cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.17182/hepdata.96848.v1/t14
title: "Figure 20 down" of "Strange particle production in p + p collisions at s**(1/2) = 200-GeV."

description: Parameters of ratio data to statistical model fit using THERMUS. Filled circles are ratios from $\sqrt{s}$=200 GeV collisions in STAR. Solid lines are the results from the statis- tical model fit. All ratios to the left of the vertical line were used in the fit. The $(\Omega^{-}+\overline{\Omega^{+}})/\Xi^{-}$ ratio was then predicted from the fit results. The dashed lines in the lower panel are guides for the eye at 1 σ.
description: We present strange particle spectra and yields measured at mid-rapidity in $\sqrt{s}$=200 GeV proton-proton (p+p) collisions at RHIC. We find that the previously observed universal transverse mass (mT≡$\sqrt{pT2+m2}$) scaling of hadron production in p+p collisions seems to break down at higher \mt and that there is a difference in the shape of the \mt spectrum between baryons and mesons. We observe mid-rapidity anti-baryon to baryon ratios near unity for Λ and Ξ baryons and no dependence of the ratio on transverse momentum, indicating that our data do not yet reach the quark-jet dominated region. We show the dependence of the mean transverse momentum (\mpt) on measured charged particle multiplicity and on particle mass and infer that these trends are consistent with gluon-jet dominated particle production. The data are compared to previous measurements from CERN-SPS, ISR and FNAL experiments and to Leading Order (LO) and Next to Leading order (NLO) string fragmentation model predictions. We infer from these comparisons that the spectral shapes and particle yields from p+p collisions at RHIC energies have large contributions from gluon jets rather than quark jets.
DOI: 10.17182/hepdata.96905.v1/t1
title: "Figure 1 (left)" of "Directed Flow of Identified Particles in Au + Au Collisions at $\sqrtsNN = 200$ GeV at RHIC"

description: $v_1$ for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ (left panel), p and $\bar{p}$ (right panel) as a function of rapidity for 10-70$\%$ $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV. The lines present the linear fit to the $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$’s $v_1$(y) respectively. Data points around $y = 0.29$ are slightly shifted horizontally to avoid overlapping.
description: STAR’s measurements of directed flow ($v_1$) around midrapidity for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$ in $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV are presented. A negative $v_1$(y) slope is observed for most of produced particles ($\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ and $\bar{p}$). In 5-30$\%$ central collisions a sizable difference is present between the $v_1$(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The $v_1$ excitation function is presented. Comparisons to model calculations (RQMD,UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of $v_1$ for both pions and protons, none of them can describe $v_1$(y) for pions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the $v_1$(y) slopes of protons and antiprotons.
DOI: 10.17182/hepdata.96905.v1/t2
title: "Figure 1 (left) for $K^{\pm}$ only" of "Directed Flow of Identified Particles in Au + Au Collisions at $\sqrtsNN = 200$ GeV at RHIC"

description: $v_1$ for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ (left panel), p and $\bar{p}$ (right panel) as a function of rapidity for 10-70$\%$ $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV. The lines present the linear fit to the $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$’s $v_1$(y) respectively. Data points around $y = 0.29$ are slightly shifted horizontally to avoid overlapping.
description: STAR’s measurements of directed flow ($v_1$) around midrapidity for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$ in $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV are presented. A negative $v_1$(y) slope is observed for most of produced particles ($\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ and $\bar{p}$). In 5-30$\%$ central collisions a sizable difference is present between the $v_1$(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The $v_1$ excitation function is presented. Comparisons to model calculations (RQMD,UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of $v_1$ for both pions and protons, none of them can describe $v_1$(y) for pions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the $v_1$(y) slopes of protons and antiprotons.
DOI: 10.17182/hepdata.96905.v1/t3
title: "Figure 1 (right)" of "Directed Flow of Identified Particles in Au + Au Collisions at $\sqrtsNN = 200$ GeV at RHIC"

