Refine
Year of publication
Document Type
- Article (469) (remove)
Language
- English (469) (remove)
Has Fulltext
- yes (469)
Is part of the Bibliography
- no (469)
Keywords
- Heavy Ion Experiments (21)
- Hadron-Hadron Scattering (11)
- Hadron-Hadron scattering (experiments) (11)
- LHC (9)
- Heavy-ion collision (6)
- ALICE experiment (4)
- Collective Flow (4)
- Jets (4)
- Quark-Gluon Plasma (4)
- ALICE (3)
- Elastic scattering (3)
- Heavy Ions (3)
- Heavy Quark Production (3)
- Jets and Jet Substructure (3)
- pp collisions (3)
- Beauty production (2)
- Charm physics (2)
- Collectivity (2)
- Correlation (2)
- Diffraction (2)
- Elliptic flow (2)
- Experimental nuclear physics (2)
- Experimental particle physics (2)
- Heavy-ion collisions (2)
- Lepton-Nucleon Scattering (experiments) (2)
- Particle Correlations and Fluctuations (2)
- Particle and resonance production (2)
- Particle correlations and fluctuations (2)
- Pb–Pb collisions (2)
- Polarization (2)
- QCD (2)
- Quarkonium (2)
- RHIC (2)
- Shear viscosity (2)
- Single electrons (2)
- 900 GeV (1)
- ALICE detector (1)
- ALL (1)
- AML (1)
- Anti-nuclei (1)
- Atherosclerosis (1)
- Atmospheric science (1)
- B-slope (1)
- Bayesian inference (1)
- Boosted Jets (1)
- CT-guided interventions (1)
- Caenorhabditis elegans (1)
- Cancer (1)
- Cancer staging (1)
- Cell division (1)
- Cell membranes (1)
- Centrality Class (1)
- Centrality Selection (1)
- Charged-particle multiplicity (1)
- Charm quark spatial diffusion coefficient (1)
- Charmonia (1)
- Checkpoints (1)
- Climate change (1)
- Coalescence (1)
- Cold nuclear matter effects (1)
- Collective Flow, (1)
- Comparison with QCD (1)
- Critical point (1)
- Depolarization (1)
- Deuteron production (1)
- Di-hadron correlations (1)
- Electron-pion identification (1)
- Electroweak interaction (1)
- Entomology (1)
- Femtoscopy (1)
- Fibre/foam sandwich radiator (1)
- First experience with patients (1)
- Flow (1)
- Groomed jet radius (1)
- HBT (1)
- Hadron production (1)
- Hadron-Hadron Scattering Heavy (1)
- Hadron-hadron interactions (1)
- Hadronization (1)
- Hard Scattering (1)
- Heavy Ion Experiment (1)
- Heavy flavor production (1)
- Heavy flavour production (1)
- Heavy ion collisions (1)
- Heavy ions (1)
- Heavy-Ion Collision (1)
- Heavy-flavor decay electron (1)
- Heavy-flavour decay muons (1)
- Heavy-flavour production (1)
- Heavy-ion (1)
- Higher moments (1)
- Inclusive spectra (1)
- Intensity interferometry (1)
- Interference fragmentation function (1)
- Invariant Mass Distribution (1)
- Ionisation energy loss (1)
- J/ψ suppression (1)
- Jet Physics (1)
- Jet Substructure (1)
- Jet substructure (1)
- LNS (1)
- Laser navigation system (1)
- Light (1)
- MLL (1)
- Membrane potential (1)
- Mid-rapidity (1)
- Minimum Bias (1)
- Monte Carlo (1)
- Multi-Parton Interactions (1)
- Multi-strange baryons (1)
- Multi-wire proportional drift chamber (1)
- Multidetector computed tomography (1)
- Multiple parton interactions (1)
- Muscle contraction (1)
- Neoplasms (1)
- Net-charge correlations (1)
- Net-charge fluctuations (1)
- Neural network (1)
- Nonflow (1)
- Nuclear modification factor (1)
- Optogenetics (1)
- PYTHIA (1)
- Particle and Resonance Production (1)
- Pb–Pb (1)
- Phantom study (1)
- Phospholipids (1)
- Phylogenomics (1)
- Plasmid mapping (1)
- Population genetics (1)
- Production Cross Section (1)
- Properties of Hadrons (1)
- Proton-proton collisions (1)
- Proton–proton (1)
- Proton–proton collisions (1)
- Quark Deconfinement (1)
- Quark Gluon Plasma (1)
- Quark Production (1)
- Quark gluon plasma (1)
- Rapidity Range (1)
- Regulatory networks (1)
- Relativistic heavy ion physics (1)
- Relativistic heavy-ion collisions (1)
- Resolution Parameter (1)
- STAR (1)
- Single muons (1)
- SoftDrop (1)
- Spin alignment (1)
- Splitting function (1)
- Systematic Uncertainty (1)
- TR (1)
- Thermal model (1)
- Time Projection Chamber (1)
- Tracking (1)
- Transition radiation detector (1)
- Transverse momentum (1)
- Transversity (1)
- Trigger (1)
- Vector Boson Production (1)
- Xenon-based gas mixture (1)
- abdominal imaging (1)
- acute leukemia (1)
- biogeographic legaciese (1)
- brain-derived neurotrophic factor (1)
- chromosomal translocations (1)
- computer tomography (1)
- cortisol (1)
- dE/dx (1)
- development (1)
- ectosomes (1)
- exosomes (1)
