T. Fusayasu
A5014960558- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Nuclear reactor physics and engineering
- Radiation Detection and Scintillator Technologies
- Nuclear physics research studies
- Statistical Methods and Bayesian Inference
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Pediatric Urology and Nephrology Studies
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Neutrino Physics Research
- CCD and CMOS Imaging Sensors
- Cold Atom Physics and Bose-Einstein Condensates
- Stochastic processes and statistical mechanics
- Distributed and Parallel Computing Systems
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Life Cycle Costing Analysis
- Muon and positron interactions and applications
- Theoretical and Computational Physics
- Transition Metal Oxide Nanomaterials
Saga University
2016-2025
GSI Helmholtz Centre for Heavy Ion Research
2023-2024
A. Alikhanyan National Laboratory
2022-2024
Abilene Christian University
2023
Augustana University
2023
Charles University
2020-2023
PHENIX laboratory
2020-2023
Banaras Hindu University
2020-2023
Bhabha Atomic Research Centre
2023
Nagasaki Institute of Applied Science
2012-2022
The second Fourier component ${v}_{2}$ of the azimuthal anisotropy with respect to reaction plane is measured for direct photons at midrapidity and transverse momentum (${p}_{T}$) $1--12\text{ }\text{ }\mathrm{GeV}/c$ in $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{NN}}=200\text{ }\mathrm{GeV}$. Previous measurements this quantity hadrons ${p}_{T}<6\text{ indicate that medium behaves like a nearly perfect fluid, while ${p}_{T}>6\text{ reduced interpreted terms path-length dependence...
The momentum distribution of electrons from decays heavy flavor (charm and bottom) for midrapidity |y|<0.35 in p+p collisions at s=200 GeV has been measured by the PHENIX experiment BNL Relativistic Heavy Ion Collider over transverse range 0.3<pT<9 GeV/c. Two independent methods have used to determine heavy-flavor yields, results are good agreement with each other. A fixed-order-plus-next-to-leading-log perturbative QCD calculation agrees data within theoretical experimental uncertainties,...
Heavy quarkonia are observed to be suppressed in relativistic heavy-ion collisions relative their production $p+p$ scaled by the number of binary collisions. In order determine if this suppression is related color screening these states produced medium, one needs account for other nuclear modifications including those cold matter. paper, we present new measurements from PHENIX 2007 data set $J/\ensuremath{\psi}$ yields at forward rapidity ($1.2<|y|<2.2$) $\text{Au}+\text{Au}$...
The PHENIX experiment presents results from the Relativistic Heavy Ion Collider 2005 run with polarized proton collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$, for inclusive ${\ensuremath{\pi}}^{0}$ production midrapidity. Unpolarized cross section are given transverse momenta ${p}_{T}=0.5$ to $20\text{ }\mathrm{GeV}/c$, extending range of published data both lower and higher ${p}_{T}$. is described well ${p}_{T}<1\text{ }\mathrm{GeV}/c$ by an exponential in ${p}_{T}$, and,...
J/psi production in p+p collisions at square root s=200 GeV has been measured by the PHENIX experiment BNL Relativistic Heavy Ion Collider over a rapidity range of -2.2<y<2.2 and transverse momentum 0<pT<9 GeV/c. The size present data set allows detailed measurement both pT distributions is sufficient to constrain models. total cross section times branching ratio Bll sigma pp J/psi=178+/-3stat+/-53sys+/-18norm nb.
Back-to-back hadron pair yields in d+Au and p+p collisions at sqrt(s_NN)=200 GeV were measured with the PHENIX detector Relativistic Heavy Ion Collider. Rapidity separated pairs detected trigger pseudorapidity |eta|<0.35 associated forward rapidity (deuteron direction, 3.0<eta<3.8). Pairs also both hadrons rapidity; this case yield of back-to-back small impact parameters is observed to be suppressed by a factor 10 relative collisions. The kinematics these expected probe partons Au nucleus...
