T. Nakamura
A5102890107- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Superconducting Materials and Applications
- Particle Detector Development and Performance
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Crystallography and molecular interactions
- Gyrotron and Vacuum Electronics Research
- Inflammatory mediators and NSAID effects
- Advanced Semiconductor Detectors and Materials
- Helicobacter pylori-related gastroenterology studies
- Nuclear reactor physics and engineering
- Neutrino Physics Research
- Radiation Therapy and Dosimetry
- Magnetic Properties and Synthesis of Ferrites
- Dark Matter and Cosmic Phenomena
- Photonic and Optical Devices
- Magnetic properties of thin films
- Electromagnetic wave absorption materials
Japan Atomic Energy Agency
2014-2024
Japan Proton Accelerator Research Complex
2012-2024
High Energy Accelerator Research Organization
2003-2023
The University of Tokyo
2002-2022
Hyogo Medical University
2022
SPring-8
2002-2021
RIKEN
2001-2017
RIKEN Nishina Center
2011-2017
Hiroshima University
2008-2015
Tokyo Institute of Technology
2001-2014
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...
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 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 measurements of the properties D(+)(sJ)(2317) and D(+)(sJ)(2457) resonances produced in continuum e(+)e(-) annihilation near sqrt[s]=10.6 GeV. The analysis is based on an 86.9 fb(-1) data sample collected with Belle detector at KEKB. determine masses to be M(D(+)(sJ)(2317))=2317.2+/-0.5(stat)+/-0.9(syst) MeV/c(2) M(D(+)(sJ)(2457))=2456.5+/-1.3(stat)+/-1.3(syst) MeV/c(2). observe radiative decay mode D(+)(sJ)(2457)-->D(+)(s)gamma dipion D(+)(sJ)(2457)-->D(+)(s)pi(+)pi(-) their...
Polycrystalline hexagonal ferrites (Y, Z and W-phases) were prepared by the usual ceramic sintering. Their complex permeability spectra natural resonance type, numerically separated into spin rotational domain wall motion components. For component, it was found that Snoek's product values of them far beyond spinel ferrite. It enabled us to design thin electromagnetic wave absorbers for quasimicrowave region.
We have performed a search for the lepton-flavor-violating decay tau -> mu gamma using data sample of 86.3fb^{-1} accumulated by Belle detector at KEK. No evidence signal is seen, and we set an upper limit branching fraction B(tau gamma) < 3.1 x 10^{-7} 90% confidence level.
Ni–Zn–Co ferrite films were deposited by the spin-spray plating from an aqueous solution. Film with optimized Zn and Co contents (i.e., Ni0.22Zn0.52Co0.03Fe2.23O4) exhibited real permeability μr′ higher than 260 at frequencies up to 130 MHz, imaginary μr″ 100 in extremely wide frequency range MHz 1 GHz. Prepared very low temperature of 90 °C without postdeposition annealing, these are promising be actually applied electromagnetic noise suppressors which directly cover source elements on...
The authors have fabricated oxide-confined vertical-cavity surface-emitting lasers with metal apertures exhibiting a spatial mode filtering effect. Single-mode continuous-wave output is enhanced up to 3.4 mW by this effect for AlGaAs-based 780-nm 3.5-μm-diameter oxide aperture. From numerical calculations, the round-trip loss difference between zeroth- and first-order optical modes as function of aperture size indicates that there an optimum point; 4-μm suitable higher order suppression...
Mixings of four-quark components in the nonsinglet scalar mesons are studied QCD sum rules. We propose a formulation to evaluate cross correlators $q\overline{q}$ and $qq\overline{q}\overline{q}$ operators define mixings different Fock states rule. It is applied mesons, ${a}_{0}$ ${K}_{0}^{*}$. found that predict lower masses than occupy about 70%--90% lowest mass states.
We present results on the production of hadrons in collisions 400-GeV/c protons with beryllium, copper, and tungsten nuclei. The data cover region from 5.6 to 8.0 GeV/c transverse momentum final-state hadron 73° 102° proton-nucleon center-of-momentum frame angle theta*. restriction values xT (xT=2pT/ √s ) greater than 0.4 enriches sample hard valence quarks. Asymmetries about theta*=90° reflect presence neutrons target variation atomic-weight dependence parameter α is discussed context...