description: $v_1$ for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ (left panel), p and $\bar{p}$ (right panel) as a function of rapidity for 10-70$\%$ $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV. The lines present the linear fit to the $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$’s $v_1$(y) respectively. Data points around $y = 0.29$ are slightly shifted horizontally to avoid overlapping.
description: STAR’s measurements of directed flow ($v_1$) around midrapidity for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$ in $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV are presented. A negative $v_1$(y) slope is observed for most of produced particles ($\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ and $\bar{p}$). In 5-30$\%$ central collisions a sizable difference is present between the $v_1$(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The $v_1$ excitation function is presented. Comparisons to model calculations (RQMD,UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of $v_1$ for both pions and protons, none of them can describe $v_1$(y) for pions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the $v_1$(y) slopes of protons and antiprotons.
DOI: 10.17182/hepdata.96905.v1/t4
title: "Figure 2" of "Directed Flow of Identified Particles in Au + Au Collisions at $\sqrtsNN = 200$ GeV at RHIC"

description: Model calculations of pion (left panel) and proton (right panel) $v_1$(y) for 10-70$\%$ $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV. QGSM model presents the basic Quark-Gluon String model with parton recombination. Hydro model presents the hydrodynamic expansion from a tilted source (Please note that proton v1 in this figure is the same as in Figure 1 right).
description: STAR’s measurements of directed flow ($v_1$) around midrapidity for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$ in $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV are presented. A negative $v_1$(y) slope is observed for most of produced particles ($\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ and $\bar{p}$). In 5-30$\%$ central collisions a sizable difference is present between the $v_1$(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The $v_1$ excitation function is presented. Comparisons to model calculations (RQMD,UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of $v_1$ for both pions and protons, none of them can describe $v_1$(y) for pions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the $v_1$(y) slopes of protons and antiprotons.
DOI: 10.17182/hepdata.96905.v1/t5
title: "Figure 3" of "Directed Flow of Identified Particles in Au + Au Collisions at $\sqrtsNN = 200$ GeV at RHIC"

description: Charged pions (solid stars), protons (solid circles) and antiprotons (solid squares) $v_1$(y) slope (d$v_1$/dy) at midrapidity as a function of centrality for $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV.
description: STAR’s measurements of directed flow ($v_1$) around midrapidity for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$ in $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV are presented. A negative $v_1$(y) slope is observed for most of produced particles ($\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ and $\bar{p}$). In 5-30$\%$ central collisions a sizable difference is present between the $v_1$(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The $v_1$ excitation function is presented. Comparisons to model calculations (RQMD,UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of $v_1$ for both pions and protons, none of them can describe $v_1$(y) for pions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the $v_1$(y) slopes of protons and antiprotons.
DOI: 10.3535/hdn-bd6-q7d
title: Bromus hordeaceus L.

description: Digital Specimen for the physical specimen hosted at Botanic Garden and Botanical Museum Berlin.
DOI: 10.17182/hepdata.96905.v1/t6
title: "Figure 4" of "Directed Flow of Identified Particles in Au + Au Collisions at $\sqrtsNN = 200$ GeV at RHIC"

description: Proton $v_1$($y^{\prime}$) slope (d$v_1$/d$y^{\prime}$) at midrapidity as a function of center of mass collision energy, where $y^{\prime} = y/y_{beam}$.
description: STAR’s measurements of directed flow ($v_1$) around midrapidity for $\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$, p and $\bar{p}$ in $Au + Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV are presented. A negative $v_1$(y) slope is observed for most of produced particles ($\pi^{\pm}$, $K^{\pm}$, $K_{S}^{0}$ and $\bar{p}$). In 5-30$\%$ central collisions a sizable difference is present between the $v_1$(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The $v_1$ excitation function is presented. Comparisons to model calculations (RQMD,UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of $v_1$ for both pions and protons, none of them can describe $v_1$(y) for pions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the $v_1$(y) slopes of protons and antiprotons.
DOI: 10.17182/hepdata.96906.v1/t1
title: "Figure 3" of "Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions"

