H. J. Crawford
A5017561360- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- Nuclear reactor physics and engineering
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Stochastic processes and statistical mechanics
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- Radiation Therapy and Dosimetry
- Cold Atom Physics and Bose-Einstein Condensates
- Fusion materials and technologies
- Laser-induced spectroscopy and plasma
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Markov Chains and Monte Carlo Methods
- Statistical Methods and Bayesian Inference
- Cosmology and Gravitation Theories
- Solar and Space Plasma Dynamics
- Statistical Mechanics and Entropy
- Theoretical and Computational Physics
- Nuclear Materials and Properties
- Ion-surface interactions and analysis
University of California, Berkeley
2015-2024
Abilene Christian University
2019-2023
University of California, Davis
1987-2023
AGH University of Krakow
2013-2018
Lawrence Berkeley National Laboratory
1978-2013
University of the Basque Country
2011
Ikerbasque
2011
University of Birmingham
2007
Simon Fraser University
2006
The University of Tokyo
1994
Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au p+p collisions at sqrt[s(NN)]=200 GeV. The small-angle observed all centralities of are characteristic hard-scattering processes previously high-energy collisions. A strong back-to-back correlation exists peripheral Au+Au. In contrast, the reduced considerably most central collisions, indicating substantial interaction as hard-scattered partons or...
Inclusive transverse momentum distributions of charged hadrons within 0.2<p(T)<6.0 GeV/c have been measured over a broad range centrality for Au+Au collisions at sqrt[s(NN)]=130 GeV. Hadron yields are suppressed high p(T) in central relative to peripheral and nucleon-nucleon reference scaled collision geometry. Peripheral not the reference. The suppression varies continuously intermediate centralities. results indicate significant nuclear medium effects on high-p(T) hadron production...
Charged hadrons in [EQUATION: SEE TEXT] associated with particles of are reconstructed pp and Au+Au collisions at sqrt[sNN]=200 GeV. The multiplicity p magnitude sum found to increase from central collisions. distributions, while similar shape on the nearside, significantly softened awayside relative not much harder than that inclusive hadrons. results, consistent jet quenching, suggest fragments approach equilibration medium traversed.
We report the beam energy (sqrt[sNN]=7.7-200 GeV) and collision centrality dependence of mean (M), standard deviation (σ), skewness (S), kurtosis (κ) net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by STAR experiment at midrapidity (|y|<0.5) within transverse momentum range 0.4<pT<0.8 GeV/c first phase Beam Energy Scan program Relativistic Heavy Ion Collider. These important for understanding quantum chromodynamic diagram. products moments, Sσ κσ2,...
The STAR collaboration at the BNL Relativistic Heavy-Ion Collider (RHIC) reports measurements of inclusive yield nonphotonic electrons, which arise dominantly from semileptonic decays heavy flavor mesons, over a broad range transverse momenta ($1.2<{p}_{T}<10\text{ }\text{ }\mathrm{GeV}/c$) in $p+p$, $d+\mathrm{Au}$, and $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{\mathrm{NN}}}=200\text{ }\mathrm{GeV}$. electron exhibits an unexpectedly large suppression central high ${p}_{T}$,...
Parity ($\mathcal{P}$)-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted lead charge separation quarks along orbital momentum system in noncentral To study this effect, we investigate a three-particle mixed-harmonics azimuthal correlator which is $\mathcal{P}$-even observable, but directly sensitive charge-separation effect. We report measurements observable using STAR...
We report the first measurements of kurtosis (\kappa), skewness (S) and variance (\sigma^2) net-proton multiplicity (N_p - N_pbar) distributions at midrapidity for Au+Au collisions \sqrt(s_NN) = 19.6, 62.4, 200 GeV corresponding to baryon chemical potentials (\mu_B) between 20 MeV. Our products \kappa \sigma^2 S \sigma, which can be related theoretical calculations sensitive number susceptibilities long range correlations, are constant as functions collision centrality. compare these with...
We report the first measurements of moments -- mean ($M$), variance ($\sigma^{2}$), skewness ($S$) and kurtosis ($\kappa$) net-charge multiplicity distributions at mid-rapidity in Au+Au collisions seven energies, ranging from $\sqrt {{s_{\rm NN}}}$= 7.7 to 200 GeV, as a part Beam Energy Scan program RHIC. The are related thermodynamic susceptibilities net-charge, sensitive proximity QCD critical point. compare products moments, $\sigma^{2}/M$, $S\sigma$ $\kappa\sigma^{2}$ with expectations...
Nuclear collisions recreate conditions in the universe microseconds after Big Bang. Only a very small fraction of emitted fragments are light nuclei, but these states fundamental interest. We report observation antihypertritons - composed an antiproton, antineutron, and antilambda hyperon produced by colliding gold nuclei at high energy. Our analysis yields 70 +- 17 157 30 hypertritons. The measured hypertriton (antihypertriton) helium3 (antihelium3) similar, suggesting equilibrium...
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 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...
Elliptic flow holds much promise for studying the early-time thermalization attained in ultrarelativistic nuclear collisions. Flow measurements also provide a means of distinguishing between hydrodynamic models and calculations which approach low density (dilute gas) limit. Among effects that can complicate interpretation elliptic are azimuthal correlations unrelated to reaction plane (non-flow correlations). Using data Au + collisions at sqrt{s_{NN}} = 130 GeV from STAR TPC, it is found...