Yields for J/psi production in Cu+Cu collisions at sqrt s_NN=200 GeV have been measured over the rapidity range |y|<2.2 and compared with results p+p Au+Au same energy. The data offer greatly improved precision existing small to intermediate numbers of participants, where quark-gluon plasma transition threshold is predicted lie. Cold nuclear matter estimates based on ad hoc fits d+Au describe up N_part approximately 50, corresponding a Bjorken energy density least 1.5 GeV/fm(3).
We have measured the azimuthal anisotropy of pi0's for 1 < pT 18 GeV/c Au+Au collisions at sqrt s_NN = 200 GeV. The observed shows a gradual decrease in 3 7 - 10 GeV/c, but remains positive beyond GeV/c. magnitude this is under-predicted, up to least by current perturbative QCD (pQCD) energy-loss model calculations. An estimate increase expected from initial-geometry modification due gluon saturation effects and fluctuations insufficient account discrepancy. Calculations which implement path...
The PHENIX experiment presents results from the RHIC 2006 run with polarized $p+p$ collisions at $\sqrt{s}=62.4\text{ }\text{ }\mathrm{GeV}$, for inclusive ${\ensuremath{\pi}}^{0}$ production midrapidity. Unpolarized cross section are measured transverse momenta ${p}_{T}=0.5$ to $7\text{ }\mathrm{GeV}/c$. Next-to-leading order perturbative quantum chromodynamics calculations compared data, and while consistent measurements, next-to-leading logarithmic corrections improve agreement. Double...
Differential measurements of the elliptic (v_2) and hexadecapole (v_4) Fourier flow coefficients are reported for charged hadrons as a function transverse momentum (p_T) collision centrality or number participant nucleons (N_part) Au+Au collisions at sqrt(s_NN)=200 GeV. The v_{2,4} pseudorapidity |\eta|<=0.35 obtained with four separate reaction plane detectors positioned in range 1.0<|\eta|<3.9 show good agreement, indicating absence significant \eta-dependent nonflow perturbations. Sizable...
The PHENIX experiment has measured electrons and positrons at midrapidity from the decays of hadrons containing charm bottom quarks produced in d+Au p+p collisions sqrt(s_NN)=200 GeV Relativistic Heavy Ion Collider, transverse-momentum range 0.85 < pT 8.5 GeV/c. In central collisions, nuclear modification factor R_dA 1.5 5 GeV/c displays evidence enhancement these electrons, relative to those shows that mass-dependent Cronin observed RHIC extends heavy-D-meson family. A comparison with...
High-energy proton- and deuteron-nucleus collisions provide an excellent tool for studying a wide array of physics effects, including modifications parton distribution functions in nuclei, gluon saturation, color neutralization hadronization nuclear environment, among others. All these effects are expected to have significant dependence on the size target impact parameter collision, also known as collision centrality. In this article, we detail method determining centrality classes p(d)+A...
We present measured $J/\ensuremath{\psi}$ production rates in $d+\text{Au}$ collisions at $\sqrt{{s}_{{}_{NN}}}=200$ GeV over broad ranges of transverse momentum (${p}_{T}=0$--14 GeV/$c$) and rapidity ($\ensuremath{-}2.2<y<2.2$). construct the nuclear-modification factor ${R}_{d\mathrm{Au}}$ for these kinematics as a function collision centrality (related to impact parameter $d+\mathrm{Au}$ collision). find that modification is largest with small parameters observe suppression...
We report the measurement of transverse momentum dependence inclusive $J/\ensuremath{\psi}$ polarization in $p+p$ collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$ performed by PHENIX Experiment Relativistic Heavy Ion Collider. The is studied helicity, Gottfried-Jackson, and Collins-Soper frames for ${p}_{T}<5\text{ }\mathrm{GeV}/c$ $|y|<0.35$. helicity Gottfried-Jackson consistent with zero all momenta, a slight (1.8 sigma) trend towards longitudinal momenta above $2\text{...
The differential cross section for the production of direct photons in $p+p$ collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$ midrapidity was measured PHENIX detector Relativistic Heavy Ion Collider. Inclusive were transverse momentum range from $5.5--25\text{ }\mathrm{GeV}/c$, extending beyond previous measurements. Event structure studied with an isolation criterion. Next-to-leading-order perturbative-quantum-chromodynamics calculations give a good description spectrum. When is...
