A5053596896- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Nuclear reactor physics and engineering
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Nuclear physics research studies
- Stochastic processes and statistical mechanics
- Superconducting Materials and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Markov Chains and Monte Carlo Methods
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Theoretical and Computational Physics
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Statistical Methods and Bayesian Inference
- Atomic and Subatomic Physics Research
- Dark Matter and Cosmic Phenomena
- Ion-surface interactions and analysis
- Laser-Plasma Interactions and Diagnostics
- Photocathodes and Microchannel Plates
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Cold Atom Physics and Bose-Einstein Condensates
Brookhaven National Laboratory
2016-2025
University of California, Riverside
2012-2024
Williams (United States)
2024
Eötvös Loránd University
2024
William & Mary
2024
Abilene Christian University
2018-2023
PHENIX laboratory
2006-2023
Banaras Hindu University
2016-2023
Charles University
2016-2023
Augustana University
2016-2023
The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with $0.3<{p}_{T}<9\text{ }\text{ }\mathrm{GeV}/c$ midrapidity ($|y|<0.35$) from heavy-flavor (charm and bottom) decays in $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{\mathrm{NN}}}=200\text{ }\mathrm{GeV}$. nuclear modification factor ${R}_{\mathrm{AA}}$ relative to $p+p$ shows a strong suppression central collisions, indicating substantial energy loss of heavy quarks medium produced RHIC...
We present measurements of bulk properties the matter produced in Au+Au collisions at $\sqrt{s_{NN}}=$ 7.7, 11.5, 19.6, 27, and 39 GeV using identified hadrons ($\pi^\pm$, $K^\pm$, $p$ $\bar{p}$) from STAR experiment Beam Energy Scan (BES) Program Relativistic Heavy Ion Collider (RHIC). Midrapidity ($|y|<$0.1) results for multiplicity densities $dN/dy$, average transverse momenta $\langle p_T \rangle$ particle ratios are presented. The chemical kinetic freeze-out dynamics these energies...
The production of low mass e+e- pairs for m_{e+e-} < 300 MeV/c^2 and 1 p_T <5 GeV/c is measured in p+p Au+Au collisions at sqrt(s_NN)=200 GeV. Enhanced yield above hadronic sources observed. Treating the excess as internal conversions, invariant direct photons deduced. In central collisions, photon over exponential transverse momentum, with inverse slope T = 221 +/- 19 (stat) (syst) MeV. Hydrodynamical models initial temperatures ranging from 300--600 MeV times ~ 0.6 - 0.15 fm/c after...
The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC)has measured $J/\ensuremath{\psi}$ production for rapidities $\ensuremath{-}2.2<y<2.2$ in $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$. invariant yield and nuclear modification factor ${R}_{AA}$ as a function of centrality,transverse momentum, rapidity are reported. A suppression relative to binary collision scaling proton-protonreaction yields is observed. Models which describe...
Differential measurements of elliptic flow (${v}_{2}$) for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ collisions at $\sqrt{{s}_{\mathrm{NN}}}=200\text{ }\text{ }\mathrm{GeV}$ are used to test validate predictions from perfect fluid hydrodynamics scaling ${v}_{2}$ with eccentricity, system size, transverse kinetic energy (${\mathrm{KE}}_{T}$). For ${\mathrm{KE}}_{T}\ensuremath{\equiv}{m}_{T}\ensuremath{-}m$ up $\ensuremath{\sim}1\text{ the is compatible hydrodynamic expansion a...
Azimuthal angle ($\ensuremath{\Delta}\ensuremath{\phi}$) correlations are presented for a broad range of transverse momentum ($0.4<{p}_{T}<10$ GeV/$c$) and centrality (0--92%) selections charged hadrons from dijets in Au+Au collisions at $\sqrt{{s}_{\mathit{NN}}}=200$ GeV. With increasing ${p}_{T}$, the away-side $\ensuremath{\Delta}\ensuremath{\phi}$ distribution evolves relatively flat shape to concave shape, then convex shape. Comparisons with $p+p$ data suggest that can be divided into...
