Studies in metal sulphite chemistry—III

Manganese(II) iodide, iron(II) iodide and copper(I) iodide each react with tetramethylammonium disulphite to form anhydrous manganese(II) sulphite, iron(II) sulphite and copper(I) disulphite respectively. Iron(II) sulphite and copper(I) disulphite react with dimethylsulphoxide-sulphur dioxide to form iron(II) disulphate and copper(II) disulphate respectively. Hydrated sulphites of manganese(II), iron(II), magnesium(II) and calcium(II) were also prepared. The properties of the sulphites were investigated using thermogravimetric and IR measurements.     

SAXS determination of the amorphous surface layer thickness of polymer single crystals

Polyethylene single crystals were grown from 0.1% solutions in xylene at 80 and 87°C. Oriented mats were made from each preparation and the small-angle x-ray scattering (SAXS) profiles obtained. Following treatment of the raw data for main-beam position and width, background scatter, and the Lorentz factor, five Bragg reflections were resolved. A one-dimensional lattice was used as a model for the oriented mats of single crystals. This model contains three parameters. An additional parameter G_x was also introduced to demonstrate the general effect of a broadening factor on the model. The effect of each parameter on the calculated diffraction pattern was examined. From this examination it was found that by assuming that the broadening functions are zero we can determine directly from the number of observable peaks the maximum possible thickness of the amorphous surface. Further, we find that the thickness of the amorphous layer must be less than the maximum value calculated if G_x is assigned values greater than zero. A “best-fit” diffraction pattern was generated in order to estimate how much smaller the surface thickness can be such that one can still resolve five diffraction maxima. The range of amorphous surface thicknesses found from the calculated diffraction profile is 12–20 Å. This is in good agreement with complementary studies performed on the same crystal preparations.     

Improved Measurement of the Cabibbo-Kobayashi-Maskawa angle alpha using B0(B) --> rho+rho- decays

We present results from an analysis of B(0)B(0)--> rho(+)rho(-) using 232 x 10(6) Gamma (4S) --> BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We measure the longitudinal polarization fraction f(L) = 0.978 +/- 0.014(stat) + 0.021 / -0.029(syst) and the CP-violating parameters S(L)= -0.33 +/- 0.24(stat) + 0.08 / -0.14(syst) and C(L)= -0.03 +/- 0.18(stat) +/- 0.09(syst). Using an isospin analysis of B --> rhorho decays, we determine the unitarity triangle parameter alpha. The solution compatible with the standard model is alpha = (100 +/- 13) degrees.     

Measurement of the branching fraction of Gamma(4S) --> B0B0

We report the first measurement of the branching fraction f(00) for Gamma(4S) --> B(0)B(0). The data sample consists of 81.7 fb(-1) collected at the Gamma(4S) resonance with the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring. Using partial reconstruction of the decay B(0) --> D(*+) l(-)nu(l) in which only the charged lepton and the soft pion from the decay D(*+) --> D(0)pi(+) are reconstructed, we obtain f(00) = 0.487 +/- 0.010(stat) +/- 0.008(syst). Our result does not depend on the branching fractions of B(0) --> D(*+)l(-)nu(l) and D(*+) --> D(0)pi(+) decays, on the ratio of the charged and neutral B meson lifetimes, nor on the assumption of isospin symmetry.     

Search for the rare leptonic decay B--->tau-nutau

We present a search for the decay B(-)--> tau(-)nu(tau) in a sample of 88.9 x 10(6) BB pairs recorded with the BABAR detector at the Stanford Linear Accelerator Center B factory. One of the two B mesons from the Gamma(4S) is reconstructed in a hadronic or a semileptonic final state, and the decay products of the other B in the event are analyzed for consistency with a B(-) --> tau(-)nu(tau) decay. We find no evidence of a signal and set an upper limit on the branching fraction of B(B(-) --> tau(-) nu(tau)) < 4.2 x 10(-4) at the 90% confidence level.     

Search for lepton flavor violation in the decay tau+/- --> mu+ gamma

A search for the nonconservation of lepton flavor number in the decay tau(+/-) --> mu(+/-) has been performed using 2.07 x 10(8) e(+ )e(-) tau(+) tau(-) events produced at a center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage ring. We find no evidence for a signal and set an upper limit on the branching ratio of Beta(tau(+/-) --> mu(+/-) gamma) < 6.8 x 10(-8) at 90% confidence level.     

Limit on the B0-->rho0rho0 branching fraction and implications for the Cabibbo-Kobayashi-Maskawa angle alpha

We search for the decay B0-->rho(0)rho(0) in a data sample of about 227x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We find no significant signal and set an upper limit of 1.1x10(-6) at 90% C.L. on the branching fraction. As a result, the uncertainty due to penguin contributions on the Cabibbo-Kobayashi-Maskawa unitarity angle alpha measured in B-->rhorho decays is decreased to 11 degrees at 68% C.L.     

Measurements of the branching fraction and CP-violation asymmetries in B0-->f0(980)K0S

We present measurements of the branching fraction and CP-violating asymmetries in the decay B0-->f0(980)K0S. The results are obtained from a data sample of 123 x 10(6) Upsilon(4S)-->BB decays. From a time-dependent maximum likelihood fit, we measure the branching fraction B(B0-->f0(980)(-->pi+pi-)K0)=(6.0+/-0.9+/-0.6+/-1.2)x10(-6), the mixing-induced CP violation parameter S=-1.62(+0.56)(-0.51)+/-0.09+/-0.04, and the direct CP violation parameter C=0.27+/-0.36+/-0.10+/-0.07, where the first errors are statistical, the second systematic, and the third due to model uncertainties. We measure the f0(980) mass and width to be mf0(980)=(980.6+/-4.1+/-0.5+/-4.0) MeV/c2 and Gammaf0(980)=(43(+12)(-9)+/-3+/-9) MeV/c2, respectively.     

Study of high momentum eta' production in B --> eta'Xs

We measure the branching fraction for the charmless semi-inclusive process B --> eta'Xs, where the eta' meson has a momentum in the range 2.0 to 2.7 GeV/c in the upsilon4S center-of-mass frame and Xs represents a system comprising a kaon and zero to four pions. We find B(B --> eta'Xs) = [3.9 +/- 0.8(stat) +/- 0.5(syst) +/- 0.8(model)] x 10(-4). We also obtain the Xs mass spectrum and find that it fits models predicting high masses.