T. Hara

ORCID: 0000-0002-4321-0417
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About
Contact & Profiles
Research Areas
  • Particle physics theoretical and experimental studies
  • Quantum Chromodynamics and Particle Interactions
  • High-Energy Particle Collisions Research
  • Neutrino Physics Research
  • Astrophysics and Cosmic Phenomena
  • Dark Matter and Cosmic Phenomena
  • Particle Detector Development and Performance
  • Particle Accelerators and Free-Electron Lasers
  • Medical Imaging Techniques and Applications
  • Gamma-ray bursts and supernovae
  • Atomic and Subatomic Physics Research
  • Computational Physics and Python Applications
  • Radiation Detection and Scintillator Technologies
  • Superconducting Materials and Applications
  • Black Holes and Theoretical Physics
  • Pulsars and Gravitational Waves Research
  • Cosmology and Gravitation Theories
  • Nuclear physics research studies
  • Advanced X-ray and CT Imaging
  • Muon and positron interactions and applications
  • Particle accelerators and beam dynamics
  • Radiation Dose and Imaging
  • Distributed and Parallel Computing Systems
  • Advanced Data Storage Technologies
  • Semiconductor materials and interfaces

High Energy Accelerator Research Organization
2015-2024

Kobe University
2013-2023

The Graduate University for Advanced Studies, SOKENDAI
2014-2023

Kashiwa Municipal Hospital
2006-2019

Istituto Nazionale di Fisica Nucleare, Sezione di Bari
1998-2018

University of the Basque Country
2013-2018

Laboratoire d’Annecy de Physique des Particules
2018

Institut National de Physique Nucléaire et de Physique des Particules
2018

Centre National de la Recherche Scientifique
2018

Universitat de Barcelona
2018

We report the observation of a narrow charmoniumlike state produced in exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has mass 3872.0+/-0.6(stat)+/-0.5(syst) MeV, value that is very near M(D0)+M(D(*0)) threshold. The results are based on an analysis 152M B-Bmacr; events collected at Upsilon(4S) resonance Belle detector KEKB collider. signal statistical significance excess 10sigma.

10.1103/physrevlett.91.262001 article EN Physical Review Letters 2003-12-23

The Double Chooz experiment presents an indication of reactor electron antineutrino disappearance consistent with neutrino oscillations. An observed-to-predicted ratio events 0.944±0.016(stat)±0.040(syst) was obtained in 101 days running at the nuclear power plant France, two 4.25 GW(th) reactors. results were from a single 10 m(3) fiducial volume detector located 1050 m cores. flux prediction used Bugey4 measurement after correction for differences core composition. deficit can be...

10.1103/physrevlett.108.131801 article EN publisher-specific-oa Physical Review Letters 2012-03-28

The K2K experiment observes indications of neutrino oscillation: a reduction $\nu_\mu$ flux together with distortion the energy spectrum. Fifty-six beam events are observed in Super-Kamiokande (SK), 250 km from production point, an expectation $80.1^{+6.2}_{-5.4}$. Twenty-nine one ring $\mu$-like used to reconstruct spectrum, which is better matched expected spectrum oscillation than without. probability that at SK explained by statistical fluctuation without less 1%.

10.1103/physrevlett.90.041801 article EN Physical Review Letters 2003-01-30

Results from 1036 days of solar neutrino data accumulated in the upgraded Kamiokande detector (Kamiokande III) are presented. The $^{8}\mathrm{B}$ flux observed III is ${2.82}_{\ensuremath{-}0.24}^{+0.25}$ (stat) \ifmmode\pm\else\textpm\fi{} 0.27 (syst) \ifmmode\times\else\texttimes\fi{} ${10}^{6}$ ${\mathrm{cm}}^{\ensuremath{-}2}$${\mathrm{s}}^{\ensuremath{-}1}$; combined II and (2079 total) 2.80 0.19 0.33 ${\mathrm{cm}}^{\ensuremath{-}2}$${\mathrm{s}}^{\ensuremath{-}1}$, which 49% to 64%...

10.1103/physrevlett.77.1683 article EN Physical Review Letters 1996-08-26

We report a measurement of the branching fraction ratios R(D(*)) Bbar -> D(*) tau- nubar_tau relative to D()* l- nubar_l (where l = e or mu) using full Belle data sample 772 x 10^6 BBbar pairs collected at Y(4S) resonance with detector KEKB asymmetric-energy e+e- collider. The measured values are R(D)= 0.375 +- 0.064(stat.) 0.026(syst.) and R(D*) 0.293 0.038(stat.) 0.015(syst.). analysis uses hadronic reconstruction tag-side B meson purely leptonic tau decays. results consistent earlier...

