A search for charmed baryons decaying to $D^0 p$ reveals two states: the $\Lambda_c(2880)^+$ baryon and a previously unobserved state at a mass of $2939.8\pm 1.3 \text{(stat.)}\pm 1.0 ...\text{(syst.)}$~\mevcc and with an intrinsic width of $17.5\pm 5.2 \text{(stat.)}\pm 5.9 \text{(syst.)}$~\mev. Consistent and significant signals are observed for the $K^-\pi^+$ and $K^-\pi^+\pi^-\pi^+$ decay modes of the $D^0$ in 287 ${\rm fb}^{-1}$ annihilation data recorded by the BaBar detector at a center-of-mass energy of 10.58~${\rm GeV}/c^2$. There is no evidence in the $D^+ p$ spectrum of doubly-charged partners. The mass and intrinsic width of the $\Lambda_c(2880)^+$ baryon and relative yield of the two baryons are also measured.
We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional ...sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2 beta, is derived from the decay time distributions in such events. The result sin2 beta = 0.59+/-0.14(stat)+/-0.05(syst) establishes CP violation in the B(0) meson system. We also determine absolute value of lambda = 0.93+/-0.09(stat)+/-0.03(syst), consistent with no direct CP violation.
We present measurements of the decays B+ -> X(3872) K+ and B0 -> X(3872) K0 with X(3872) -> Jpsi pi+ pi-. The data sample used, collected with the BABAR detector at the PEP-II e+e- asymmetric-energy ...storage ring, corresponds to 455 x 10^6 BBbar pairs. Branching fraction measurements of BF(B+ -> X(3872) K+) x BF(X(3872) -> Jpsi pi+ pi-) = (8.4 +/- 1.5 +/- 0.7) x 10^{-6} and BF(B0 -> X(3872) K0) x BF(X(3872) -> Jpsi pi+ pi- = (3.5 +/- 1.9 +/- 0.4) x 10^{-6} are obtained. We set an upper limit on the natural width of the X(3872) of Gamma < 3.3 MeV/c^2 at the 90% confidence level.
The DIRC particle identification system for the BaBar experiment Aleksan, R.; Amerman, L.; Aston, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2005, Volume:
538, Issue:
1-3
Journal Article
Peer reviewed
Open access
A new type of ring-imaging Cherenkov detector is being used for hadronic particle identification in the BABAR experiment at the SLAC B Factory (PEP-II). This detector is called DIRC, an acronym for ...Detection of Internally Reflected Cherenkov (Light). This paper will discuss the construction, operation and performance of the BABAR DIRC in detail.
Using a data sample corresponding to an integrated luminosity of 342 fb − 1 collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a center-of-mass ...energy near 10.58 GeV, we measure B ( τ − → π − π − π + ν τ ( ex . K 0 S ) ) = ( 8.83 ± 0.01 ± 0.13 ) % , B ( τ − → K − π − π + ν τ ( ex . K 0 S ) ) = ( 0.273 ± 0.002 ± 0.009 ) % , B ( τ − → K − π − K + ν τ ) = ( 0.1346 ± 0.0010 ± 0.0036 ) % , and B ( τ − → K − K − K + ν τ ) = ( 1.58 ± 0.13 ± 0.12 ) × 10 − 5 , where the uncertainties are statistical and systematic, respectively. These include significant improvements over previous measurements and a first measurement of B ( τ − → K − K − K + ν τ ) in which no resonance structure is assumed. We also report a first measurement of B ( τ − → ϕ π − ν τ ) = ( 3.42 ± 0.55 ± 0.25 ) × 10 − 5 , a new measurement of B ( τ − → ϕ K − ν τ ) = ( 3.39 ± 0.20 ± 0.28 ) × 10 − 5 and a first upper limit on B ( τ − → K − K − K + ν τ ( ex . ϕ ) ) .
Measurement of electron drift parameters for helium and CF4-based gases
Nuclear instruments and methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment/Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment
Journal Article
We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K ± π ∓ π ± . Using a sample of ( 383.2 ± 4.2 ) × 10 6 B ¯¯¯ B pairs collected by the BABAR ...detector, we measure C P -averaged branching fractions and direct C P asymmetries for intermediate resonant and nonresonant contributions. We find evidence for direct C P violation in the decay B ± → ρ 0 ( 770 ) K ± , with a C P -violation parameter A C P = ( + 44 ± 10 ± 4 + 5 − 13 ) % .
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