A5024355385- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Muon and positron interactions and applications
- Particle Detector Development and Performance
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Nuclear physics research studies
- Nuclear reactor physics and engineering
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Atomic and Molecular Physics
- Radiation Detection and Scintillator Technologies
- Advanced NMR Techniques and Applications
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Semiconductor materials and devices
- Fusion materials and technologies
- Silicon Carbide Semiconductor Technologies
- Statistical Methods and Bayesian Inference
- Radiation Effects in Electronics
- Astrophysics and Cosmic Phenomena
- Ammonia Synthesis and Nitrogen Reduction
- Dark Matter and Cosmic Phenomena
- Pediatric Urology and Nephrology Studies
Kyoto University
2010-2024
High Energy Accelerator Research Organization
2015-2024
RIKEN Nishina Center
2012-2024
Japan Proton Accelerator Research Complex
2021-2023
Charles University
2010-2023
PHENIX laboratory
2010-2023
Banaras Hindu University
2010-2023
Augustana University
2016-2023
Abilene Christian University
2018-2023
Bhabha Atomic Research Centre
2023
Transverse momentum spectra of charged hadrons with p(T)<8 GeV/c and neutral pions p(T)<10 have been measured at midrapidity by the PHENIX experiment BNL RHIC in d+Au collisions sqrt[s(NN)]=200 GeV. The yields are compared to those p+p same sqrt[s(NN)] scaled up number underlying nucleon-nucleon d+Au. yield ratio does not show suppression observed central Au+Au RHIC. Instead, there is a small enhancement high particles.
Flow coefficients v_n for n = 2, 3, 4, characterizing the anisotropic collective flow in Au+Au collisions at sqrt(s_NN) 200 GeV, are measured relative to event planes \Psi_n determined large rapidity. We report as a function of transverse momentum and collision centrality, study correlations among different order n. The well described by hydrodynamic models which employ Glauber Monte Carlo initial state geometry with fluctuations, providing additional constraining power on interplay between...
The PHENIX collaboration at the Relativistic Heavy Ion Collider (RHIC) reports measurements of azimuthal dihadron correlations near midrapidity in $d$$+$Au collisions $\sqrt{s_{_{NN}}}$=200 GeV. These complement recent analyses by experiments Large Hadron (LHC) involving central $p$$+$Pb $\sqrt{s_{_{NN}}}$=5.02 TeV, which have indicated strong anisotropic long-range angular distributions hadron pairs. origin these anisotropies is currently unknown. Various competing explanations include...
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 ${p}_{T}>6\text{ reduced interpreted terms path-length dependence...
This paper introduces a new approach to measure the muon magnetic moment anomaly |$a_{\mu} = (g-2)/2$| and electric dipole (EDM) |$d_{\mu}$| at J-PARC facility. The goal of our experiment is |$a_{\mu}$| using an independent method with factor 10 lower momentum, 20 smaller diameter storage-ring solenoid compared previous ongoing |$g-2$| experiments unprecedented quality storage field. Additional significant differences from present experimental include 1000 transverse emittance beam...
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,...
The invariant mass spectra of e+e- pairs produced in 12 GeV proton-induced nuclear reactions are measured at the KEK Proton Synchrotron. On low-mass side meson peak, a significant enhancement over known hadronic sources has been observed. spectra, including excess, well reproduced by model that takes into account density dependence vector modification, as theoretically predicted.
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.
The dependence of transverse momentum spectra neutral pions and $\ensuremath{\eta}$ mesons with ${p}_{T}<16\text{ }\text{ }\mathrm{GeV}/c$ ${p}_{T}<12\text{ }\mathrm{GeV}/c$, respectively, on the centrality collision has been measured at midrapidity by PHENIX experiment BNL Relativistic Heavy Ion Collider (RHIC) in $d+\mathrm{Au}$ collisions $\sqrt{{s}_{NN}}=200\text{ }\mathrm{GeV}$. yields are compared to those $p+p$ same $\sqrt{{s}_{NN}}$ scaled number underlying nucleon-nucleon...