For Au + collisions at 200 GeV, we measure neutral pion production with good statistics for transverse momentum, pT, up to 20 GeV/c. A fivefold suppression is found, which essentially constant 5 < pT Experimental uncertainties are small enough constrain any model-dependent parametrization the transport coefficient of medium, e.g., q in parton quenching model. The spectral shape similar all collision classes, and does not saturate collisions.
PHENIX has measured the e^+e^- pair continuum in sqrt(s_NN)=200 GeV Au+Au and p+p collisions over a wide range of mass transverse momenta. The yield is compared to expectations from hadronic sources, based on measurements. In intermediate region, between masses phi J/psi meson, consistent with correlated c^bar-c production, though other mechanisms are not ruled out. low region (below phi) inclusive spectrum well described by known contributions light meson decays. contrast, minimum bias this...
Global polarization of $\Lambda$ hyperons has been measured to be the order a few tenths percent in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV, with no significant difference between and $\bar{\Lambda}$. These new results reveal collision energy dependence global together previously observed 7.7 -- 62.4 GeV indicate noticeable vorticity medium created non-central heavy-ion highest RHIC energy. The signal is rough quantitative agreement theoretical predictions from hydrodynamic model...
Transverse momentum spectra of electrons (${p}_{T}^{e}$) from semileptonic weak decays heavy-flavor mesons in the range $0.3<{p}_{T}^{e}<9.0$ GeV/$c$ have been measured at midrapidity ($|y|<0.35$) by PHENIX experiment Relativistic Heavy Ion Collider $p+p$ and $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{\mathrm{NN}}}=200$ GeV. In addition, azimuthal anisotropy parameter ${v}_{2}$ has for $0.3<{p}_{T}^{e}<5.0$ collisions. The substantial modification ${p}_{T}^{e}$ compared with as well...
Rapidity-odd directed flow (v1) measurements for charged pions, protons, and antiprotons near midrapidity (y=0) are reported in sNN=7.7, 11.5, 19.6, 27, 39, 62.4, 200 GeV Au+Au collisions as recorded by the STAR detector at Relativistic Heavy Ion Collider. At intermediate impact parameters, proton net-proton slope parameter dv1/dy|y=0 shows a minimum between 11.5 19.6 GeV. In addition, changes sign twice 7.7 39 The results qualitatively resemble predictions of hydrodynamic model with...
The PHENIX experiment at the Relativistic Heavy Ion Collider has measured invariant differential cross section for production of ${K}_{S}^{0}$, $\ensuremath{\omega}$, ${\ensuremath{\eta}}^{\ensuremath{'}}$, and $\ensuremath{\phi}$ mesons in $p+p$ collisions $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$. Measurements $\ensuremath{\omega}$ different decay channels give consistent results. New results are agreement with previously published data extend ${p}_{T}$ coverage. spectral shapes all...
We report the first measurement of charmed-hadron (D(0)) production via hadronic decay channel (D(0) → K(-) + π(+)) in Au+Au collisions at sqrt[s(NN)] = 200 GeV with STAR experiment. The charm cross section per nucleon-nucleon collision midrapidity scales number binary collisions, N(bin), from p+p to central collisions. D(0) meson yields Au are strongly suppressed compared those scaled by for transverse momenta p(T) > 3 GeV/c, demonstrating significant energy loss quarks hot and dense...
Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local manifest themselves as charge separation along the magnetic field axis via chiral effect. experimental observation of previously reported for collisions at top RHIC energies. In this Letter, we present results beam-energy dependence correlations $\mathrm{Au}+\mathrm{Au}$ midrapidity center-of-mass energies 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from...
