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# Search results

32 records were found.

## A New Technique for the Direct Measurement of the Electron Anti-Neutrino Mass

Comment: Paper withdrawn because of unjustified approiximation between equations 13 and 14

## Studies of Electron Avalanche Behavior in Liquid Argon

Comment: 7 pages, 8 figures

## Status of the DIRC Detector at Babar : Early Operational Experience

A novel type of Cherenkov ring imaging particle identification system (DIRC) based on the detection of ring images produced in long, fused silica radiator bars is being used to provide hadronic particle identification in the BABAR detector at PEP-II. The DIRC concept, design, fabrication, and initial performance will be briefly described. The DIRC is now fully commissioned, and has been operating in the BABAR detector on beam line at the PEP-II B Factory since late Spring 1999.

## Measurement of Time-Dependent CP Asymmetries and Constraints on sin$(2\beta+\gamma)$ with Partial Reconstruction of $B^0 \to D^{*\mp} \pi^{\pm}$ Decays

We present a preliminary measurement of the time-dependent CP-violating asymmetry in decays of neutral B mesons to the final states D*-+ pi+- using approximately 178 million BB events recorded by the BaBar experiment at the PEP-II e+e- storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum pi+- from the B decay and the low-momentum pi-+ from the D*-+ decay are used. % We measure the amplitude of the asymmetry to be $-0.041 \pm 0.016 (stat.) \pm 0.010 (syst.)$ and determine bounds on $|\sin(2 \beta + \gamma)|$.

## Measurement of CP-Violating Asymmetries in $B^0\to(\rho \pi)^0$ Using a Time-Dependent Dalitz Plot Analysis

We present the preliminary measurement of CP-violating asymmetries in B0->(rhopi)0->pi+pi-pi0 decays using a time-dependent Dalitz plot analysis. The results are obtained from a data sample of 213 million Y(4S)->BB-bar decays, collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. This analysis extends the narrow-rho quasi-two-body approximation used in the previous analysis, by taking into account the interference between the rho resonances of the three charges. We measure 16 coefficients of the bilinear form factor terms occurring in the time-dependent decay rate of the B0 meson with the use of a maximum-likelihood fit. We derive the physically relevant quantities from these coefficients. We measure the direct CP-violation parameters Acp = -0.088 +- 0.049 +- 0.013 and C = 0.34 +- 0.11 +- 0.05, where the fi...

## Measurement of the Branching Fractions for the Exclusive Decays of $B^0$ and $B^+ \to \bar{D}^{*}D^{*}K$

We report the observation of 823+/-57 B^0 and 970+/-65 B^+ decays to doubly charmed final states Dbar^(*)D^(*)K, where Dbar^(*) and D^(*) are fully reconstructed and K is either a K+/- or a K^0. We use a sample of 82.3+/- 0.9 million BBbar events collected between 1999 and 2002 with the babar detector at the PEP-II storage ring at the Stanford Linear Accelerator Center. The 22 possible B decays to Dbar^(*)D^(*)K are reconstructed exclusively and the corresponding branching fractions or limits are determined. The branching fractions of the B^0 and of the B^+ to Dbar^(*)D^(*)K$are found to be BR(B^0 --> Dbar^(*) D^(*) K) = (4.3 +/- 0.3 stat +/- 0.6 syst)%, BR(B^+ --> Dbar^(*) D^(*) K) = (3.5 +/- 0.3 stat +/- 0.5 syst)%. A search for decays to orbitally excited$D_s\$ states, B --> Dbar^(*) D_{sJ}^{+} (D_{sJ}^{+} --> D^(*)0K^+) is also pe...