description: $v_{2}(\eta)$ for charged hadrons, $0.15 &lt; p_{T} &lt; 2.0$ GeV/c, centrality $10-40\%$, from $Au+Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV.
description: We present STAR results on the elliptic flow $v_2$ of charged hadrons, strange and multi-strange particles from $\sqrt{s_{NN}} = 200$ GeV $Au+Au$ collisions at RHIC. The detailed study of the centrality dependence of $v_{2}$ over a broad transverse momentum range is presented. Comparison of different analysis methods are made in order to estimate systematic uncertainties. In order to discuss the non-flow effect, we have performed the first analysis of $v_{2}$ with the Lee-Yang Zero method for $K_{S}^{0}$ and $\Lambda$. In the relatively low $p_{T}$ region, $p_{T} \le 2$ GeV/c, a scaling with $m_{T}−m$ is observed for identified hadrons in each centrality bin studied. However, we do not observe $v_{2}(p_{T})$ scaled by the participant eccentricity to be independent of centrality. At higher $p_{T}$ , $2 \le p_{T} \le 6$ GeV/c, $v_{2}$ scales 3 with quark number for all hadrons studied. For the multi-strange hadron $\Omega$, which does not suffer appreciable hadronic interactions, the values of $v_{2}$ are consistent with both $m_{T}−m$ scaling at low $p_{T}$ and number-of-quark scaling at intermediate $p_{T}$. As a function of collision centrality, an increase of $p_{T}$-integrated $v_{2}$ scaled by the participant eccentricity has been observed, indicating a stronger collective flow in more central $Au+Au$ collisions.
DOI: 10.17182/hepdata.96906.v1/t2
title: "Figure 4a (Event Plane)" of "Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions"

description: $v_{2}$ as a function of $p_{T}$ for charged hadrons with $|\eta| &lt; 1.0$ in 10–40$%$ $Au+Au$ collisions, at $\sqrt{s_{NN}} = 200$ GeV, from the Event Plane method (open circles).
description: We present STAR results on the elliptic flow $v_2$ of charged hadrons, strange and multi-strange particles from $\sqrt{s_{NN}} = 200$ GeV $Au+Au$ collisions at RHIC. The detailed study of the centrality dependence of $v_{2}$ over a broad transverse momentum range is presented. Comparison of different analysis methods are made in order to estimate systematic uncertainties. In order to discuss the non-flow effect, we have performed the first analysis of $v_{2}$ with the Lee-Yang Zero method for $K_{S}^{0}$ and $\Lambda$. In the relatively low $p_{T}$ region, $p_{T} \le 2$ GeV/c, a scaling with $m_{T}−m$ is observed for identified hadrons in each centrality bin studied. However, we do not observe $v_{2}(p_{T})$ scaled by the participant eccentricity to be independent of centrality. At higher $p_{T}$ , $2 \le p_{T} \le 6$ GeV/c, $v_{2}$ scales 3 with quark number for all hadrons studied. For the multi-strange hadron $\Omega$, which does not suffer appreciable hadronic interactions, the values of $v_{2}$ are consistent with both $m_{T}−m$ scaling at low $p_{T}$ and number-of-quark scaling at intermediate $p_{T}$. As a function of collision centrality, an increase of $p_{T}$-integrated $v_{2}$ scaled by the participant eccentricity has been observed, indicating a stronger collective flow in more central $Au+Au$ collisions.
DOI: 10.17182/hepdata.96906.v1/t3
title: "Figure 4a (4-particle cumulant)" of "Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions"

description: $v_{2}$ as a function of $p_{T}$ for charged hadrons with $|\eta| &lt; 1.0$ in 10–40$%$ $Au+Au$ collisions, at $\sqrt{s_{NN}} = 200$ GeV, from the 4-particle cumulant method (solid squares).
description: We present STAR results on the elliptic flow $v_2$ of charged hadrons, strange and multi-strange particles from $\sqrt{s_{NN}} = 200$ GeV $Au+Au$ collisions at RHIC. The detailed study of the centrality dependence of $v_{2}$ over a broad transverse momentum range is presented. Comparison of different analysis methods are made in order to estimate systematic uncertainties. In order to discuss the non-flow effect, we have performed the first analysis of $v_{2}$ with the Lee-Yang Zero method for $K_{S}^{0}$ and $\Lambda$. In the relatively low $p_{T}$ region, $p_{T} \le 2$ GeV/c, a scaling with $m_{T}−m$ is observed for identified hadrons in each centrality bin studied. However, we do not observe $v_{2}(p_{T})$ scaled by the participant eccentricity to be independent of centrality. At higher $p_{T}$ , $2 \le p_{T} \le 6$ GeV/c, $v_{2}$ scales 3 with quark number for all hadrons studied. For the multi-strange hadron $\Omega$, which does not suffer appreciable hadronic interactions, the values of $v_{2}$ are consistent with both $m_{T}−m$ scaling at low $p_{T}$ and number-of-quark scaling at intermediate $p_{T}$. As a function of collision centrality, an increase of $p_{T}$-integrated $v_{2}$ scaled by the participant eccentricity has been observed, indicating a stronger collective flow in more central $Au+Au$ collisions.
DOI: 10.17182/hepdata.96906.v1/t4
title: "Figure 4a (Lee-Yang Zero)" of "Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions"

