A5055484840- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Computational Physics and Python Applications
- Gyrotron and Vacuum Electronics Research
- Radiation Detection and Scintillator Technologies
- Astrophysics and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Nuclear Physics and Applications
- Distributed and Parallel Computing Systems
- Rare-earth and actinide compounds
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- CCD and CMOS Imaging Sensors
- Radioactive Decay and Measurement Techniques
- Advanced X-ray Imaging Techniques
The University of Tokyo
2009-2025
High Energy Accelerator Research Organization
2010-2024
Tokyo Institute of Technology
2002-2024
Kavli Institute for the Physics and Mathematics of the Universe
2015-2024
Tokyo University of Science
2003-2024
KEK Accelerator Laboratory
2024
Niigata University
2024
The Graduate University for Advanced Studies, SOKENDAI
2024
Tsinghua University
2019
Kyoto University
2004-2018
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.
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 is under construction, to increase luminosity by two orders magnitude during a three-year shutdown, with ultimate goal 8E35 /cm^2 /s luminosity. To exploit increased luminosity, been proposed. A new international collaboration Belle-II, being formed. Technical Design Report presents physics motivation, basic methods accelerator upgrade, as...
We propose the Hyper-Kamiokande (Hyper-K) detector as a next generation underground water Cherenkov detector. It will serve far of long baseline neutrino oscillation experiment envisioned for upgraded J-PARC, and capable observing -- beyond sensitivity Super-Kamiokande (Super-K) proton decays, atmospheric neutrinos, neutrinos from astronomical origins. The design Hyper-K is based on highly successful Super-K, taking full advantage well-proven technology. (to be continued)
The machine commissioning of KEKB started in December 1998 and its operation was terminated at the end June 2010 to upgrade SuperKEKB. In this paper, we summarize history show achievements made there.
The SuperKEKB project requires a positron and electron collider with peak luminosity of 8 × 1035 cm−2 s−1. This is 40 times that the KEKB B-factory, which operated for 11 years up to 2010. an asymmetry-energy double-ring collider; beam energy (LER) 4 GeV (HER) 7 GeV. An extremely small beta function at interaction point (IP) low emittance are necessary. In addition, in order achieve target luminosity, large horizontal crossing angle between two colliding beams adopted, as bunch length much...
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.
We report the observation of prompt J/psi via double cc; production from e+e- continuum. In this process one pair fragments into a meson while remaining either produces charmonium state or open charm. Both cases have been experimentally observed. find cross sections sigma[e+e- -->J/psieta(c)(gamma)]xB(eta(c)-->>or=4 charged)=(0.033(+0.007)(-0.006)+/-0.009) pb and sigma(e+e- -->J/psiD(*+)X)=(0.53(+0.19)(-0.15)+/-0.14) infer -->J/psicc;)/sigma(e+e- -->J/psiX)=0.59(+0.15)(-0.13)+/-0.12. These...
We report the results of a study charged B decays to D+- pi-+ and D*+- final states using complete D(*) reconstruction. The contributions two-body => D** pi with narrow (j=3/2) broad (j=1/2) have been determined masses widths four measured. This is first observation D*0_0 D'0_1 mesons. analysis based on data sample 65 million barB pairs collected in Belle experiment.
We report the first observation of B-->Dmacr;D(sJ)(2317) and B-->Dmacr;D(sJ)(2457) decays based on 123.8x10(6) BBmacr; events collected with Belle detector at KEKB. observe D(sJ)(2317) decay to D(s)pi(0) D(sJ)(2457) D(*)(s)pi(0) D(s)gamma final states. also set 90% C.L. upper limits for D(sJ)(2317)-->D(*)(s)gamma, D(sJ)(2457)-->D(*)(s)gamma, D(sJ)(2457)-->D(s)pi(0), D(sJ)(2457)-->D(s)pi(+)pi(-).
We report the first observation of a charmoniumlike state recoiling from J/psi in inclusive process e+e- -->J/psi+anything at mass (3.943+/-0.006+/-0.006) GeV/c{2}. also observe decay this into D*D[over ] and determine its intrinsic width to be less than 52 MeV/c{2} 90% C.L. These results are obtained 357 fb{-1} data sample collected with Belle detector near Upsilon(4S) resonance, KEKB asymmetric-energy collider.
