Trapping in irradiated p-on-n silicon sensors at fluences anticipated at the HL-LHC outer tracker

The degradation of signal in silicon sensors is studied under conditions expected at the CERN High-Luminosity LHC. 200 $\mu$m thick n-type silicon sensors are irradiated with protons of different energies to fluences of up to $3 \cdot 10^{15}$ neq/cm$^2$. Pulsed red laser light with a wavelength of 672 nm is used to generate electron-hole pairs in the sensors. The induced signals are used to determine the charge collection efficiencies separately for electrons and holes drifting through the sensor. The effective trapping rates are extracted by comparing the results to simulation. The electric field is simulated using Synopsys device simulation assuming two effective defects. The generation and drift of charge carriers are simulated in an independent simulation based on PixelAV. The effective trapping rates are determined from the measured charge collection efficiencies and the simulated and measured time-resolved current pulses are compared. The effective trapping rates determined for both electrons and holes are about 50% smaller than those obtained using standard extrapolations of studies at low fluences and suggests an improved tracker performance over initial expectations

Measurement of the branching fraction and CP violating asymmetries in neutral B decays to D*+- D-+

We present measurements of the branching fraction and CP-violating asymmetries for neutral B decays to D*+-D-+. The measurement uses a data sample of approximately 88 million Y(4S) --> B Bbar decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. We measure the branching fraction to be (8.8 +- 1.0 +- 1.3) x 10^-4 and the time-integrated CP-violating asymmetry between the rates to D*+D- and D*-D+ to be A = -0.03 +- 0.11 +- 0.05. We also measure the time-dependent CP-violating asymmetry parameters to be S-+ = -0.24 +- 0.69 +- 0.12, C-+ = -0.22 +- 0.37 +- 0.10 for B --> D*-D+ and S+- = -0.82 +- 0.75 +- 0.14$, C+- = -0.47 +- 0.40 +- 0.12 for B --> D*+D-. In each case the first error is statistical and the second error is systematic.Comment: 7 pages, 3 figures, published as Phys. Rev. Lett 90 (2003) 22180

Measurement of the branching fraction for inclusive semileptonic B meson decays

A largely model-independent measurement of the inclusive electron momentum spectrum and branching fraction for semileptonic decays of B mesons is presented based on data recorded at the Upsilon(4S) resonance with the BABAR detector. Backgrounds from secondary charm decays are separated from prompt B decays using charge and angular correlations between the electron from one B meson and a high momentum electron tag from the second B meson. The resulting branching fraction is BR(B -> X e nu) = (10.87 +-0.18(stat)+-0.30(syst))%. Based on this measurement we determine the CKM matrix element |V_cb|

Measurement of the branching fraction for inclusive semileptonic B meson decays

A largely model-independent measurement of the inclusive electron momentum spectrum and branching fraction for semileptonic decays of B mesons is presented based on data recorded at the Upsilon(4S) resonance with the BABAR detector. Backgrounds from secondary charm decays are separated from prompt B decays using charge and angular correlations between the electron from one B meson and a high momentum electron tag from the second B meson. The resulting branching fraction is BR(B -> X e nu) = (10.87 +-0.18(stat)+-0.30(syst))%. Based on this measurement we determine the CKM matrix element |V_cb|

SuperB: A High-Luminosity Asymmetric e+ e- Super Flavor Factory. Conceptual Design Report.

The physics objectives of SuperB, an asymmetric electron-positron collider with a luminosity above 10^36/cm^2/s are described, together with the conceptual design of a novel low emittance design that achieves this performance with wallplug power comparable to that of the current B Factories, and an upgraded detector capable of doing the physics in the SuperB environment

Measurement of B0 ---> D(*)+ D*- branching fractions and B0 ---> D*+(s) D*- polarization with a partial reconstruction technique

We present a study of the decays B0->D_s(*)+D*-, using 20.8 fb-1 of e+e- annihilation data recorded with the BABAR detector. The analysis is conducted with a partial reconstruction technique, in which only the D_s(*)+ and the soft pion from the D*- decay are reconstructed. We measure the branching fractions BR(B0->D_s+D*-) = (1.03 +/- 0.14 +/- 0.13 +/- 0.26)% and BR(B0->D_s*+D*-) = (1.97 +/- 0.15 +/- 0.30 +/- 0.49)%, where the first error is statistical, the second is systematic, and the third is the error due to the D_s+->phi pi+ branching fraction uncertainty. From the B0->D_s*+D*- angular distributions, we measure the fraction of longitudinal polarization Gamma_L/Gamma = (51.9 +/- 5.0 +/- 2.8)%, which is consistent with theoretical predictions based on factorization.Comment: 9 pages, 4 postscript figues, submitted to Physical Review D (Rapid Communications