We report first results on elliptic flow of identified particles at midrapidity in $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{\mathrm{NN}}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}130\mathrm{GeV}$ using the STAR TPC RHIC. The as a function transverse momentum and centrality differs significantly for different masses. This dependence can be accounted hydrodynamic models, indicating that system created shows behavior consistent with collective hydrodynamical flow. fit to data...
Measurements of the production forward high-energy ${\ensuremath{\pi}}^{0}$ mesons from transversely polarized proton collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$ are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. analyzing power small ${x}_{F}$ below about 0.3, and becomes positive large higher ${x}_{F}$, similar to trend in data $\sqrt{s}\ensuremath{\le}20\text{ }\mathrm{GeV}$. qualitative agreement model...
The STAR Collaboration at the Relativistic Heavy Ion Collider reports measurements of azimuthal correlations high transverse momentum (pT) charged hadrons in Au+Au collisions higher pT than reported previously. As is increased, a narrow, back-to-back peak emerges above decreasing background, providing clear dijet signal for all collision centralities studied. Using these correlations, we perform systematic study production and suppression nuclear collisions, new constraints on mechanisms...
Midrapidity open charm spectra from direct reconstruction of ${D}^{0}(\overline{{D}^{0}})\ensuremath{\rightarrow}{K}^{\ensuremath{\mp}}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ in $d+\mathrm{A}\mathrm{u}$ collisions and indirect electron-positron measurements via semileptonic decays $p+p$ at $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$ are reported. The ${D}^{0}(\overline{{D}^{0}})$ spectrum covers a transverse momentum (${p}_{T}$) range $0.1<{p}_{T}<3\text{...
Measurements of two-particle correlations on angular difference variables ${\ensuremath{\eta}}_{1}\ensuremath{-}{\ensuremath{\eta}}_{2}$ (pseudorapidity) and ${\ensuremath{\phi}}_{1}\ensuremath{-}{\ensuremath{\phi}}_{2}$ (azimuth) are presented for all primary charged hadrons with transverse momentum $0.15\ensuremath{\le}{p}_{t}\ensuremath{\le}2$ GeV/$c$ $|\ensuremath{\eta}|\ensuremath{\le}1.3$ from Au-Au collisions at $\sqrt{{s}_{\mathit{NN}}}=130$ GeV. Large-amplitude observed over a broad...
We present the scaling properties of Lambda, Xi, and Omega in midrapidity Au+Au collisions at Brookhaven National Laboratory Relativistic Heavy Ion Collider sqrt[s_{NN}]=200 GeV. The yield multistrange baryons per participant nucleon increases from peripheral to central more rapidly than that indicating an increase strange-quark density matter produced. strange phase-space occupancy factor gamma_{s} approaches unity for most collisions. Moreover, nuclear modification factors p, Xi are...
We report on the first measurement of elliptic flow v2(pT) multistrange baryons Xi- +Xi+ and Omega- + Omega+ in heavy-ion collisions. In minimum-bias Au+Au collisions at square root s(NN)=200 GeV, a significant amount flow, comparable to other nonstrange baryons, is observed for which are expected be particularly sensitive dynamics partonic stage The pT dependence v2 confirms number constituent quark scaling previously lighter hadrons. These results support idea that substantial fraction...
The short-lived $K(892){}^{*}$ resonance provides an efficient tool to probe properties of the hot and dense medium produced in relativistic heavy-ion collisions. We report measurements ${K}^{*}$ $\sqrt{{s}_{\mathit{NN}}}=200\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}$ Au+Au $p+p$ collisions reconstructed via its hadronic decay channels $K(892){}^{*0}\ensuremath{\rightarrow}K\ensuremath{\pi}$...
Analysis of the factorizability several sets fragment-production cross sections has been performed for $^{12}\mathrm{C}$, $^{16}\mathrm{O}$, $^{18}\mathrm{O}$, and $^{56}\mathrm{Fe}$ projectiles in 1 to 2 GeV/nucleon energy region targets ranging from Be U. The results this analysis are considered terms geometrical concepts. No evidence is found that there any dependence fragmentation channel upon impact parameter. It as well projectile target factors much less than predicted by...
We report measurements of charmed-hadron $({D}^{0},{D}^{*})$ production cross sections at midrapidity in $p+p$ collisions a center-of-mass energy 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via hadronic decays ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$, ${D}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}$ and their charge conjugates,...
We report the first measurement of elliptic anisotropy (v_{2}) charm meson D^{0} at midrapidity (|y|<1) in Au+Au collisions sqrt[s_{NN}]=200 GeV. The was conducted by STAR experiment RHIC utilizing a new high-resolution silicon tracker. measured v_{2} 0%-80% centrality can be described viscous hydrodynamic calculation for transverse momentum (p_{T}) less than 4 GeV/c. as function kinetic energy (m_{T}-m_{0}, where m_{T}=sqrt[p_{T}^{2}+m_{0}^{2}]) is consistent with that light mesons 10%-40%...
We report measurements of the third harmonic coefficient azimuthal anisotropy, ${v}_{3}$, known as triangular flow. The analysis is for charged particles in Au+Au collisions at $\sqrt{{s}_{\mathit{NN}}}=200$ GeV, based on data from STAR experiment BNL Relativistic Heavy Ion Collider. Two-particle correlations a function their pseudorapidity separation are fit with narrow and wide Gaussians. Measurements flow extracted Gaussian, two-particle cumulants gap, also event plane methods large gap...