Flow and interferometry results from Au+Au collisions at $\sqrt{{\text{s}}_{NN}}$ = 4.5 GeV

Abstract

The Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider (RHIC) was extended to energies below $\sqrt{{\text{s}}_{NN}}$ = 7.7 GeV in 2015 by successful implementation of the fixed-target mode of operation in the STAR (Solenoidal Track At RHIC) experiment. In the fixed-target mode, ions circulate in one ring of the collider and interact with a stationary target at the entrance of the STAR Time Projection Chamber. The first results for Au+Au collisions at $\sqrt{{\text{s}}_{NN}}$ = 4.5 GeV are presented, including directed and elliptic flow of identified hadrons, and radii from pion femtoscopy. The proton flow and pion femtoscopy results agree quantitatively with earlier measurements by Alternating Gradient Synchrotron experiments at similar energies. This validates running the STAR experiment in the fixed-target configuration. Pion directed and elliptic flow are presented for the first time at this beam energy. Pion and proton elliptic flow show behavior which hints at constituent quark scaling, but large error bars preclude reliable conclusions. The ongoing second phase of BES (BES-II) will provide fixed-target data sets with 100 times more events at each of several energies down to $\sqrt{{\text{s}}_{NN}}$ = 3.0 GeV.

arXiv comment18 pages, 20 figures; Contexts and figure caption was modified, one reference was added to address the referee's comments

References in corpus (62)

• Glauber Modeling in High Energy Nuclear Collisions
• Methods for analyzing anisotropic flow in relativistic nuclear collisions
• Flow Study in Relativistic Nuclear Collisions by Fourier Expansion of Azimuthal Particle Distributions
• The STAR Time Projection Chamber: A Unique Tool for Studying High Multiplicity Events at RHIC
• Femtoscopy in Relativistic Heavy Ion Collisions: Two Decades of Progress
• Comparison of Chemical Freeze-Out Criteria in Heavy-Ion Collisions
• Azimuthal anisotropy in Au+Au collisions at sqrtsNN = 200 GeV
• Particle-type dependence of azimuthal anisotropy and nuclear modification of particle production in Au+Au collisions at s(NN)**(1/2) = 200-GeV
• QCD and strongly coupled gauge theories: challenges and perspectives
• Energy Dependence of Moments of Net-proton Multiplicity Distributions at RHIC
• The Quark-Gluon Plasma in Equilibrium
• Flow analysis with cumulants: direct calculations
• Triangularity and Dipole Asymmetry in Heavy Ion Collisions
• Directed and elliptic flow of charged pions and protons in Pb+Pb collisions at 40 and 158A GeV
• Beam energy dependence of moments of the net-charge multiplicity distributions in Au+Au collisions at RHIC
• Two-pion Bose-Einstein correlations in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Identified Particle Elliptic Flow in Au+Au Collisions at $\sqrt{s_{{}_{NN}}}=130$ GeV}
• Observable implications of geometrical and dynamical aspects of freeze-out in heavy ion collisions
• Pion interferometry in Au+Au collisions at $\sqrt{{\mathrm{s}}_{{}_{\mathrm{NN}}}}$ = 200 GeV
• Beam-Energy Dependence of Directed Flow of Protons, Antiprotons and Pions in Au+Au Collisions
• The Time-Delay Signature of Quark-Gluon-Plasma Formation in Relativistic Nuclear Collisions
• Two-Particle Correlations in Relativistic Heavy-Ion Collisions
• Pion Interferometry of $\sqrt{s_{NN}}=130$ GeV Au+Au Collisions at RHIC
• QCD phase diagram and the critical point
• Elliptic Flow: Transition from out-of-plane to in-plane Emission in Au + Au Collisions
• Non-monotonic energy dependence of net-proton number fluctuations
• Systematics of pion emission in heavy ion collisions in the 1A GeV regime
• Beam-energy dependence of charge separation along the magnetic field in Au+Au collisions at RHIC
• Elliptic flow of identified hadrons in Au+Au collisions at $\sqrt{s_{NN}}=$ 7.7--62.4 GeV
• Skewness, kurtosis and the 5th and 6th order cumulants of net baryon-number distributions from lattice QCD confront high-statistics STAR data
• Excitation function of elliptic flow in Au+Au collisions and the nuclear matter equation of state
• A new cross term in the two-particle Hanbury-Brown-Twiss correlation function
• Sideward Flow in Au + Au Collisions Between 2A GeV and 8A GeV
• Energy dependence of elliptic flow over a large pseudorapidity range in Au+Au collisions at RHIC
• Dynamics of Ultra-Relativistic Nuclear Collisions with Heavy Beams: An Experimental Overview
• Observation of the critical end point in the phase diagram for hot and dense nuclear matter
• Beam-Energy Dependence of Directed Flow of $\Lambda$, $\bar{\Lambda }$, $K^{\pm }$, $K_s^0$ and $\varphi$ in Au+Au Collisions
• An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement
• Azimuthally sensitive Hanbury Brown-Twiss interferometry in Au+Au collisions at sqrt(s_{NN}) = 200 GeV
• Examination of the directed flow puzzle in heavy-ion collisions
• Directed flow, a signal for the phase transition in Relativistic Nuclear Collisions?
• Centrality dependence of identified particle elliptic flow in relativistic heavy ion collisions at sqrt(s)= 7.7--62.4 GeV
• Directed flow at midrapidity in heavy-ion collisions
• Directed Flow Indicates a Crossover Deconfinement Transition in Relativistic Nuclear Collisions
• Effects of momentum conservation on the analysis of anisotropic flow
• Centrality determination of Au+Au collisions at 1.23A GeV with HADES
• Momentum-dependent potential and collective flows within the relativistic quantum molecular dynamics approach based on relativistic mean-field theory
• Equation of state dependence of directed flow in a microscopic transport model
• Symmetry constraints for the emission angle dependence of Hanbury Brown--Twiss radii
• System, centrality, and transverse mass dependence of two-pion correlation radii in heavy ion collisions at 11.6 and 14.6 A-GeV
• Directed Flow of $\Lambda$-Hyperons in 2-6 AGeV Au+Au Collisions
• Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{{}_{NN}}}=62.4$ and 200 GeV
• The first moment of azimuthal anisotropy in nuclear collisions from AGS to LHC energies
• Directed and elliptic flow of charged particles in Cu+Cu collisions at $\sqrt{{\mathbf{s}}_{\mathbf{NN}}}=$ 22.4 GeV
• Identical pion intensity interferometry at sqrt(s_{NN})=2.4 GeV
• The Long Slow Death of the HBT Puzzle, Proceedings for QM 2009
• Breaking of the number-of-constituent-quark scaling for identified-particle elliptic flow as a signal of phase change in low-energy data taken at the BNL Relativistic Heavy Ion Collider (RHIC)
• Enhancement of elliptic flow can signal a first order phase transition in high energy heavy ion collisions
• Applicability of Monte Carlo Glauber models to relativistic heavy ion collision data
• Identical pion intensity interferometry in central Au+Au collisions at 1.23A GeV
• Correspondence between HBT radii and the emission zone in non-central heavy ion collisions
• Indications for a critical point in the phase diagram for hot and dense nuclear matter

