Showing papers by "Claude Andre Pruneau published in 2002"
TL;DR: In this paper, the transverse momentum distributions of charged hadrons within 0.2 < p T < 6.0 GeV/c have been measured over a broad range of centrality for Au + Au collisions at S N N = 130 GeV.
Abstract: Inclusive transverse momentum distributions of charged hadrons within 0.2 < p T < 6.0 GeV/c have been measured over a broad range of centrality for Au + Au collisions at S N N = 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-p T hadron production in heavy-ion collisions at high energy.
449 citations
TL;DR: In this article, the transverse momentum distributions of charged hadrons within a range of centrality for collisions at high energy collisions were measured over a broad range of local centralities.
Abstract: Inclusive transverse momentum distributions of charged hadrons within $02l{p}_{T}l60\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/c$ have been measured over a broad range of centrality for $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at $\sqrt{{s}_{NN}}=130\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$ Hadron yields are suppressed at high ${p}_{T}$ 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-${p}_{T}$ hadron production in heavy-ion collisions at high energy
443 citations
TL;DR: In this article, the authors show that four-particle correlation analyses can reliably separate flow and non-flow correlation signals, with the latter account for on average about 15 percent of the observed second-harmonic azimuthal correlation.
Abstract: 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 (non-flow correlations). Using data for Au + Au collisions at {radical}s{sub NN} = 130 GeV from the STAR TPC, it is found that four-particle correlation analyses can reliably separate flow and non-flow correlation signals. The latter account for on average about 15 percent 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 two. 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.
313 citations
TL;DR: In this article, various measures of net charge (conserved quantities) fluctuations proposed for the identification of critical phenomena in heavy ion collisions are discussed and the dynamical component of fluctuations of the net charge can be expressed simply in terms of integrals of two-and single-particle densities.
Abstract: We discuss various measures of net charge (conserved quantities) fluctuations proposed for the identification of critical phenomena in heavy ion collisions. We show the dynamical component of fluctuations of the net charge can be expressed simply in terms of integrals of two- and single-particle densities. We discuss the dependence of the fluctuation observables on detector acceptance, detection efficiency and colliding system size, and collision centrality. Finally, we present a toy model of particle production including charge conservation and resonance production to gauge the effects of such resonances and finite acceptance on the net-charge fluctuations.
168 citations
TL;DR: The first observation of rho(0) photoproduction, AuAu-->AuAurho( 0), and rho (0) production accompanied by mutual nuclear Coulomb excitation in ultraperipheral heavy-ion collisions was reported by the STAR Collaboration as mentioned in this paper.
Abstract: The STAR Collaboration reports the first observation of exclusive rho(0) photoproduction, AuAu-->AuAurho(0), and rho(0) production accompanied by mutual nuclear Coulomb excitation, AuAu-->Au*Au*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[s(NN)]=130 GeV agree with theoretical predictions treating rho(0) production and Coulomb excitation as independent processes.
93 citations
TL;DR: In this article, the authors reported the first measurement of strange (Λ) and antistrange (λ) baryon production from √(sNN)=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider.
Abstract: We report the first measurement of strange (Λ) and antistrange (Λ¯¯¯) baryon production from √(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 Λ and Λ¯¯¯ hyperons is found to be approximately proportional to the number of negative hadrons. The production of Λ¯¯¯ 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.
87 citations
TL;DR: In this paper, the first measurement of midrapidity vector meson phi production in Au+Au collisions at RHIC (roots(NN)=130 GeV) from the STAR detector was presented.
Abstract: We present the first measurement of midrapidity vector meson phi production in Au+Au collisions at RHIC (roots(NN)=130 GeV) from the STAR detector. For the 11% highest multiplicity collisions, the slope parameter from an exponential fit to the transverse mass distribution is T=379+/-50(stat)+/-45(syst) MeV, the yield dN/dy=5.73+/-0.37(stat)+/-0.69(syst) per event, and the ratio N-phi/Nh- is found to be 0.021+/-0.001(stat)+/-0.004(syst). The measured ratio N-phi/N-h(-) and T for the phi meson at midrapidity do not change for the selected multiplicity bins.
