Y. Nagasaka
A5015861317- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Cosmology and Gravitation Theories
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Distributed and Parallel Computing Systems
- Astrophysics and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Advanced Data Storage Technologies
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Superconducting Materials and Applications
- Radiation Detection and Scintillator Technologies
- Particle accelerators and beam dynamics
- Muon and positron interactions and applications
- Parallel Computing and Optimization Techniques
- Distributed systems and fault tolerance
- advanced mathematical theories
- Network Traffic and Congestion Control
- Engineering Structural Analysis Methods
Hiroshima Institute of Technology
2015-2024
Laboratoire Leprince-Ringuet
2022
The University of Adelaide
2013-2021
Université Clermont Auvergne
2020
Institut National de Physique Nucléaire et de Physique des Particules
2020
AGH University of Krakow
2019-2020
Centre National de la Recherche Scientifique
2020
Rutherford Appleton Laboratory
2011-2019
University of Copenhagen
2019
Technion – Israel Institute of Technology
2017-2018
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 cross section for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$ between 3.8 and $5.5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is measured using a $548\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected on or near the $\ensuremath{\Upsilon}(4S)$ resonance with Belle detector at KEKB. A peak $4.25\text{ }\mathrm{GeV}/{c}^{2}$, corresponding to so called $Y(4260)$, observed. In addition, there another...
An apparatus for precise and absolute measurement of the thermal conductivity electrically conducting liquids using transient hot-wire method has been developed. In present apparatus, a metallic wire coated with thin electrical insulation layer used as heating element resistance thermometer instead bare wire. The effects on caused by have analysed. analysis, it was found that can be negligibly small if instrument is adequately designed. usability tested to measure an aqueous NaCl solution in...
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 +...
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 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 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 report a measurement of the process $\ensuremath{\gamma}{\ensuremath{\gamma}}^{*}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}$ with $759\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample recorded Belle detector at KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. The pion transition form factor, $F({Q}^{2})$, is measured for kinematical region $4\text{ }{\mathrm{GeV}}^{2}\ensuremath{\lesssim}{Q}^{2}\ensuremath{\lesssim}40\text{ }{\mathrm{GeV}}^{2}$, where...
We report a high-statistics measurement of the branching fraction for tau^- --> pi^- pi^0 nu_tau and invariant mass spectrum produced system using 72.2 fb^-1 data recorded with Belle detector at KEKB asymmetric-energy e^+ e^- collider. The obtained is (25.24 +/- 0.01 0.39)%, where first error statistical second systematic. unfolded used to determine resonance parameters rho(770), rho'(1450), rho"(1700) mesons. also use this estimate hadronic (2pi) contribution anomalous magnetic moment muon...
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.
We present an improved measurement of the branching fraction for electroweak penguin process $B\ensuremath{\rightarrow}{X}_{s}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$, where $\ensuremath{\ell}$ is electron or a muon and ${X}_{s}$ hadronic system containing $s$-quark. The based on sample $152\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ events collected with Belle detector at KEKB energy asymmetric...
The paper describes a method and an instrument to measure the thermal conductivity diffusivity of liquids simultaneously by transient hot-wire method. Though principle this has formerly been known, practical application fluids enabled only high-precision measurement. In present method, can be determined from slope temperature rise against time electrically-heated wire obtained absolute rise. instrument, rise, which is detected as voltage change unbalanced bridge, recorded digital system....
We report the first observations of spin-singlet bottomonium states hb(1P) and hb(2P). The are produced in reaction e+e−→hb(nP)π+π− using a 121.4 fb−1 data sample collected at energies near Υ(5S) resonance with Belle detector KEKB asymmetric-energy e+e− collider. determine M[hb(1P)]=(9898.2+1.1+1.0−1.0−1.1) MeV/c2 M[hb(2P)]=(10 259.8±0.6+1.4−1.0) MeV/c2, which correspond to P-wave hyperfine splittings ΔMHF=(+1.7±1.5) (+0.5+1.6−1.2) respectively. significances hb(2P) 5.5σ 11.2σ, find that...
We report the observation of a new $D_{sJ}$ meson produced in $B^{+} \to \bar{D}^{0} D_{sJ} D^{0} K^{+}$. This state has mass $M=2708 \pm 9 ^{+11}_{-10} \rm{MeV}/{\it c}^{2}$, width $\Gamma = 108 23 ^{+36}_{-31} ~\rm{MeV}/ {\it c}^{2}$ and $1^{-}$ spin-parity. The results are based on an analysis 449 million $B\bar{B}$ events collected at $\Upsilon(4S)$ resonance with Belle detector KEKB asymmetric-energy $e^{+} e^{-}$ collider.
