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We search for CP violation in a sample of 20,000 Cabibbo-suppressed decays, $D^+\rightarrow K^+K^0_S\pi^+\pi^-$, and 30,000 Cabibbo-favored decays, $D_s^+\rightarrow K^+K^0_S\pi^+\pi^-$. We use 520 $fb^{-1}$ of data recorded by the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ collider operating at center of mass energies near 10.6 $GeV$. We search for CP violation in the difference between the $T$-odd asymmetries obtained using triple product correlations of the $D^+$ ($D_s^+$) and $D^-$ ($D_s^-$) decays, respectively. The $T$ violation parameter values obtained are $\mathcal{A}_T(D^+) = (-12.0 \pm 10.0_{stat} \pm 4.6_{syst})\times 10^{-3}$ and $\mathcal{A}_T(D_s^+) = (-13.6 \pm 7.7_{stat} \pm 3.4_{syst}) \times10^{-3}$, which are consistent with the Standard Model expectations.
We present a study of the decays B^{+-} --> D K^{+-} with D mesons reconstructed in the K+pi-pi0 or K-pi+pi0 final states, where D indicates a D0 or a anti-D0 meson. Using a sample of 474 million BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC we obtain R^{+} = (5^{+12}_{-10}(stat) ^{+2}_{-4}(syst))\times10^{-3} and R^{-} = (12^{+12}_{-10}(stat) ^{+3}_{-5}(syst))\times10^{-3}, from which we extract the upper limits at 90% probability: R^+<23\times10^{-3} and R^-<29\times10^{-3}. Using these measurements, we obtain an upper limit for the ratio rB of the magnitudes of the b --> u and b --> c amplitudes r_B<0.13 at 90% probability.
We analyze the decay B0-->K+ pi- pi0 with a sample of 454 million B Bbar events collected by the BaBar detector at the PEP-II asymmetric-energy B factory at SLAC, and extract the complex amplitudes of seven interfering resonances over the Dalitz plot. These results are combined with amplitudes measured in B0-->K_S pi+ pi- decays to construct isospin amplitudes from B0-->K* pi and B0-->rho K decays. We measure the phase of the isospin amplitude Phi_3/2, useful in constraining the CKM unitarity triangle angle gamma and evaluate a CP rate asymmetry sum rule sensitive to the presence of new physics operators. We measure direct CP violation in B0-->K*+ pi- decays at the level of 3 sigma when measurements from both B0-->K+ pi- pi0 and B0-->K_S pi+ pi- decays are combined.
The decay width and mass of the Ds1(2536)+ meson are measured via the decay channel Ds1+ -> D*+KS0 using 385 fb^-1 of data recorded with the BABAR detector in the vicinity of the Y(4S) resonance at the PEP-II asymmetric-energy electron-positron collider. The result for the decay width is 0.92 +- 0.03 (stat) +- 0.04 (syst) MeV. For the mass, a value of 2535.08 +- 0.01 +- 0.15 MeV/c^2 is obtained. The mass difference between the Ds1+ and the D*+ is measured to be 524.83 +- 0.01 +- 0.04 MeV/c^2, representing a significant improvement compared to the current world average. The unnatural spin-parity assignment for the Ds1+ meson is confirmed.
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.
Comment: 8 pages, 4 postscript figures, submitted to Phys. Rev. D (Rapid Communications)
Comment: 19 pages, 8 figures, published by Phys. Rev. D
Comment: 7 pages, 7 figures, submitted to Phys. Rev. D (Rapid Communications)
Comment: 7 pages, 5 postscript figures, submitted to Physical Review Letters
We study the process e+e- -> pi+pi-pi+pi-gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb^-1 of data collected with the BABAR detector at SLAC, corresponding to approximately 260,000 signal events. We use these data to extract the non-radiative sigma(e+e- ->pi+pi-pi+pi-) cross section in the energy range from 0.6 to 4.5 Gev. The total uncertainty of the cross section measurement in the peak region is less than 3%, higher in precision than the corresponding results obtained from energy scan data.
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