- extracellular vesicles (1)
- forest classification (1)
- forest functional similarity (1)
- guidelines (1)
- heavy ion experiments (1)
- high-pitch (1)
- microbiome (1)
- microparticles (1)
- microvesicles (1)
- minimal information requirements (1)
- p+p collisions (1)
- phylogenetic community distance (1)
- quark gluon plasma (1)
- reproducibility (1)
- rigor (1)
- schizophrenia (1)
- spectra (1)
- standardization (1)
- stress (1)
- translocation partner genes (1)
- tropical forests (1)
- √sN N = 2.76 TeV (1)
Institute
- Physik (432)
- Frankfurt Institute for Advanced Studies (FIAS) (306)
- Informatik (257)
- Medizin (11)
- Geowissenschaften (4)
- Biochemie und Chemie (3)
- Informatik und Mathematik (3)
- Hochschulrechenzentrum (2)
- Biodiversität und Klima Forschungszentrum (BiK-F) (1)
- Biowissenschaften (1)
We report inclusive photon measurements about midrapidity ( |y| <0.5 ) from 197 Au + 197 Au collisions at sqrt[sNN ]=130 GeV at RHIC. Photon pair conversions were reconstructed from electron and positron tracks measured with the Time Projection Chamber (TPC) of the STAR experiment. With this method, an energy resolution of Delta E/E ~ 2% at 0.5 GeV has been achieved. Reconstructed photons have also been used to measure the transverse momentum ( pt ) spectra of pi 0 mesons about midrapidity ( |y| <1 ) via the pi 0 --> gamma gamma decay channel. The fractional contribution of the pi 0 --> gamma gamma decay to the inclusive photon spectrum decreases by 20%±5% between pt =1.65 GeV/c and pt =2.4 GeV/c in the most central events, indicating that relative to pi 0 --> gamma gamma decay the contribution of other photon sources is substantially increasing.
We present the first large-acceptance measurement of event-wise mean transverse momentum <pt> fluctuations for Au-Au collisions at nucleon-nucleon center-of-momentum collision energy sqrt[sNN] = 130 GeV. The observed nonstatistical <pt> fluctuations substantially exceed in magnitude fluctuations expected from the finite number of particles produced in a typical collision. The r.m.s. fractional width excess of the event-wise <pt> distribution is 13.7±0.1(stat) ±1.3(syst)% relative to a statistical reference, for the 15% most-central collisions and for charged hadrons within pseudorapidity range | eta |<1,2 pi azimuth, and 0.15 <= pt <= 2 GeV/c. The width excess varies smoothly but nonmonotonically with collision centrality and does not display rapid changes with centrality which might indicate the presence of critical fluctuations. The reported <pt> fluctuation excess is qualitatively larger than those observed at lower energies and differs markedly from theoretical expectations. Contributions to <pt> fluctuations from semihard parton scattering in the initial state and dissipation in the bulk colored medium are discussed.
We present the results of charged particle fluctuations measurements in Au+Au collisions at sqrt[sNN ]=130 GeV using the STAR detector. Dynamical fluctuations measurements are presented for inclusive charged particle multiplicities as well as for identified charged pions, kaons, and protons. The net charge dynamical fluctuations are found to be large and negative providing clear evidence that positive and negative charged particle production is correlated within the pseudorapidity range investigated. Correlations are smaller than expected based on model-dependent predictions for a resonance gas or a quark-gluon gas which undergoes fast hadronization and freeze-out. Qualitative agreement is found with comparable scaled p+p measurements and a heavy ion jet interaction generation model calculation based on independent particle collisions, although a small deviation from the 1/N scaling dependence expected from this model is observed.
We report the first observations of the first harmonic (directed flow, v1) and the fourth harmonic (v4), in the azimuthal distribution of particles with respect to the reaction plane in Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). Both measurements were done taking advantage of the large elliptic flow (v2) generated at RHIC. From the correlation of v2 with v1 it is determined that v2 is positive, or in-plane. The integrated v4 is about a factor of 10 smaller than v2. For the sixth (v6) and eighth (v8) harmonics upper limits on the magnitudes are reported.