We report on a search for heavy neutrinos in B-meson decays. The results are obtained using data sample that contains 772x10^6 BB-bar pairs collected at the Upsilon(4S) resonance with Belle detector KEKB asymmetric-energy e+e- collider. No signal is observed and upper limits set mixing of left-handed Standard Model mass range 0.5 - 5.0 GeV/c^2.
We report the results of a study exclusive semileptonic decays B->pi0lnu, B->pi+lnu, B->rho0lnu, B->rho+lnu and B->omegalnu, where l represents an electron or muon. The events are tagged by fully reconstructing second B meson in event hadronic decay mode. measured branching fractions Br(B->pi0lnu) = (0.80 +- 0.08 0.04)x10^-4, Br(B->pi+lnu) (1.49 0.09 0.07)x10^-4, Br(B->rho0lnu) (1.83 0.10 0.10)x10^-4, Br(B->rho+lnu) (3.22 0.27 0.24)x10^-4, Br(B->omegalnu) =(1.07 0.16 first error is...
We present a measurement of the charmless semileptonic decay $B^0\to\pi^-\ell^+\nu$ using data sample containing 657$\times 10^6$ $B\bar{B}$ events collected with Belle detector at KEKB asymmetric-energy $e^+e^-$ collider operating near $\Upsilon(4S)$ resonance. determine total branching fraction decay, $\mathcal{B}(B^0\to\pi^-\ell^+\nu)=(1.49\pm 0.04{(\mathrm{stat})}\pm 0.07{(\mathrm{syst})})\times 10^{-4}$. also report new precise differential rate, and extract Cabibbo-Kobayashi-Maskawa...
We report results on the Dalitz analysis of three-body charmless B+→K+π+π− and B+→K+K+K− decays based a 140 fb−1 data sample collected with Belle detector. Measurements branching fractions for quasi-two-body to scalar-pseudoscalar states: B+→f0(980)K+, B+→K∗0(1430)0π+, vector-pseudoscalar B+→K∗(892)0π+, B+→ρ0K+, B+→ϕK+ are presented. Upper limits some pseudoscalar-tensor final states reported. also measurement B+→χc0K+ fraction in two χc0 channels: χc0→π+π− χc0→K+K−.8 MoreReceived 23...
We present a new analysis of double charmonium production in e^+ e^- annihilation. The observation the processes -> J/psi eta_c, chi_c0, and eta_c(2S) is confirmed using dataset more than three times larger that Belle's previous report, no evidence for process found. perform an angular eta_c set upper limit on J/psi. Processes type psi(2S) (cc)_res have been observed first time; their rates are found to be comparable those processes.
We have searched for a CP violation signature arising from an electric dipole moment (dτ) of the τ lepton in e+e−→τ+τ− reaction. Using optimal observable method and 29.5 fb−1 data collected with Belle detector at KEKB collider s=10.58 GeV, we find Re(dτ)=(1.15±1.70)×10−17 ecm Im(dτ)=(−0.83±0.86)×10−17 set 95% confidence level limits −2.2×10−17<Re(dτ)<4.5×10−17 −2.5×10−17<Im(dτ)<0.8×10−17 ecm.
We report an observation of the decay $B^0\to D^{*-} \tau^+ \nu_{\tau}$ in a data sample containing $535\times10^6$ $B\bar{B}$ pairs collected with Belle detector at KEKB asymmetric-energy $e^+e^-$ collider. find signal significance 5.2 standard deviations and measure branching fraction $\mathcal{B}(B^0\to \tau ^+ \nu_{\tau})=(2.02 ^{+0.40}_{-0.37} (stat) \pm 0.37 (syst)) % $. This is first exclusive $B$ $b \to c transition.
We report the observation of an isotriplet excited charmed baryons, decaying into Lambda(+)(c)pi(-), Lambda(+)(c)pi(0), and Lambda(+)(c)pi(+). measure mass differences M(Lambda(+)(c)pi)-M(Lambda(+)(c)) widths to be 515.4(+3.2+2.1)(-3.1-6.0) MeV/c(2), 61(+18+22)(-13-13) MeV for neutral state; 505.4(+5.8+12.4)(-4.6-2.0) 62(+37+52)(-23-38) charged 514.5(+3.4+2.8)(-3.1-4.9) 75(+18+12)(-13-11) doubly state, where uncertainties are statistical systematic, respectively. These results obtained from...