description: $v_{2}$ as a function of $p_{T}$ for charged hadrons with $|\eta| &lt; 1.0$ in 10–40$%$ $Au+Au$ collisions, at $\sqrt{s_{NN}} = 200$ GeV, from the Lee-Yang Zero method (solid circles) with Sum Generating Function.
description: We present STAR results on the elliptic flow $v_2$ of charged hadrons, strange and multi-strange particles from $\sqrt{s_{NN}} = 200$ GeV $Au+Au$ collisions at RHIC. The detailed study of the centrality dependence of $v_{2}$ over a broad transverse momentum range is presented. Comparison of different analysis methods are made in order to estimate systematic uncertainties. In order to discuss the non-flow effect, we have performed the first analysis of $v_{2}$ with the Lee-Yang Zero method for $K_{S}^{0}$ and $\Lambda$. In the relatively low $p_{T}$ region, $p_{T} \le 2$ GeV/c, a scaling with $m_{T}−m$ is observed for identified hadrons in each centrality bin studied. However, we do not observe $v_{2}(p_{T})$ scaled by the participant eccentricity to be independent of centrality. At higher $p_{T}$ , $2 \le p_{T} \le 6$ GeV/c, $v_{2}$ scales 3 with quark number for all hadrons studied. For the multi-strange hadron $\Omega$, which does not suffer appreciable hadronic interactions, the values of $v_{2}$ are consistent with both $m_{T}−m$ scaling at low $p_{T}$ and number-of-quark scaling at intermediate $p_{T}$. As a function of collision centrality, an increase of $p_{T}$-integrated $v_{2}$ scaled by the participant eccentricity has been observed, indicating a stronger collective flow in more central $Au+Au$ collisions.
DOI: 10.17182/hepdata.96906.v1/t5
title: "Figure 4 (Event Plane $0-80\%$)" of "Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions"

description: $v_{2}$ as a function of $p_{T}$ for charged hadrons with $|\eta| &lt; 1.0$ in 0–80$%$ $Au+Au$ collisions, at $\sqrt{s_{NN}} = 200$ GeV, from the Event Plane method.
description: We present STAR results on the elliptic flow $v_2$ of charged hadrons, strange and multi-strange particles from $\sqrt{s_{NN}} = 200$ GeV $Au+Au$ collisions at RHIC. The detailed study of the centrality dependence of $v_{2}$ over a broad transverse momentum range is presented. Comparison of different analysis methods are made in order to estimate systematic uncertainties. In order to discuss the non-flow effect, we have performed the first analysis of $v_{2}$ with the Lee-Yang Zero method for $K_{S}^{0}$ and $\Lambda$. In the relatively low $p_{T}$ region, $p_{T} \le 2$ GeV/c, a scaling with $m_{T}−m$ is observed for identified hadrons in each centrality bin studied. However, we do not observe $v_{2}(p_{T})$ scaled by the participant eccentricity to be independent of centrality. At higher $p_{T}$ , $2 \le p_{T} \le 6$ GeV/c, $v_{2}$ scales 3 with quark number for all hadrons studied. For the multi-strange hadron $\Omega$, which does not suffer appreciable hadronic interactions, the values of $v_{2}$ are consistent with both $m_{T}−m$ scaling at low $p_{T}$ and number-of-quark scaling at intermediate $p_{T}$. As a function of collision centrality, an increase of $p_{T}$-integrated $v_{2}$ scaled by the participant eccentricity has been observed, indicating a stronger collective flow in more central $Au+Au$ collisions.
DOI: 10.17182/hepdata.96906.v1/t6
title: "Figure 5a (Event Plane)" of "Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions"

