H. Ohnìshì
A5013531050- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Semiconductor Quantum Structures and Devices
- Particle Detector Development and Performance
- Nuclear physics research studies
- Advancements in Semiconductor Devices and Circuit Design
- Atomic and Subatomic Physics Research
- Quantum and electron transport phenomena
- Radiation Detection and Scintillator Technologies
- Nuclear reactor physics and engineering
- Semiconductor materials and devices
- Superconducting Materials and Applications
- Acute Myeloid Leukemia Research
- Radio Frequency Integrated Circuit Design
- Photonic and Optical Devices
- Dark Matter and Cosmic Phenomena
- Quantum, superfluid, helium dynamics
- Semiconductor Lasers and Optical Devices
- High-pressure geophysics and materials
- Mycobacterium research and diagnosis
- Acute Lymphoblastic Leukemia research
- Nuclear Physics and Applications
- Physics of Superconductivity and Magnetism
- X-ray Diffraction in Crystallography
Kyorin University
2016-2025
Tohoku University
2007-2024
Istituto Nazionale di Fisica Nucleare, Sezione di Milano
2023
Politecnico di Milano
2023
Consorzio di Bioingegneria e Informatica Medica
2023
Kyorin University Hospital
2014-2023
RIKEN
2008-2022
High Energy Accelerator Research Organization
2011-2022
Osaka University
1987-2022
Nippon Soken (Japan)
2018-2022
We report on a precision measurement of low-mass muon pairs in 158 AGeV indium-indium collisions at the CERN SPS. A significant excess is observed above yield expected from neutral meson decays. The unprecedented sample size 360 000 dimuons and good mass resolution about 2% allow us to isolate by subtraction decay sources. shape resulting spectrum consistent with dominant contribution...
Transverse mass spectra of pions, kaons, and protons from the symmetric heavy-ion collisions 200 $A$ GeV $\mathrm{S}+\mathrm{S}$ 158 $\mathrm{Pb}+\mathrm{Pb}$, measured in NA44 focusing spectrometer at CERN, are presented. The dependence slope parameters provides evidence collective transverse flow expansion system induced central collisions.
We investigated the current-voltage characteristics of double barrier, resonant tunneling structure, using a self-consistent method. note significance effects band bending and buildup space charge in quantum well. For peak current, our calculated results agree with measured very However, valley current is much greater than values.
The NA60 experiment at the CERN SPS has studied low-mass muon pairs in 158A GeV In-In collisions. mass and pT spectra associated with peripheral collisions can quantitatively be described by known neutral meson decays. high data quality allowed to remeasure electromagnetic transition form factors of Dalitz decays η-> μ^+μ^-γand ω-> μ^+μ^-π^0. Using usual pole approximation F = (1-M_{μμ}^{2}/Λ^{2})^{-1} for factors, we find Λ^{-2} (in GeV^{-2}) 1.95+-0.17(stat.)+-0.05(syst.) ηand...
The NA60 experiment studies muon pair production at the CERN Super Proton Synchrotron. In this Letter we report on a precision measurement of J/ψ in In-In collisions. We have studied centrality distribution, and compared it with one expected if absorption cold nuclear matter were only active suppression mechanism. For collisions involving more than ∼80 participant nucleons, find that an extra is present. This result qualitative agreement previous Pb-Pb measurements by NA50 experiment, but no...
The yield of muon pairs in the invariant mass region 1
ObjectivesMatrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a fast and reliable method for the identification of bacteria. A MALDI Sepsityper kit generally used to prepare samples obtained directly from culture bottles. However, relatively high cost this major obstacle introducing into routine clinical use. In study, accuracies three different preparation methods rapid direct bacteria positive blood bottles by MALDI-TOF MS analysis were...
We observed a distinct peak in the Λp invariant mass spectrum of He3(K−,Λp)n, well below mK+2mp, i.e., threshold K− to be bound two protons. By selecting relatively large momentum-transfer region q=350∼650 MeV/c, one can kinematically separate from quasi-free process, K‾N→K‾N followed by non-resonant absorption spectator-nucleons K‾NN→ΛN. found that simplest fit gives us Breit–Wigner pole position at BKpp=47±3(stat.)−6+3(sys.) MeV having width ΓKpp=115±7(stat.)−20+10(sys.) MeV, and S-wave...
