arXiv subjects

Y. Ushiroda

Publications and source records attributed to Y. Ushiroda.

5 recordsLinked to original sources

arXiv2010

Physics at Super B Factory

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 $8 \times 10^{35}$ cm$^{-2}$s$^{-1}$, which is around 50 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.

hep-ex↗

arXiv2008

sBelle Design Study Report

In this note, we compile results of various simulation studies for the upgrade of the Belle detector. Based on these studies, we propose a set of optimum or appropriate parameters of the detector.

hep-ex↗

arXiv2008

Time-Dependent {\boldmath $CP$}-Violating Asymmetry in $B^0\toρ^0γ$ Decays

We report the first measurement of CP-violation parameters in $B^0\toρ^0γ$ decays based on a data sample of $657\times 10^6 B\bar{B}$ pairs collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The flavor of the $B$ meson is identified from the decay products of the accompanying $B$ meson. We obtain the time-dependent and direct CP-violating parameters, $\cals_{\rhozγ} = -0.83\pm 0.65(stat)\pm 0.18(syst)$ and $\cala_{\rhozγ} = -0.44\pm 0.49(stat)\pm 0.14(syst)$, respectively.

hep-ex↗

arXiv2006

Time-Dependent CP Asymmetries in B0 -> Ks pi0 gamma transitions

We report measurements of CP violation parameters in B0->Ks pi0 gamma transitions based on a data sample of 535x10^6 BB pairs collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. One neutral B meson is fully reconstructed in the B0->Ks pi0 gamma mode. The flavor of the accompanying B meson is identified from its decay products. For a Ks pi0 invariant mass up to 1.8 GeV/c^2, we obtain S = -0.10 +- 0.31 +- 0.07 and A = -0.20 +- 0.20 +- 0.06. For a Ks pi0 invariant mass near the K*0(892) resonance, we obtain S = -0.32 +0.36-0.33 +-0.05 and A=-0.20 +-0.24 +-0.05.

hep-ex↗

arXiv2005

Measurement of Time-Dependent CP-Violating Asymmetry in B0 -> Ks pi0 gamma Decay

We present a new measurement of CP-violation parameters in B0 -> Ks pi0 gamma decay based on a sample of 275 x 10^6 B\bar{B} pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e^+e^- collider. One of the B mesons is fully reconstructed in the B0 -> Ks pi0 gamma decay. The flavor of the accompanying B meson is identified from its decay products. CP-violation parameters are obtained from the asymmetry in the distribution of the proper-time intervals between the two B decays. We obtain S_Kspi0gamma = -0.58 +0.46-0.38(stat) +-0.11(syst) and A_Kspi0gamma = +0.03 +-0.34(stat) +-0.11(syst), for the Kspi0 invariant mass covering the full range up to 1.8 GeV/c^2. We also measure the CP-violation parameters for the case B0 -> K*0(-> Kspi0) gamma and obtain S_K*0gamma = -0.79 +0.63-0.50(stat) +- 0.10(syst) for A_K*0gamma fixed at 0.

hep-ex↗