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H. Ishino

Publications and source records attributed to H. Ishino.

45 records · Page 3Linked to original sources
arXiv2011

Letter of Intent: The Hyper-Kamiokande Experiment --- Detector Design and Physics Potential ---

We propose the Hyper-Kamiokande (Hyper-K) detector as a next generation underground water Cherenkov detector. It will serve as a far detector of a long baseline neutrino oscillation experiment envisioned for the upgraded J-PARC, and as a detector capable of observing -- far beyond the sensitivity of the Super-Kamiokande (Super-K) detector -- proton decays, atmospheric neutrinos, and neutrinos from astronomical origins. The baseline design of Hyper-K is based on the highly successful Super-K, taking full advantage of a well-proven technology. (to be continued)

hep-ex↗
arXiv2010

Atmospheric neutrino oscillation analysis with sub-leading effects in Super-Kamiokande I, II, and III

We present a search for non-zero theta_{13} and deviations of sin^2 theta_{23} from 0.5 in the oscillations of atmospheric neutrino data from Super-Kamiokande -I, -II, and -III. No distortions of the neutrino flux consistent with non-zero theta_{13} are found and both neutrino mass hierarchy hypotheses are in agreement with the data. The data are best fit at Delta m^2 = 2.1 x 10^-3 eV^2, sin^2 theta_{13} = 0.0, and sin^2 theta_{23} =0.5. In the normal (inverted) hierarchy theta_{13} and Delta m^2 are constrained at the one-dimensional 90% C.L. to sin^2 theta_{13} < 0.04 (0.09) and 1.9 (1.7) x 10^-3 < Delta m^2 < 2.6 (2.7) x 10^-3 eV^2. The atmospheric mixing angle is within 0.407 <= sin^2 theta_{23} <= 0.583 at 90% C.L.

hep-ex↗
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.

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arXiv2007

Measurement of CP Asymmetry in a Time-Dependent Dalitz Analysis of B^0 \to (ρπ)^0 and a Constraint on the Quark Mixing Matrix Angle ϕ_2

We present a measurement of CP asymmetry using a time-dependent Dalitz plot analysis of B0 --> pi+pi-pi0 decays based on a 414/fb data sample containing 449M BB pairs. The data was collected on the $Υ$(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. Combining our analysis with information on charged B decay modes, we perform a full Dalitz and isospin analysis and obtain a constraint on the CKM angle $ϕ_2$, 68 deg. < $ϕ_2$ < 95 deg. as the 68.3% confidence interval for the $ϕ_2$ solution consistent with the standard model (SM). A large SM-disfavored region also remains.

hep-ex↗
arXiv2007

Observation of Direct CP-Violation in B0 --> pi+pi- Decays and Model-Independent Constraints on phi2

We present a new measurement of the time-dependent CP-violating parameters in B0 -> pi+pi- decays using a data sample that contains 535M BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider operating at the Upsilon(4S) resonance. We reconstruct one neutral B meson as a pi+pi- CP eigenstate and identify the flavor of the accompanying B meson from its decay products. We find 1464+-65 B0 --> pi+pi- events and perform an unbinned maximum likelihood fit to the distribution of the proper-time differences between the two B meson decays. The fit yields the CP-violating parameters: Spipi = -0.61 +- 0.10(stat) +- 0.04(syst) and Apipi = +0.55 +- 0.08(stat) +- 0.05(syst). Large direct CP-violation is observed with a significance greater than 5 standard deviations for any Spipi value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle phi2 = (97 +- 11) degrees for the solution consistent with the standard model and exclude a range of 11<phi2<79 degrees at the 95% confidence level.

hep-ex↗
arXiv2007

New Measurements Using External Photon Conversion at a High Luminosity B Factory

We propose two novel methods for testing the standard model using external photon conversion at a high-luminosity e^+e^- B factory proposed recently. The first method is to measure the mixing-induced CP-violation parameter S_{pi^0pi^0} in B^0 --> pi^0 pi^0 decays. The precision of S_{pi^0pi^0} is estimated to be 0.23 from a Monte Carlo study for a data sample containing 50 x 10^9 BBbar pairs. We demonstrate that this measurement is crucial for reducing the discrete ambiguity of the Cabibbo-Kobayashi-Maskawa angle phi_2 determined from the isospin analysis with B --> pi pi decays. The second method is to measure photon polarization in B^0 --> K^{*0}(--> K^+ pi^-) gamma decays using the external photon conversion, and combine it with S_{K^{*}gamma} from B^0 --> K^{*0}(--> K^0_S pi^0) gamma decays. This offers a promising way of determining the hypothetical right-handed current amplitude and phase beyond the standard model.

hep-ex↗
arXiv2002

|Vcb| and |Vub| measurements at Belle

In this paper, we report on the results of the |Vcb| and |Vub| measurements obtained from studies of inclusive and exclusive semileptonic decays using 30fb^-1 of e^+e^- collision data collected by the Belle detector at KEKB.

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