arXiv subjects
Publications and source records attributed to Y. Sakai.
The proper-time resolution function for the measurement of the time evolution of B mesons with the Belle detector at KEKB is studied in detail. The obtained resolution function is applied to the measurement of B meson lifetimes, the B0-B0bar oscillation frequency and time-dependent CP asymmetries.
This report presents the results of studies that investigate the physics reach at a Super B factory, an asymmetric-energy e^+e^- collider with a design luminosity of 5 x 10^35 cm^-2s^-1, which is around 40 times as large as the peak luminosity achieved by the KEKB collider. The studies focus on flavor physics and CP violation measurements that could be carried out in the LHC era. The physics motivation, key observables, measurement methods and expected precisions are presented. The sensitivity studies are a part of the activities associated with the preparation of a Letter of Intent for SuperKEKB, which has been submitted recently.
We describe a flavor tagging algorithm used in measurements of the CP violation parameter sin2phi_1 at the Belle experiment. Efficiencies and wrong tag fractions are evaluated using flavor-specific B meson decays into hadronic and semileptonic modes. We achieve a total effective efficiency of $ 28.8 +- 0.6 %.
We report results of proper-time evolution analyses of B decays at Belle, based on a 29.1/fb data sample recorded at the Upsilon (4S) resonance. These results include measurements of sin2phi_1, the lifetime of B-mesons, and the mass-difference between two mass eigenstates of the B^0-B^0-bar system (Delta-m_d). Delta-m_d is measured using three different methods: fully reconstructed hadronic modes, a fully reconstructed semi-leptonic mode, and a partially reconstructed D*+ pi- mode.