Cited by in corpus (36)

• Cumulants and Correlation Functions of Net-proton, Proton and Antiproton Multiplicity Distributions in Au+Au Collisions at energies available at the BNL Relativistic Heavy Ion Collider
• Properties of the QCD Matter -- An Experimental Review of Selected Results from RHIC BES Program
• Status and initial physics performance studies of the MPD experiment at NICA
• Theoretical and Experimental Constraints for the Equation of State of Dense and Hot Matter
• Determination of the Equation of State from Nuclear Experiments and Neutron Star Observations
• Measurements of ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\Lambda }^4\mathrm{H}$ Lifetimes and Yields in Au+Au Collisions in the High Baryon Density Region
• The QCD phase diagram and Beam Energy Scan physics: a theory overview
• Beam Energy Dependence of Triton Production and Yield Ratio (${\mathrm{N}}_t\times {\mathrm{N}}_p/{\mathrm{N}}_d^2$) in Au+Au Collisions at RHIC
• Sensitivity of Au+Au collisions to the symmetric nuclear matter equation of state at 2 -- 5 nuclear saturation densities
• QCD Equation of State of Dense Nuclear Matter from a Bayesian Analysis of Heavy-Ion Collision Data
• Higher-Order Cumulants and Correlation Functions of Proton Multiplicity Distributions in $\sqrt{s_{\mathrm{NN}}}$ = 3 GeV Au+Au Collisions at the RHIC STAR Experiment
• Effects of a phase transition on two-pion interferometry in heavy-ion collisions at $\sqrt{s_{\mathrm{NN}}}=2.4-7.7$ GeV
• Directed flow of $\Lambda$ in high-energy heavy-ion collisions and $\Lambda$ potential in dense nuclear matter
• Observation of Directed Flow of Hypernuclei ${}_{\Lambda }^3$H and ${}_{\Lambda }^4$H in $\sqrt{s_{\mathrm{NN}}}$ = 3 GeV Au+Au Collisions at RHIC
• Structure in the speed of sound: from neutron stars to heavy-ion collisions
• Testing the phase transition parameters inside neutron stars with the production of protons and lambdas in relativistic heavy-ion collisions
• Double strangeness ${\Xi }^{-}$ production as a probe of nuclear equation of state at high densities
• Production of Protons and Light Nuclei in Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}$ = 3 GeV with the STAR Detector
• Repulsive $\Lambda$ potentials in dense neutron star matter and binding energy of $\Lambda$ in hypernuclei
• Mapping out the thermodynamic stability of a QCD equation of state with a critical point using active learning
• Thermalization and prethermalization in the soft-wall AdS/QCD model
• Probing the incompressibility of dense hadronic matter near QCD phase transition in relativistic heavy-ion collisions
• Speed of sound and polytropic index in QCD matter
• Examination of STAR fixed-target data on directed flow at $\sqrt{s_{NN}}=$ 3 and 4.5 GeV
• Heavy-Ion Collisions toward High-Density Nuclear Matter
• Optimal collision-energy range for realizing macroscopic high-baryon-density matter
• Density Functional Equation of State and Its Application to the Phenomenology of Heavy-Ion Collisions
• An overview of new measurements of flow, chirality, and vorticity from STAR experiment
• Violation of NCQ scaling in hadron elliptic flow in Au+Au collisions at $\sqrt{s_{NN}}=3.0-7.7GeV
• Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at $\sqrt{s_{NN}}=5.02$ TeV with the LHCb detector
• Predictions of baryon directed flow in heavy-ion collisions at high baryon density
• Global $\Lambda$ hyperon polarization in low-energy heavy ion collisions -- a scenario without vorticity
• Toward a Unified Understanding of the Dense Matter Equation of State
• Microscopic study of baryon stopping in low-energy heavy-ion collisions within UrQMD model
• Covariant formulation of relativistic quantum molecular dynamics for a system of interacting wave packets
• Constraining the Phase-Transition EoS using the Energy Dependence of Directed Flow