The ALICE Zero Degree Calorimeter system (ZDC) is composed of two identical sets of calorimeters, placed at opposite sides with respect to the interaction point, 114 meters away from it, complemented by two small forward electromagnetic calorimeters (ZEM). Each set of detectors consists of a neutron (ZN) and a proton (ZP) ZDC. They are placed at zero degrees with respect to the LHC axis and allow to detect particles emitted close to beam direction, in particular neutrons and protons emerging from hadronic heavy-ion collisions (spectator nucleons) and those emitted from electromagnetic processes. For neutrons emitted by these two processes, the ZN calorimeters have nearly 100% acceptance.
During the √sNN = 2.76 TeV Pb-Pb data-taking, the ALICE Collaboration studied forward neutron emission with a dedicated trigger, requiring a minimum energy deposition in at least one of the two ZN. By exploiting also the information of the two ZEM calorimeters it has been possible to separate the contributions of electromagnetic and hadronic processes and to study single neutron vs. multiple neutron emission.
The measured cross sections of single and mutual electromagnetic dissociation of Pb nuclei at √sNN = 2.76 TeV, with neutron emission, are σsingle EMD = 187:4 ± 0.2 (stat.)−11.2+13.2 (syst.) b and σmutual EMD = 5.7 ± 0.1 (stat.) ±0.4 (syst.) b, respectively [1]. This is the first measurement of electromagnetic dissociation of 208Pb nuclei at the LHC energies, allowing a test of electromagnetic dissociation theory in a new energy regime. The experimental results are compared to the predictions from a relativistic electromagnetic dissociation model.
The production of inclusive, prompt and non-prompt J/ψ was studied for the first time at midrapidity (−1.37 < ycms < 0.43) in p-Pb collisions at √sNN = 8.16 TeV with the ALICE detector at the LHC. The inclusive J/ψ mesons were reconstructed in the dielectron decay channel in the transverse momentum (pT) interval 0 < pT < 14 GeV/c and the prompt and non-prompt contributions were separated on a statistical basis for pT > 2 GeV/c. The study of the J/ψ mesons in the dielectron channel used for the first time in ALICE online single-electron triggers from the Transition Radiation Detector, providing a data sample corresponding to an integrated luminosity of 689 ± 13 μb−1. The proton-proton reference cross section for inclusive J/ψ was obtained based on interpolations of measured data at different centre-of-mass energies and a universal function describing the pT-differential J/ψ production cross sections. The pT-differential nuclear modification factors RpPb of inclusive, prompt, and non-prompt J/ψ are consistent with unity and described by theoretical models implementing only nuclear shadowing.
The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified charged pion pairs in Au+Au collisions at sqrt[sNN]=130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization.
Azimuthal anisotropy (v2) and two-particle angular correlations of high pT charged hadrons have been measured in Au+Au collisions at sqrt[sNN]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high pT partons. The monotonic rise of v2(pT) for pT<2 GeV/c is consistent with collective hydrodynamical flow calculations. At pT>3 GeV/c, a saturation of v2 is observed which persists up to pT=6 GeV/c.
Azimuthal anisotropy (v2) and two-particle angular correlations of high pT charged hadrons have been measured in Au+Au collisions at sqrt[sNN]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high pT partons. The monotonic rise of v2(pT) for pT<2 GeV/c is consistent with collective hydrodynamical flow calculations. At pT>3 GeV/c, a saturation of v2 is observed which persists up to pT=6 GeV/c.
The transverse mass spectra and midrapidity yields for Xi s and Omega s are presented. For the 10% most central collisions, the Xi -bar+/h- ratio increases from the Super Proton Synchrotron to the Relativistic Heavy Ion Collider energies while the Xi -/h- stays approximately constant. A hydrodynamically inspired model fit to the Xi spectra, which assumes a thermalized source, seems to indicate that these multistrange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to pi , K, p, and Lambda s.
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 the low density (dilute gas) limit. Among the effects that can complicate the interpretation of elliptic flow measurements are azimuthal correlations that are unrelated to the reaction plane (nonflow correlations). Using data for Au + Au collisions at sqrt[sNN]=130 GeV from the STAR time projection chamber, it is found that four-particle correlation analyses can reliably separate flow and nonflow correlation signals. The latter account for on average about 15% of the observed second-harmonic azimuthal correlation, with the largest relative contribution for the most peripheral and the most central collisions. The results are also corrected for the effect of flow variations within centrality bins. This effect is negligible for all but the most central bin, where the correction to the elliptic flow is about a factor of 2. A simple new method for two-particle flow analysis based on scalar products is described. An analysis based on the distribution of the magnitude of the flow vector is also described.
