A5000256713- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Superconducting Materials and Applications
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Magnetic confinement fusion research
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- Crystallography and Radiation Phenomena
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Data Storage Technologies
- Advancements in Photolithography Techniques
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- Optical Systems and Laser Technology
- Advanced Materials Characterization Techniques
- Photocathodes and Microchannel Plates
- Radiation Detection and Scintillator Technologies
- Scientific Computing and Data Management
- Atomic and Molecular Physics
- Pulsed Power Technology Applications
- Distributed and Parallel Computing Systems
- Integrated Circuits and Semiconductor Failure Analysis
Brookhaven National Laboratory
2009-2025
Stony Brook University
2002-2020
University at Albany, State University of New York
2002-2008
Albany State University
2002-2008
TU Dortmund University
2007
Technical University of Darmstadt
2007
RIKEN BNL Research Center
2002-2007
National Library of Luxembourg
2007
Institute of Engineering Physics
2007
Moscow Engineering Physics Institute
2007
Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation reaction plane. extracted values (v2) show significant sensitivity to both collision centrality and transverse momenta emitted hadrons, suggesting rapid thermalization relatively strong velocity fields. When scaled by eccentricity zone...
Transverse single-spin asymmetries to probe the transverse-spin structure of proton have been measured for neutral pions and nonidentified charged hadrons from polarized proton-proton collisions at midrapidity s=200 GeV. The data cover a transverse momentum (pT) range 1.0–5.0 GeV/c 0.5–5.0 hadrons, Feynman-x value approximately zero. seen in this previously unexplored kinematic region are consistent with zero within errors few percent. In addition, inclusive hadron cross section 0.5<pT<7.0...
The PHENIX experiment has measured midrapidity transverse momentum spectra (0.4<p(T)<4.0 GeV/c) of single electrons as a function centrality in Au+Au collisions at sqrt[s(NN)]=200 GeV. Contributions from photon conversions and Dalitz decays light neutral mesons are by introducing thin (1.7% X0) converter into the acceptance statistically removed. subtracted nonphotonic electron primarily due to semileptonic hadrons containing heavy quarks, mainly charm lower p(T). For all centralities,...
We report the measurement of cumulants ($C_n, n=1\ldots4$) net-charge distributions measured within pseudorapidity ($|\eta|<0.35$) in Au$+$Au collisions at $\sqrt{s_{_{NN}}}=7.7-200$ GeV with PHENIX experiment Relativistic Heavy Ion Collider. The ratios (e.g. $C_1/C_2$, $C_3/C_1$) distributions, which can be related to volume independent susceptibility ratios, are studied as a function centrality and energy. These quantities important understand quantum-chromodynamics phase diagram possible...
In this document the PHENIX collaboration proposes a major upgrade to detector at Relativistic Heavy Ion Collider. This upgrade, sPHENIX, enables an extremely rich jet and beauty quarkonia physics program addressing fundamental questions about nature of strongly coupled quark-gluon plasma (QGP), discovered experimentally RHIC be perfect fluid. The startling dynamics QGP on fluid-like length scales is emergent property quantum chromodynamics (QCD), seemingly implicit in Lagrangian but...
Based on an evaluation of data pion interferometry and particle yields at midrapidity, we propose a universal condition for thermal freeze-out pions in heavy-ion collisions. We show that occurs when the mean free path lambda(f) reaches value about 1 fm, which is much smaller than spatial extent system freeze-out. This critical independent centrality collision beam energy from Alternating Gradient Synchrotron to Relativistic Heavy Ion Collider.
New PHENIX measurements of the anisotropic flow coefficients $v_2\{\Psi_2\}$, $v_3\{\Psi_3\}$, $v_4\{\Psi_4\}$ and $v_4\{\Psi_2\}$ for identified particles ($\pi^{\pm}$, $K^{\pm}$, $p+\bar{p}$) obtained relative to event planes $\Psi_n$ in Au$+$Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV are presented as functions collision centrality particle transverse momenta $p_T$. The $v_n$ show characteristic patterns consistent with hydrodynamical expansion matter produced collisions. For each...
Elliptic flow and two-particle azimuthal correlations of charged hadrons high-p(T) pions (p(T)>1 GeV/c) have been measured close to midrapidity in 158A GeV/c Pb+Au collisions by the CERES experiment. (v(2)) rises linearly with p(T) a value about 10% at 2 GeV/c. Beyond approximately 1.5 GeV/c, slope decreases considerably, possibly indicating saturation v(2) high p(T). Two-pion anisotropies for p(T)>1.2 exceed elliptic values 60% midcentral collisions. These nonflow contributions are...