10.1103/physrevd.92.072014 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2015-10-26

We present measurements of nu_mu disappearance in K2K, the KEK to Kamioka long-baseline neutrino oscillation experiment. One hundred and twelve beam-originated events are observed fiducial volume Super-Kamiokande with an expectation 158.1^{+9.2}_{-8.6} without oscillation. A distortion energy spectrum is also seen 58 single-ring muon-like reconstructed energies. The probability that observations explained by for no 0.0015% (4.3sigma). In a two flavor scenario, allowed Delta m^2 region at...

10.1103/physrevd.74.072003 article EN Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2006-10-12

We report the observation of two narrow structures in mass spectra pi+-Y(nS) (n=1,2,3) and pi+-hb(mP)(m$ (m=1,2) pairs that are produced association with a single charged pion Y(5S) decays. The measured masses widths averaged over five final states M_1=(10607.2+-2.0) MeV/c2, Gamma_1=(18.4+-2.4) MeV M_2=(10652.2+-1.5) Gamma_2=(11.5+-2.2) MeV. results obtained 121.4 1/fb data sample collected Belle detector vicinity resonance at KEKB asymmetric-energy e+e- collider.

10.1103/physrevlett.108.122001 article EN publisher-specific-oa Physical Review Letters 2012-03-20

We present a measurement of the standard model $\mathrm{CP}$ violation parameter $\mathrm{sin}2{\ensuremath{\varphi}}_{1}$ based on $29.1{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected at $\ensuremath{\Upsilon}(4S)$ resonance with Belle detector KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral $B$ meson is fully reconstructed as $J/\ensuremath{\psi}{K}_{S}$, $\ensuremath{\psi}(2S){K}_{S}$, ${\ensuremath{\chi}}_{c1}{K}_{S}$, ${\ensuremath{\eta}}_{c}{K}_{S}$,...

10.1103/physrevlett.87.091802 article EN Physical Review Letters 2001-08-14

A bstract The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured velocity of neutrinos from CERN CNGS beam over a baseline about 730 km. measurement is based on data taken by in years 2009, 2010 and 2011. Dedicated upgrades timing system detector, as well high precision geodesy campaign for baseline, allowed reaching comparable systematic statistical accuracies. An arrival time muon with respect to one computed assuming speed light vacuum $ \left( {6.5\pm...

10.1007/jhep10(2012)093 article EN cc-by Journal of High Energy Physics 2012-10-01

A distinct peak is observed in the ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\psi}}^{\ensuremath{'}}$ invariant mass distribution near 4.43 GeV $B\ensuremath{\rightarrow}K{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\psi}}^{\ensuremath{'}}$ decays. fit using a Breit-Wigner resonance shape yields and width of $M=4433\ifmmode\pm\else\textpm\fi{}4(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}$...

10.1103/physrevlett.100.142001 article EN Physical Review Letters 2008-04-08

The T2K experiment has observed electron neutrino appearance in a muon beam produced 295 km from the Super-Kamiokande detector with peak energy of 0.6 GeV. A total 28 events were detected an distribution consistent signal, corresponding to significance 7.3σ when compared 4.92±0.55 expected background events. In Pontecorvo-Maki-Nakagawa-Sakata mixing model, signal depends on several parameters including three angles θ12, θ23, θ13, mass difference Δm232 and CP violating phase δCP. this...

10.1103/physrevlett.112.061802 article EN Physical Review Letters 2014-02-10

We present results for ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ oscillation in the KEK to Kamioka (K2K) long-baseline neutrino experiment. K2K uses an accelerator-produced beam with a mean energy of 1.3 GeV directed at Super-Kamiokande detector. observed energy-dependent disappearance ${\ensuremath{\nu}}_{\ensuremath{\mu}}$, which we presume have oscillated ${\ensuremath{\nu}}_{\ensuremath{\tau}}$. The probability that would observe these if there is no 0.0050% ($4.0\ensuremath{\sigma}$).

10.1103/physrevlett.94.081802 article EN Physical Review Letters 2005-03-03

A bstract The OPERA neutrino experiment is designed to perform the first observation of oscillations in direct appearance mode ν μ → τ channel, via detection -leptons created charged current interactions. detector, located underground Gran Sasso Laboratory, consists an emulsion/lead target with average mass about 1.2 kt, complemented by electronic detectors. It exposed CERN Neutrinos beam, a baseline 730 km and mean energy 17 GeV. candidate event analysis 2008-2009 sample have been reported...