76 citations
TL;DR: In this paper, the authors report results on the azimuthal anisotropy parameter v(2) for strange particles K(0)(S), Lambda, and Lambda at midrapidity in Au+Au collisions at the Relativistic Heavy Ion Collider.
Abstract: We report STAR results on the azimuthal anisotropy parameter v(2) for strange particles K(0)(S), Lambda, and Lambda at midrapidity in Au+Au collisions at sqrt[s(NN)]=130 GeV at the Relativistic Heavy Ion Collider The value of v(2) as a function of transverse momentum, p(t), of the produced particle and collision centrality is presented for both particles up to p(t) approximately 30 GeV/c A strong p(t) dependence in v(2) is observed up to 20 GeV/c The v(2) measurement is compared with hydrodynamic model calculations The physics implications of the p(t) integrated v(2) magnitude as a function of particle mass are also discussed
61 citations
TL;DR: In this paper, the transverse momentum spectrum of central Au+Au collisions at ≈130$ GeV was observed and the ratios of the 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 $\bar{p}p$ results.
Abstract: We report the first observation of $K^{\star}(892)^{0}\to\pi K$ in relativistic heavy ion collisions. The transverse momentum spectrum of $(K^{\star0}+\bar{K}^{\star0})/2$ from central Au+Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV is presented. The ratios of the $K^{\star0}$ 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 $\bar{p}p$ results. The data indicate no dramatic reduction of $K^{\star0}$ production in relativistic heavy ion collisions despite expected losses due to rescattering effects.
46 citations
45 citations
Journal Article•
TL;DR: The first observation of exclusive ρ 0 photoproduction with mutual nuclear Coulomb excitation in ultraperipheral heavy-ion collisions was reported by the STAR Collaboration as mentioned in this paper.
Abstract: The STAR Collaboration reports the first observation of exclusive ρ 0 photoproduction, AuAu → AuAuρ 0 , and p° production accompanied by mutual nuclear Coulomb excitation, AuAu → Au*Au*ρ 0 , in ultraperipheral heavy-ion collisions. The p° have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at √S N N = 130 GeV agree with theoretical predictions treating p° production and Coulomb excitation as independent processes.
TL;DR: The STAR detector has made a variety of measurements of strange and other hadronic species in Au+Au collisions at s N N = 130 GeV and a comparison of kaon and pion production enables an examination of the systematics of strangeness production with energy as mentioned in this paper.
Abstract: The STAR detector has made a variety of measurements of strange and other hadronic species in Au+Au collisions at s N N = 130 GeV. A comparison of kaon and pion production enables an examination of the systematics of strangeness production with energy by comparing them to lower energy collisions. Anti-baryon to baryon ratios indicate a much reduced net-baryon density and transverse momentum spectra show that a picture of transverse expansion seems appropriate.
21 Jan 2002-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The current status of the STAR Silicon Vertex Tracker (SVT) is discussed in this article, where the performance of the SVT is compared to those of the original SDD tracker.
Abstract: The current status of the STAR Silicon Vertex Tracker (SVT) is presented. The performance of the Silicon Drift Detectors (SDD) is discussed. Results for a recent 15 layer SDD tracker which prototypes all components of the SVT are presented. The enhanced physics capabilities of the STAR detector due to the addition of the SVT are addressed.
TL;DR: In this paper, the authors reported the first measurement of strange and antistrange baryon production from the Relativistic Heavy Ion Collider (RHIC) and reported that the yield of the strange baryons is approximately proportional to the number of negative hadrons.
Abstract: We report the first measurement of strange ($\ensuremath{\Lambda}$) and antistrange ($\overline{\ensuremath{\Lambda}}$) baryon production from $\sqrt{{s}_{NN}}=130\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$ $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ 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 $\ensuremath{\Lambda}$ and $\overline{\ensuremath{\Lambda}}$ hyperons is found to be approximately proportional to the number of negative hadrons. The production of $\overline{\ensuremath{\Lambda}}$ 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.
Journal Article•