The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured open heavy-flavor production in minimum bias Au$+$Au collisions $\sqrt{s_{_{NN}}}=200$ GeV via yields of electrons from semileptonic decays charm and bottom hadrons. Previous electron measurements indicated substantial modification momentum distribution parent heavy quarks due to quark-gluon plasma created these collisions. For first time, using silicon vertex detector measure precision displaced tracking, relative...
Background: Heavy-flavor production in $p$ + collisions is a good test of perturbative-quantum-chromodynamics (pQCD) calculations. Modification heavy-flavor heavy-ion relative to binary-collision scaling from results, quantified with the nuclear-modification factor (${R}_{AA}$), provides information on both cold- and hot-nuclear-matter effects. Midrapidity ${R}_{AA}$ measurements at Relativistic Heavy Ion Collider have challenged parton-energy-loss models resulted upper limits...
The PHENIX experiment reports systematic measurements at the Relativistic Heavy Ion Collider of ϕ-meson production in asymmetric Cu+Au collisions sNN=200GeV and U+U sNN=193GeV. Measurements were performed via ϕ→K+K− decay channel midrapidity |η|<0.35. Features measured Cu+Cu, Cu+Au, Au+Au, found to not depend on collision geometry, which was expected because yields are averaged over azimuthal angle follow scaling with nuclear-overlap size. elliptic flow ϕ meson scales...
We present measurements of the J/psi invariant yields in sqrt(s_NN)=39 and 62.4 GeV Au+Au collisions at forward rapidity (1.2<|y|<2.2). Invariant are presented as a function both collision centrality transverse momentum. Nuclear modifications obtained for central relative to peripheral (R_CP) various selections scaled p+p cross sections from other (R_AA). The observed suppression patterns 39 quite similar those previously measured 200 GeV. This presents challenge theoretical models that...
Charged-pion-interferometry measurements were made with respect to the second- and third-order event plane for $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{NN}}=200\text{ }\mathrm{GeV}$. A strong azimuthal-angle dependence of extracted Gaussian-source radii was observed both planes. The results second-order indicate that initial eccentricity is reduced during medium evolution, which consistent previous results. In contrast, triangular shape significantly potentially reversed by end...
The cross section and transverse single-spin asymmetries of ${\ensuremath{\mu}}^{\ensuremath{-}}$ ${\ensuremath{\mu}}^{+}$ from open heavy-flavor decays in polarized $p+p$ collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$ were measured by the PHENIX experiment during 2012 Relativistic Heavy Ion Collider. Because production is dominated gluon-gluon interactions }\mathrm{GeV}$, these measurements offer a unique opportunity to obtain information on trigluon correlation functions. are...
The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured open-heavy-flavor production in $\mathrm{Cu}+\mathrm{Cu}$ collisions $\sqrt{{s}_{NN}}=200$ GeV through measurement of electrons midrapidity that originate from semileptonic decays charm and bottom hadrons. In peripheral an enhanced is observed relative to $p+p$ scaled by number binary collisions. transverse momentum range 1 5 GeV/$c$ nuclear modification factor ${R}_{AA}\ensuremath{\sim}1.4$. As system size...
We have measured the cross section and single-spin asymmetries from forward ${W}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\nu}$ production in longitudinally polarized $p+p$ collisions at $\sqrt{s}=510\text{ }\text{ }\mathrm{GeV}$ using PHENIX detector Relativistic Heavy Ion Collider. The sections are consistent with previous measurements this collision energy, while most backward longitudinal single spin provide new...
Production of $π^0$ and $η$ mesons has been measured at midrapidity in Cu$+$Au collisions $\sqrt{s_{_{NN}}}$=200 GeV. Measurements were performed $π^0(η)\rightarrowγγ$ decay channel the 1(2)-20 GeV/$c$ transverse momentum range. A strong suppression is observed for meson production high central relative to $p$$+$$p$ results scaled by number nucleon-nucleon collisions. In similar Au$+$Au with comparable nuclear overlap. The $η/π^0$ ratio as a function consistent $m_T$-scaling parameterization...