We have measured the Balmer-series x-rays of kaonic $^4$He atoms using novel large-area silicon drift x-ray detectors in order to study low-energy $\bar{K}$-nucleus strong interaction. The energy $3d \to 2p$ transition was determined be 6467 $\pm$ 3 (stat) 2 (syst) eV. resulting strong-interaction energy-level shift is agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.
The NA60 experiment at the CERN SPS has studied low-mass dimuon production in 158A GeV In-In collisions. An excess of pairs above known meson decays been reported before. We now present precision results on associated transverse momentum spectra. slope parameter Teff extracted from spectra rises with mass up to ρ, followed by a sudden decline above. While initial rise is consistent expectations for radial flow hadronic decay source, signals transition an emission source much smaller flow....
The effect of Si doping profile on I–V characteristics an AlGaAs/GaAs resonant tunneling barrier (RTB) structure was studied by changing the thickness undoped GaAs “spacer” layer placed adjacent to RTB. We found that peak and valley current density in negative differential resistance region at 77 K depends strongly spacer layer. By using a 50 Å, we achieved diode with highest 2×10 4 A/cm 2 good peak-to-valley ratio 3.5 K.
The NA60 experiment at the CERN SPS has measured muon pairs with unprecedented precision in 158A GeV In-In collisions. A strong excess of above known sources is observed whole mass region 0.2 rho -> mu+mu- annihilation. associated spectral function shows a broadening, but essentially no shift mass. For M>1 GeV, found to be prompt, not due enhanced charm production, pronounced differences Drell-Yan pairs. slope parameter Teff transverse momentum spectra rises up rho, followed by sudden...
The NA60 experiment studied low-mass muon pair production in proton–nucleus (p–A) collisions using a 400 GeV proton beam at the CERN SPS. dimuon spectrum is well described by superposition of two-body and Dalitz decays light neutral mesons η, ρ, ω, η′ ϕ, no evidence in-medium effects found. A new high-precision measurement electromagnetic transition form factors η ω was performed, profiting from 10 times larger data sample than peripheral In–In previously collected NA60. Using...
Emission of muonium (|$\mu ^+e^-$|) atoms from a laser-processed aerogel surface into vacuum was studied for the first time. Laser ablation used to create hole-like regions with diameter about 270 |$\mu $|m in triangular pattern hole separation range 300–500 $|m. The emission probability sample is at least eight times higher than uniform one.
The SIDDHARTA-2 collaboration is performing research in the field of kaonic atoms spectroscopy. In this work, following an introduction on and their importance for development low-energy strong interaction theories, first result experiment (kaonic helium) presented. This measurement was promising view main goal experiment, i.e. deuterium transitions to 1s level, important model kaon-nucleon interaction. last part paper future plans measure new key quantities with beyond stat-of-the-art...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpontaneous and olefin-promoted reductive elimination of .eta.3-allyl(organo)palladium(II) complexes: mechanistic molecular orbital analysisHideo Kurosawa, Mitsuhiro Emoto, Hiroaki Ohnishi, Kunio Miki, Nobutami Kasai, Kazuyuki Tatsumi, Akira NakamuraCite this: J. Am. Chem. Soc. 1987, 109, 21, 6333–6340Publication Date (Print):October 1, 1987Publication History Published online1 May 2002Published inissue 1 October...
Light electron effective mass was found to be a very important parameter for improving the negative differential resistance (NDR) of resonant tunneling barrier (RTB) structure. An InAlAs (41 Å)/InGaAs (61.5 Å)/InAlAs Å) RTB structure, lattice-matched Ink, has been grown first time by MBE and dramatically improved NDR achieved. Peak current density as high 2.2×10 4 A/cm 2 with an excellent peak-to-valley ratio 11.7 obtained at 77 K, which is best data ever reported so far any structures.