10.1007/jhep11(2013)036 article EN cc-by Journal of High Energy Physics 2013-11-01

We report a measurement of the ratio ${\cal R}(D^*) = {\cal B}(\bar{B}^0 \rightarrow D^{*+} \tau^- \bar{\nu}_{\tau})/{\cal \ell^- \bar{\nu}_{\ell})$, where $\ell$ denotes an electron or muon. The results are based on data sample containing $772\times10^6$ $B\bar{B}$ pairs recorded at $\Upsilon(4S)$ resonance with Belle detector KEKB $e^+ e^-$ collider. select $B^0 \bar{B}^0$ by reconstructing both $B$ mesons in semileptonic decays to $D^{*\mp} \ell^{\pm}$. measure R}(D^*)= 0.302 \pm...

10.1103/physrevd.94.072007 article EN publisher-specific-oa Physical review. D/Physical review. D. 2016-10-27

The Double Chooz experiment has observed 8249 candidate electron antineutrino events in 227.93 live days with 33.71 GW-ton-years ($\mathrm{\text{reactor power}}\ifmmode\times\else\texttimes\fi{}\mathrm{\text{detector mass}}\ifmmode\times\else\texttimes\fi{}\mathrm{\text{live time}}$) exposure using a $10.3\text{ }\text{ }{\mathrm{m}}^{3}$ fiducial volume detector located at 1050 m from the reactor cores of nuclear power plant France. expectation case ${\ensuremath{\theta}}_{13}=0$ is 8937...

10.1103/physrevd.86.052008 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2012-09-18

We present a measurement of angular observables and test lepton flavor universality in the $B\ensuremath{\rightarrow}{K}^{*}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ decay, where $\ensuremath{\ell}$ is either $e$ or $\ensuremath{\mu}$. The analysis performed on data sample corresponding to an integrated luminosity $711\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ containing $772\ifmmode\times\else\texttimes\fi{}1{0}^{6}$ $B\overline{B}$ pairs, collected at...

10.1103/physrevlett.118.111801 article EN publisher-specific-oa Physical Review Letters 2017-03-13

We report on measurements of neutrino oscillation using data from the T2K long-baseline experiment collected between 2010 and 2013. In an analysis muon disappearance alone, we find following estimates 68% confidence intervals for two possible mass hierarchies: Normal Hierarchy: $\sin^2\theta_{23}=0.514^{+0.055}_{-0.056}$ $\Delta m^2_{32}=(2.51\pm0.10)\times 10^{-3}$ eV$^2$/c$^4$ Inverted $\sin^2\theta_{23}=0.511\pm0.055$ m^2_{13}=(2.48\pm0.10)\times The accounts multi-nucleon mechanisms in...

10.1103/physrevd.91.072010 article EN cc-by Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2015-04-29

The Double Chooz experiment presents improved measurements of the neutrino mixing angle θ 13 using data collected in 467.90 live days from a detector positioned at an average distance 1050 m two reactor cores nuclear power plant. Several novel techniques have been developed to achieve significant reductions backgrounds and systematic uncertainties with respect previous publications, whereas efficiency $$ {\overline{\nu}}_e signal has increased. value is measured be sin2 2θ = 0.090 − 0.029 +...

10.1007/jhep10(2014)086 article EN cc-by Journal of High Energy Physics 2014-10-01

The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an off-axis muon beam with a peak energy of about 0.6 GeV that originates at the J-PARC accelerator facility. Interactions neutrinos are observed near detectors placed 280 m from production target and far detector -- Super-Kamiokande (SK) located 295 km away. flux prediction is essential part successful interaction rates T2K important input to oscillation cross section measurements. A FLUKA GEANT3 based simulation...

10.1103/physrevd.87.012001 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2013-01-02

New data from the T2K neutrino oscillation experiment produce most precise measurement of mixing parameter ${\ensuremath{\theta}}_{23}$. Using an off-axis beam with a peak energy 0.6 GeV and set corresponding to $6.57\ifmmode\times\else\texttimes\fi{}1{0}^{20}$ protons on target, has fit energy-dependent ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ probability determine parameters. The 68% confidence limit ${\mathrm{sin}}^{2}({\ensuremath{\theta}}_{23})$ is...

10.1103/physrevlett.112.181801 article EN Physical Review Letters 2014-05-08

We report the observation of a near-threshold enhancement in omegaJ/psi invariant mass distribution for exclusive B-->KomegaJ/psi decays. The results are obtained from 253 fb(-1) data sample that contains 275 x 10(6) BB pairs were collected near Upsilon(4S) resonance with Belle detector at KEKB asymmetric energy e(+)e(-) collider. statistical significance is estimated to be greater than 8sigma.

10.1103/physrevlett.94.182002 article EN Physical Review Letters 2005-05-12
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