69 research outputs found

    Measurement of the CP Violation Parameters in B0 -> pi+ pi- Decays

    Full text link
    We present a measurement of the time-dependent charge-parity (CP) violation parameters in B0 -> pi+ pi- decays. The results are obtained from the final data sample containing 772 million BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain the CP violation parameters Acp = +0.33 +/- 0.06 (stat) +/- 0.03 (syst) and Scp = -0.64 +/- 0.08 (stat) +/- 0.03 (syst), where Acp and Scp represent the direct and mixing-induced CP asymmetry, respectively. Using an isospin analysis including results from other Belle measurements, we find 23.8 < phi2 < 66.8 degrees is disfavored at the 1 sigma level, where phi2 is one of the three interior angles of the CKM unitarity triangle related to B_{u,d} decays.Comment: 16 pages, 5 figures, CKM2012 conference paper, Submitted to PR

    Angular analysis of B0→K∗(892)0ℓ+ℓ−B^0 \to K^\ast(892)^0 \ell^+ \ell^-

    Full text link
    We present a measurement of angular observables, P4â€ČP_4', P5â€ČP_5', P6â€ČP_6', P8â€ČP_8', in the decay B0→K∗(892)0ℓ+ℓ−B^0 \to K^\ast(892)^0 \ell^+ \ell^-, where ℓ+ℓ−\ell^+\ell^- is either e+e−e^+e^- or ÎŒ+Ό−\mu^+\mu^-. The analysis is performed on a data sample corresponding to an integrated luminosity of 711 fb−1711~\mathrm{fb}^{-1} containing 772×106772\times 10^{6} BBˉB\bar B pairs, collected at the ΄(4S)\Upsilon(4S) resonance with the Belle detector at the asymmetric-energy e+e−e^+e^- collider KEKB. Four angular observables, P4,5,6,8â€ČP_{4,5,6,8}' are extracted in five bins of the invariant mass squared of the lepton system, q2q^2. We compare our results for P4,5,6,8â€ČP_{4,5,6,8}' with Standard Model predictions including the q2q^2 region in which the LHCb collaboration reported the so-called P5â€ČP_5' anomaly.Comment: Conference paper for LHC Ski 2016. SM prediction for P6â€ČP_{6}' corrected and reference for arXiv:1207.2753 adde

    Belle II Technical Design Report

    Full text link
    The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un

    The Physics of the B Factories

    Get PDF
    This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C
    • 

    corecore