Global $\Lambda$ polarization in heavy-ion collisions at high baryon density

Abstract

Based on the model of three-fluid dynamics (3FD), the global $\Lambda$ polarization ($P_{\Lambda }$) is calculated in Au+Au collisions at 3 $\le \sqrt{s_{NN}}\le$ 9 GeV, in which high baryon density is achieved. Various contributions to $P_{\Lambda }$ are considered: those from the thermal vorticity, meson field, thermal shear and spin-Hall effect. Feed-down from higher-lying resonances is also taken into account. The results are compared with available data. Special attention is payed to the collision energies of $\sqrt{s_{NN}}=$ 3, 3.2, 3.5, 3.9, and 4.5 GeV, for which a thorough scan of the energy, rapidity, and centrality dependence of $P_{\Lambda }$ is performed. The results for 3 GeV reasonably well reproduce the corresponding STAR data. While the results at $\sqrt{s_{NN}}=$ 3.2, 3.5, 3.9, and 4.5 GeV can be considered as predictions for results of measurements within the STAR fixed-target (STAR-FXT) programthat are expected in the nearest future. It is predicted that a broad maximum of $P_{\Lambda }$ is reached at $\sqrt{s_{NN}}\approx$ 3--3.9 GeV, exact position of which depends on the centrality and width of the midrapidity range of observation. Impact of the meson-field, thermal-shear and spin-Hall-effect contributions to $P_{\Lambda }$ is also studied.

arXiv comment12 pages, 12 figures, minor changes, version published in PRC

References in corpus (51)

• A Multi-Phase Transport Model for Relativistic Heavy Ion Collisions
• Global $\Lambda$ hyperon polarization in nuclear collisions: evidence for the most vortical fluid
• Recent Progress in Quantum Hadrodynamics
• Hadron production in central nucleus-nucleus collisions at chemical freeze-out
• Relativistic distribution function for particles with spin at local thermodynamical equilibrium
• Global polarization of $\Lambda$ hyperons in Au+Au collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV
• Global hyperon polarization at local thermodynamic equilibrium with vorticity, magnetic field and feed-down
• Polarization of massive fermions in a vortical fluid
• Local polarization and isothermal local equilibrium in relativistic heavy ion collisions
• Probing vorticity structure in heavy-ion collisions by local $\Lambda$ polarization
• Spin-thermal shear coupling in a relativistic fluid
• Relativistic Heavy-Ion Collisions within 3-Fluid Hydrodynamics: Hadronic Scenario
• Spin polarization induced by the hydrodynamic gradients
• Solution of the Hyperon Puzzle within a Relativistic Mean-Field Model
• Evolution of transverse flow and effective temperatures in the parton phase from a multi-phase transport model
• Relativistic parameterizations of neutron matter and implications for neutron stars
• Vorticity in low-energy heavy-ion collisions
• Lattice QCD Constraints on the Nuclear Equation of State
• Estimates of hyperon polarization in heavy-ion collisions at collision energies $\sqrt{s_{NN}}=$ 4--40 GeV
• $\Lambda$ and $\bar{\Lambda }$ spin interaction with meson fields generated by the baryon current in high energy nuclear collisions
• Relativistic Mean-Field Models with Scaled Hadron Masses and Couplings: Hyperons and Maximum Neutron Star Mass
• Alternative Scenarios of Relativistic Heavy-Ion Collisions: I. Baryon Stopping
• Local and global polarization of $\Lambda$ hyperons across RHIC-BES energies: the roles of spin hall effect, initial condition and baryon diffusion
• Measurement of global polarization of Λ hyperons in few-GeV heavy-ion collisions
• Global $\Lambda$ polarization in moderately relativistic nuclear collisions
• Dynamical Freeze-out in 3-Fluid Hydrodynamics
• Vorticity in heavy-ion collisions at the JINR Nuclotron-based Ion Collider fAcility
• Hyperon Polarization from the Vortical Fluid in Low Energy Nuclear Collisions
• Alternative Scenarios of Relativistic Heavy-Ion Collisions: II. Particle Production
• Baryon Stopping as a Probe of Deconfinement Onset in Relativistic Heavy-Ion Collisions
• Polarization phenomenon in heavy-ion collisions
• Alternative Scenarios of Relativistic Heavy-Ion Collisions: III. Transverse Momentum Spectra
• Correlation between global polarization, angular momentum and flow in heavy-ion collisions
• Robustness of the Baryon-Stopping Signal for the Onset of Deconfinement in Relativistic Heavy-Ion Collisions
• On freeze-out problem in relativistic hydrodynamics
• Vortex rings in fragmentation regions in heavy-ion collisions at $\sqrt{s_{NN}}=$ 39 GeV
• Vortex rings from high energy central p+A collisions
• Vorticity and Particle Polarization in Relativistic Heavy-Ion Collisions
• Evolution of $\Lambda$ polarization in the hadronic phase of heavy-ion collisions
• A study of $\Lambda$ and $\bar{\Lambda }$ polarization splitting by meson field in PICR hydrodynamic model
• The applicability of hydrodynamics in heavy ion collisions at $\sqrt{s_{\mathrm{NN}}}$= 2.4-7.7 GeV
• Helicity and vorticity in heavy-ion collisions at NICA energies
• Rise and fall of $\Lambda$ and $\bar{\Lambda }$ global polarization in semi-central heavy-ion collisions at HADES, NICA and RHIC energies from the core-corona model
• Hyperon polarization and its relation with directed flow in high-energy nuclear collisions
• Directed flow and global polarization in Au+Au collisions across energies covered by the beam energy scan at RHIC
• Global $\Lambda$ polarization in heavy-ion collisions at energies 2.4--7.7 GeV: Effect of Meson-Field Interaction
• Equilibration and baryon densities attainable in relativistic heavy-ion collisions
• Examination of STAR fixed-target data on directed flow at $\sqrt{s_{NN}}=$ 3 and 4.5 GeV
• Hyperon global polarization in heavy-ion collisions at NICA energies. Feed-down effects and the role of ${\Sigma }^0$ hyperons
• Vortex rings in heavy-ion collisions at energies $\sqrt{s_{NN}}=$ 3--30 GeV and possibility of their observation
• On Ambiguity of Definition of Shear and Spin-Hall Contributions to $\Lambda$ Polarization in Heavy-Ion Collisions

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