The Λ (Λ[over ¯]) hyperon polarization along the beam direction has been measured in Au+Au collisions at sqrt[s_{NN}]=200 GeV, for first time heavy-ion collisions. dependence on hyperons' emission angle relative to elliptic flow plane exhibits a second harmonic sine modulation, indicating quadrupole pattern of vorticity component direction, expected due flow. is found increase more peripheral collisions, and shows no strong transverse momentum (p_{T}) p_{T} greater than 1 GeV/c. magnitude...
Non-monotonic variation with collision energy ($\sqrt{s_{\rm NN}}$) of the moments net-baryon number distribution in heavy-ion collisions, related to correlation length and susceptibilities system, is suggested as a signature for Quantum Chromodynamics (QCD) critical point. We report first evidence non-monotonic kurtosis times variance net-proton (proxy number) function \rootsnn 3.1$\sigma$ significance, head-on (central) gold-on-gold (Au+Au) collisions measured using STAR detector at RHIC....
The chiral magnetic effect (CME) is predicted to occur as a consequence of local violation $\mathcal{P}$ and $\mathcal{C}P$ symmetries the strong interaction amidst electromagnetic field generated in relativistic heavy-ion collisions. Experimental manifestation CME involves separation positively negatively charged hadrons along direction field. Previous measurements CME-sensitive charge-separation observables remain inconclusive because large background contributions. To better control...
The Breit-Wheeler process which produces matter and anti-matter from photon collisions is investigated experimentally through the observation of 6085 exclusive electron-positron pairs in ultra-peripheral Au+Au at $\sqrt{s_{_{NN}}}=200$ GeV. measurements reveal a large fourth-order angular modulation $\cos{4\Delta\phi}=(16.8\pm2.5)\%$ smooth invariant mass distribution absent vector mesons ($\phi$, $\omega$ $\rho$) experimental limit $\le 0.2\%$ observed yields. differential cross section as...
We report a systematic measurement of cumulants, $C_{n}$, for net-proton, proton and antiproton multiplicity distributions, correlation functions, $\kappa_n$, distributions up to the fourth order in Au+Au collisions at $\sqrt{s_{\mathrm {NN}}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4 200 GeV. The $C_{n}$ $\kappa_n$ are presented as function collision energy, centrality kinematic acceptance rapidity, $y$, transverse momentum, $p_{T}$. data were taken during first phase Beam Energy Scan...
The strong force, as one of the four fundamental forces at work in universe, governs interactions quarks and gluons, binds together atomic nucleus. Notwithstanding decades progress since Yukawa first developed a description force between nucleons terms meson exchange, full understanding interaction remains major challenge modern science. One remaining difficulty arises from non-perturbative nature which leads to phenomenon quark confinement distance scales on order size proton. Here we show...
The deconfined quark-gluon plasma (QGP) created in relativistic heavy-ion collisions enables the exploration of fundamental properties matter under extreme conditions. Noncentral can produce strong magnetic fields on order <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mn>10</a:mn><a:mn>18</a:mn></a:msup><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi mathvariant="normal">G</a:mi></a:math>, which offers a probe into electrical conductivity QGP. In particular,...
In heavy-ion collision experiments, the global collectivity of final-state particles can be quantified by anisotropic flow coefficients (𝑣𝑛). The first-order coefficient, also referred to as directed (𝑣1), describes collective sideward motion produced and nuclear fragments in collisions. It carries information on very early stage collision, especially at large pseudorapidity (𝜂), where it is believed generated during passage time. Directed therefore probes onset bulk dynamics thermalization,...
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,...
Transverse momentum distributions and yields for ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}^{\ifmmode\pm\else\textpm\fi{}}$, $p$, $\mathrm{p\ifmmode \bar{}\else \={}\fi{}}$ in $p+p$ collisions at $\sqrt{s}$ $=$ 200 62.4 GeV midrapidity are measured by the PHENIX experiment Relativistic Heavy Ion Collider (RHIC). These data provide important baseline spectra comparisons with identified particle heavy ion RHIC. We present inverse slope parameter ${T}_{\mathrm{inv}}$, mean...
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,...