Bent crystal channeling has been observed with protons and fully stripped gold ions in the Relativistic Heavy Ion Collider (RHIC). Prior to 2003, a bent was installed one ring of RHIC as first stage two collimation system. The efficiency approximately $25%$, less than half original predictions. We show that this is due difference between model real Twiss parameters at location our improved understanding beam halo. Collimation using unsuccessful raised background STAR detector by much factor...
Measurements of anisotropic flow Fourier coefficients (${v}_{n}$) for inclusive charged particles and identified hadrons ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}, {K}^{\ifmmode\pm\else\textpm\fi{}}, p$, $\overline{p}$ produced at midrapidity in $\mathrm{Cu}+\mathrm{Au}$ collisions $\sqrt{{s}_{{}_{\mathit{NN}}}}=200$ GeV are presented. The data were collected 2012 by the PHENIX experiment Relativistic Heavy-Ion Collider (RHIC). particle azimuthal distributions with respect to...
Cooling of beams gold ions using electron bunches accelerated with radio-frequency systems was recently experimentally demonstrated in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. Such an approach is new and opens possibility this technique higher energies than possible electrostatic acceleration beams. The challenges include generation suitable for cooling, delivery required quality to cooling sections without degradation beam angular divergence energy spread,...
We present a measurement of the double longitudinal spin asymmetry in inclusive ${\ensuremath{\pi}}^{0}$ production polarized proton-proton collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$. The data were taken Relativistic Heavy Ion Collider with average beam polarizations 0.27. measurements are first program to study structure proton, using strongly interacting probes, collider energies. is presented for transverse momenta $1--5\text{...
We report the first observations of beam losses due to bound-free pair production at interaction point a heavy-ion collider. This process is expected be major luminosity limit for CERN Large Hadron Collider when it operates with (208)Pb(82+) ions because localized energy deposition by lost may quench superconducting magnet coils. Measurements were performed BNL Relativistic Heavy Ion (RHIC) during operation 100 GeV/nucleon (63)Cu(29+) ions. At RHIC, rate, and magnetic field are low enough so...
The Brookhaven Relativistic Heavy Ion Collider (RHIC) has been providing collisions of polarized protons at a beam energy 100 GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to GeV. However, the intrinsic spin resonances beyond are about factor 2 stronger than those below making it important examine impact these strong on survival and tolerance for vertical orbit distortions. Polarized were first accelerated...
A hollow electron beam has been proposed as an active control tool to remove the halo from high-energy, high-current hadron or ion machines (such High-Luminosity Large Hadron Collider). To study removal rate and assess effect on core, one of two lenses in Relativistic Heavy Ion Collider was changed a Gaussian profile profile. We describe design verification parameters well methods minimize distortions, which can result emittance increase. The alignment with by using backscattered detector...
Two electron lenses ($e$-lenses) have been in operation during the 2015 RHIC physics run as part of a head-on beam-beam compensation scheme. While lattice was chosen to reduce beam-beam-induced resonance-driving terms, reduced tune spread. This has demonstrated for first time. The scheme allows higher parameters and therefore intensities luminosity. In this paper, we detail design considerations verification beam $e$-lenses. Longitudinal transverse alignments with ion beams transfer function...
The Low Energy RHIC electron Cooling (LEReC) project at Brookhaven National Laboratory recently demonstrated for the first time cooling of hadron bunches with radio-frequency (rf) accelerated bunches. LEReC uses a high-voltage photoemission gun stringent requirements beam current, quality, and stability. has photocathode high-power fiber laser, novel cathode production, transport, exchange system. It been that can continually produce high-current quality suitable cooling. We describe...
A high-current high-brightness electron accelerator for low-energy RHIC cooling (LEReC) was successfully commissioned at Brookhaven National Laboratory. The LEReC includes a dc photoemission gun, laser system, photocathode delivery magnets, beam diagnostics, superconducting rf booster cavity, and set of normal conducting cavities to provide enough flexibility tune the in longitudinal phase space. Cooling with nonmagnetized accelerated beams requires corrections obtain small momentum spread...
We present results of a two-pion correlation analysis performed with the $\mathrm{Pb}+\mathrm{Au}$ collision data collected by upgraded CERES experiment in fall 2000. The was done bins reaction centrality and pion azimuthal emission angle respect to plane. source, deduced from data, is slightly elongated direction perpendicular plane, similarly as observed at Brookhaven National Laboratory Alternating Gradient Synchrotron Relativistic Heavy Ion Collider.
Deuteron and gold beams have been accelerated to a collision energy of /spl radic/s = 200 GeV/u in the Relativistic Heavy Ion Collider (RHIC), providing first asymmetric-species collisions this complex. Necessary changes for mode operation include new ramping software asymmetric crossing angle geometries. This paper reviews machine performance, problems encountered their solutions, accomplishments during 16 weeks ramp-up operations.