Invariant mass spectra of e(+) e(-) pairs have been measured in 12 GeV p + A reactions to detect possible in-medium modification vector mesons. Copper and carbon targets are used study the nuclear-size dependence invariant distributions. significant excess on low-mass side phi meson peak is observed low betagamma(= beta/square root(1-beta(2))) region mesons (betagamma < 1.25) with copper targets. However, high betagamma > 1.25), spectral shapes well described by Breit-Wigner shape when...
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...
We present results for three charmonia states (${\ensuremath{\psi}}^{\ensuremath{'}}$, ${\ensuremath{\chi}}_{c}$, and $J/\ensuremath{\psi}$) in $d+\mathrm{Au}$ collisions at $|y|<0.35$ $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$. find that the modification of ${\ensuremath{\psi}}^{\ensuremath{'}}$ yield relative to $J/\ensuremath{\psi}$ scales approximately with charged particle multiplicity midrapidity across $p+A$, $d+\mathrm{Au}$, $A+A$ from Super Proton Synchrotron Relativistic...
Cross sections for midrapidity production of direct photons in p+p collisions at the Relativistic Heavy Ion Collider (RHIC) are reported transverse momenta 3 < pT 16 GeV/c. Next-to-leading order perturbative QCD (pQCD) describes data well >5 GeV/c, where uncertainties measurement and theory comparable. We also report on effect requiring to be isolated from parton jet energy. The observed fraction is described by pQCD >7
$J/\ensuremath{\psi}$ production in $d+\mathrm{Au}$ and $p+p$ collisions at $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$ has been measured by the PHENIX experiment rapidities $\ensuremath{-}2.2<y<+2.4$. The cross sections nuclear dependence of versus rapidity, transverse momentum, centrality are obtained compared to lower energy $p+A$ results theoretical models. observed is found be modest, suggesting that absorption final state weak shadowing gluon distributions small consistent with...
Differential elliptic flow (${v}_{2}$) for $\ensuremath{\phi}$ mesons and (anti)deuterons $(\overline{d})d$ is measured $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$. The ${v}_{2}$ follows the trend of lighter ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ ${K}^{\ifmmode\pm\else\textpm\fi{}}$ mesons, suggesting that ordinary hadrons interacting with standard hadronic cross sections are not primary driver development. values suggest additive...
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 present the first measurement of photoproduction J/ψ and two-photon production high-mass e+e− pairs in electromagnetic (or ultra-peripheral) nucleus–nucleus interactions, using Au + data at sNN=200 GeV. The events are tagged with forward neutrons emitted following Coulomb excitation one or both Au⋆ nuclei. event sample consists 28 me+e−>2 GeV/c2 zero like-sign background. measured cross sections midrapidity dσ/dy(J/ψ+Xn,y=0)=76±33(stat)±11(syst) μb...
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...
We report the measurement of direct photons at midrapidity in $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$. The photon signal was extracted for transverse momentum range $4\text{ }\mathrm{GeV}/\phantom{\rule{0ex}{0ex}}c<{p}_{T}<22\text{ }\mathrm{GeV}/c$, using a statistical method to subtract decay from inclusive sample. nuclear modification factor ${R}_{\mathrm{AA}}$ calculated as function ${p}_{T}$ different collision centralities measured $p+p$...
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...
We present inclusive charged hadron elliptic flow (${v}_{2}$) measured over the pseudorapidity range $|\ensuremath{\eta}|<0.35$ in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{\mathit{NN}}}=200$ GeV. Results for ${v}_{2}$ are presented a broad of transverse momentum $({p}_{T}=0.2\text{\ensuremath{-}}8.0$ GeV/$c$) and centrality (0--60%). To study nonflow effects that correlations other than collective flow, as well fluctuations ${v}_{2}$, we compare two different analysis methods: (1)...
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...