We report the first observation of two charmed strange baryons that decay into Lambda(c)(+)Kappa(-)pi(+). The broader states is measured to have a mass 2978.5+/-2.1+/-2.0 MeV/c2 and width 43.5+/-7.5+/-7.0 MeV/c2. narrow state are be 3076.7+/-0.9+/-0.5 MeV/c;{2} 6.2+/-1.2+/-0.8 MeV/c2, respectively. also perform search for isospin partner Lambda(c)(+)Kappa(0)/(s)pi(-) observe significant signal at 3082.8+/-1.8+/-1.5 data used this analysis were accumulated or near Upsilon(4S) resonance, using...
We report on a search for new resonant states in the process γγ→D¯¯¯D. A candidate C-even charmonium state is observed vicinity of 3.93 GeV/c2. The production rate and angular distribution γγ center-of-mass frame suggest that this previously unobserved χ′c2, 23P2 state.Received 15 December 2005DOI:https://doi.org/10.1103/PhysRevLett.96.082003©2006 American Physical Society
We have investigated the resistivity $(\ensuremath{\rho}),$ thermoelectric power (TEP), and Hall coefficient ${(R}_{H})$ on high-quality single crystals of $R{\mathrm{Fe}}_{4}{\mathrm{P}}_{12}.$ TEP in ${\mathrm{CeFe}}_{4}{\mathrm{P}}_{12}$ is extremely large $(\ensuremath{\sim}0.5$ mV/K at 290 K) with a peak $\ensuremath{\sim}0.75$ around 65 K. The mobility also shows $\ensuremath{\sim}65$ K, suggesting carriers heavy masses developed lower temperatures related to f-hybridized band. Both Pr...
We report a fully inclusive measurement of the flavor changing neutral current decay b --> sgamma in energy range 1.8 GeV < or = E*gamma 2.8 GeV, covering 95% total spectrum. Using 140 fb(-1), we obtain B(b sgamma) (3.55+/-0.32(+0.30+0.11)(-0.31-0.07)) x 10(-4), where errors are statistical, systematic, and from theory corrections. also measure first second moments photon spectrum above (Egamma) 2.292+/-0.026+/-0.034 (E2gamma) - (Egamma)2 0.0305+/-0.0074+/-0.0063 GeV2, statistical systematic.
We present an improved measurement of the standard model CP violation parameter $\mathrm{sin}2{\ensuremath{\varphi}}_{1}$ (also known as $\mathrm{sin}2\ensuremath{\beta})$ based on a sample $85\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at $\ensuremath{\Upsilon}(4S)$ resonance with Belle detector KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral B meson is reconstructed in $J/\ensuremath{\psi}{K}_{S}^{0},$...
The Collins effect connects transverse quark spin with a measurable azimuthal dependence in the yield of hadronic fragments around quark's momentum vector. Using two different reconstruction methods, we find evidence statistically significant asymmetries for charged pion pairs e(+)e(-) annihilation at center-of-mass energy 10.52 GeV, which can be attributed to polarization primordial quarks. measurement was performed using sample 79 x 10(6) events collected Belle detector.
We observe evidence for D0−¯¯¯D0 mixing by measuring the difference in apparent lifetime when a D0 meson decays to CP eigenstates K+K− and π+π− it final state K−π+. find relative of lifetimes yCP be [1.31±0.32(stat)±0.25(syst)]%, 3.2 standard deviations from zero. also search asymmetry between ¯¯¯D0 decays; no violation is found. These results are based on 540 fb−1 data recorded Belle detector at KEKB e+e− collider.Received 31 March 2007DOI:https://doi.org/10.1103/PhysRevLett.98.211803©2007...
We report the first observation of a near-threshold enhancement in D(0)D[over](0)pi(0) system from B-->D(0)D[over](0)pi(0)Kappa decays using 414 fb(-1) data sample collected at Upsilon(4S) resonance. The peaks mass M=3875.2+/-0.7(+0.3)/(-1.6) +/-0.8 MeV/c2 and branching fraction for events peak is B(B-->D(0)D[over](0)pi(0)Kappa)=(1.22+/-0.31(+0.23)/(-0.30))x10(-4). were with Belle detector KEKB energy-asymmetric e+ e- collider.