description: $p_{T}$ integrated charged hadron $v_{2}$ in the TPC as a function of geometrical cross section. Shown are the Event Plane method ($v_{2}${EP}) (open circles). All data are from $Au+Au$ collisions, at $\sqrt{s_{NN}} = 200$ GeV. For the TPC, $|\eta|&lt; 1.0$ was used.
description: We present STAR results on the elliptic flow $v_2$ of charged hadrons, strange and multi-strange particles from $\sqrt{s_{NN}} = 200$ GeV $Au+Au$ collisions at RHIC. The detailed study of the centrality dependence of $v_{2}$ over a broad transverse momentum range is presented. Comparison of different analysis methods are made in order to estimate systematic uncertainties. In order to discuss the non-flow effect, we have performed the first analysis of $v_{2}$ with the Lee-Yang Zero method for $K_{S}^{0}$ and $\Lambda$. In the relatively low $p_{T}$ region, $p_{T} \le 2$ GeV/c, a scaling with $m_{T}−m$ is observed for identified hadrons in each centrality bin studied. However, we do not observe $v_{2}(p_{T})$ scaled by the participant eccentricity to be independent of centrality. At higher $p_{T}$ , $2 \le p_{T} \le 6$ GeV/c, $v_{2}$ scales 3 with quark number for all hadrons studied. For the multi-strange hadron $\Omega$, which does not suffer appreciable hadronic interactions, the values of $v_{2}$ are consistent with both $m_{T}−m$ scaling at low $p_{T}$ and number-of-quark scaling at intermediate $p_{T}$. As a function of collision centrality, an increase of $p_{T}$-integrated $v_{2}$ scaled by the participant eccentricity has been observed, indicating a stronger collective flow in more central $Au+Au$ collisions.
DOI: 10.3535/1gc-mn8-p9t
title: Molinia caerulea (L.) Moench

description: Digital Specimen for the physical specimen hosted at Botanic Garden and Botanical Museum Berlin.
DOI: 10.17182/hepdata.96906.v1/t10
title: "Figure 6a Lambda($\eta$-sub)" of "Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions"

description: $v_{2}$ as a function of $p_{T}$ for $10–40\%$ centrality using $\eta$-subevent method (open crosses), are shown in (a) for $\Lambda$. All data are from $\sqrt{s_{NN}} = 200$ GeV $Au+Au$ collisions.
description: We present STAR results on the elliptic flow $v_2$ of charged hadrons, strange and multi-strange particles from $\sqrt{s_{NN}} = 200$ GeV $Au+Au$ collisions at RHIC. The detailed study of the centrality dependence of $v_{2}$ over a broad transverse momentum range is presented. Comparison of different analysis methods are made in order to estimate systematic uncertainties. In order to discuss the non-flow effect, we have performed the first analysis of $v_{2}$ with the Lee-Yang Zero method for $K_{S}^{0}$ and $\Lambda$. In the relatively low $p_{T}$ region, $p_{T} \le 2$ GeV/c, a scaling with $m_{T}−m$ is observed for identified hadrons in each centrality bin studied. However, we do not observe $v_{2}(p_{T})$ scaled by the participant eccentricity to be independent of centrality. At higher $p_{T}$ , $2 \le p_{T} \le 6$ GeV/c, $v_{2}$ scales 3 with quark number for all hadrons studied. For the multi-strange hadron $\Omega$, which does not suffer appreciable hadronic interactions, the values of $v_{2}$ are consistent with both $m_{T}−m$ scaling at low $p_{T}$ and number-of-quark scaling at intermediate $p_{T}$. As a function of collision centrality, an increase of $p_{T}$-integrated $v_{2}$ scaled by the participant eccentricity has been observed, indicating a stronger collective flow in more central $Au+Au$ collisions.