a lower limit of 256 GeV/c(2) on the mass of the t' at 95% C.L. assuming standard strong couplings for the t'.