We report the first observation of K*(892)0--> pi K in relativistic heavy ion collisions. The transverse momentum spectrum of (K*0+K*0)/2 from central Au+Au collisions at sqrt[sNN]=130 GeV is presented. The ratios of the K*0 yield derived from these data to the yields of negative hadrons, charged kaons, and phi mesons have been measured in central and minimum bias collisions and compared with model predictions and comparable e+e-, pp, and p-barp results. The data indicate no dramatic reduction of K*0 production in relativistic heavy ion collisions despite expected losses due to rescattering effects.
The STAR Collaboration reports the first observation of exclusive rho 0 photoproduction, AuAu-->AuAu rho 0, and rho 0 production accompanied by mutual nuclear Coulomb excitation, AuAu-->Au [star] Au [star] rho 0, in ultraperipheral heavy-ion collisions. The rho 0 have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrt[sNN]=130 GeV agree with theoretical predictions treating rho 0 production and Coulomb excitation as independent processes.
We report STAR results on the azimuthal anisotropy parameter v2 for strange particles K0S, Lambda , and Lambda -bar at midrapidity in Au+Au collisions at sqrt[sNN]=130 GeV at the Relativistic Heavy Ion Collider. The value of v2 as a function of transverse momentum, pt, of the produced particle and collision centrality is presented for both particles up to pt~3.0 GeV/c. A strong pt dependence in v2 is observed up to 2.0 GeV/c. The v2 measurement is compared with hydrodynamic model calculations. The physics implications of the pt integrated v2 magnitude as a function of particle mass are also discussed.
Inclusive transverse momentum distributions of charged hadrons within 0.2<pT<6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at sqrt[sNN]=130 GeV. Hadron yields are suppressed at high pT in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-pT hadron production in heavy-ion collisions at high energy.
We report the first measurement of strange ( Lambda ) and antistrange ( Lambda -bar) baryon production from sqrt[sNN]=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Lambda and Lambda -bar hyperons is found to be approximately proportional to the number of negative hadrons. The production of Lambda -bar hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone.
We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions at sqrt[sNN] = 130 GeV by the STAR experiment at RHIC. The antiproton transverse mass distributions in the measured transverse momentum range of 0.25<pperp<0.95 GeV/c are found to fall less steeply for more central collisions. The extrapolated antiproton rapidity density is found to scale approximately with the negative hadron multiplicity density.
A newly developed observable for correlations between symmetry planes, which characterize the direction of the anisotropic emission of produced particles, is measured in Pb-Pb collisions at sNN−−−√=2.76 TeV with ALICE. This so-called Gaussian Estimator allows for the first time the study of these quantities without the influence of correlations between different flow amplitudes. The centrality dependence of various correlations between two, three and four symmetry planes is presented. The ordering of magnitude between these symmetry plane correlations is discussed and the results of the Gaussian Estimator are compared with measurements of previously used estimators. The results utilizing the new estimator lead to significantly smaller correlations than reported by studies using the Scalar Product method. Furthermore, the obtained symmetry plane correlations are compared to state-of-the-art hydrodynamic model calculations for the evolution of heavy-ion collisions. While the model predictions provide a qualitative description of the data, quantitative agreement is not always observed, particularly for correlators with significant non-linear response of the medium to initial state anisotropies of the collision system. As these results provide unique and independent information, their usage in future Bayesian analysis can further constrain our knowledge on the properties of the QCD matter produced in ultrarelativistic heavy-ion collisions.
The measurement of the production of deuterons, tritons and 3He and their antiparticles in Pb-Pb collisions at √sNN = 5.02 TeV is presented in this article. The measurements are carried out at midrapidity (y|< 0.5) as a function of collision centrality using the ALICE detector. The pT-integrated yields, the coalescence parameters and the ratios to protons and antiprotons are reported and compared with nucleosynthesis models. The comparison of these results in different collision systems at different center-of-mass collision energies reveals a suppression of nucleus production in small systems. In the Statistical Hadronisation Model framework, this can be explained by a small correlation volume where the baryon number is conserved, as already shown in previous fluctuation analyses. However, a different size of the correlation volume is required to describe the proton yields in the same data sets. The coalescence model can describe this suppression by the fact that the wave functions of the nuclei are large and the fireball size starts to become comparable and even much smaller than the actual nucleus at low multiplicities.
Two-pion correlation functions in Au+Au collisions at sqrt[sNN] = 130 GeV have been measured by the STAR (solenoidal tracker at RHIC) detector. The source size extracted by fitting the correlations grows with event multiplicity and decreases with transverse momentum. Anomalously large sizes or emission durations, which have been suggested as signals of quark-gluon plasma formation and rehadronization, are not observed. The Hanbury Brown-Twiss parameters display a weak energy dependence over a broad range in sqrt[sNN].