Polarization of $\Lambda$ ($\bar{\Lambda }$) hyperons along the beam direction in Au+Au collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV

Abstract

The $\Lambda$ ($\bar{\Lambda }$) hyperon polarization along the beam direction has been measured for the first time in Au+Au collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV. The polarization dependence on the hyperons' emission angle relative to the second-order event plane exhibits a sine modulation, indicating a quadrupole pattern of the vorticity component along the beam direction. The polarization is found to increase in more peripheral collisions, and shows no strong transverse momentum ($p_T$) dependence at $p_T>1$ GeV/$c$. The magnitude of the signal is about five times smaller than those predicted by hydrodynamic and multiphase transport models; the observed phase of the emission angle dependence is also opposite to these model predictions. In contrast, blast-wave model calculations reproduce the modulation phase measured in the data and capture the centrality and transverse momentum dependence of the signal once the model is required to reproduce the azimuthal dependence of the Gaussian source radii measured via the Hanbury-Brown and Twiss intensity interferometry technique.

arXiv comment8 pages, 4 figures, Submitted to Phys. Rev. Lett

References in corpus (32)

• Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions
• Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
• Quark Gluon Plasma an Color Glass Condensate at RHIC? The perspective from the BRAHMS experiment
• The PHOBOS Perspective on Discoveries at RHIC
• Collective flow and viscosity in relativistic heavy-ion collisions
• Methods for analyzing anisotropic flow in relativistic nuclear collisions
• Thermal phenomenology of hadrons from 200 AGeV S+S collisions
• Global $\Lambda$ hyperon polarization in nuclear collisions: evidence for the most vortical fluid
• Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at sqrt(S(NN))= 2.76 TeV with the ATLAS Detector at the LHC
• The STAR Time Projection Chamber: A Unique Tool for Studying High Multiplicity Events at RHIC
• Observation and studies of jet quenching in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV
• Globally Polarized Quark-gluon Plasma in Non-central A+A Collisions
• Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Triangularity and Dipole Asymmetry in Heavy Ion Collisions
• Global polarization of $\Lambda$ hyperons in Au+Au collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV
• 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
• Polarization probes of vorticity in heavy ion collisions
• The RHIC Zero Degree Calorimeter
• Collective longitudinal polarization in relativistic heavy-ion collisions at very high energy
• Polarization and Entanglement in Baryon-Antibaryon Pair Production in Electron-Positron Annihilation
• Vortical fluid and $\Lambda$ spin correlations in high-energy heavy-ion collisions
• Probing vorticity structure in heavy-ion collisions by local $\Lambda$ polarization
• Inclusive charged hadron elliptic flow in Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 39 GeV
• Elliptic flow of identified hadrons in Au+Au collisions at $\sqrt{s_{NN}}=$ 7.7--62.4 GeV
• Feed-down effect on $\Lambda$ spin polarization
• The STAR Vertex Position Detector
• Azimuthal angle dependence of the longitudinal spin polarization in relativistic heavy ion collisions
• Vorticity and particle polarization in heavy ion collisions (experimental perspective)
• Polarized secondary particles in unpolarized high energy hadron-hadron collisions?
• Kaon Photoproduction and the $\Lambda$ Decay Parameter ${\alpha }_{-}$

Cited by in corpus (149)

• Polarization and Vorticity in the Quark Gluon Plasma
• Shear-induced spin polarization in heavy-ion collisions
• Local polarization and isothermal local equilibrium in relativistic heavy ion collisions
• Generating spin polarization from vorticity through nonlocal collisions
• Spin-thermal shear coupling in a relativistic fluid
• The ALICE experiment: a journey through QCD
• Relativistic dissipative spin dynamics in the relaxation time approximation
• Relativistic spin hydrodynamics with torsion and linear response theory for spin relaxation
• Spin polarization induced by the hydrodynamic gradients
• From Chiral Kinetic Theory To Relativistic Viscous Spin Hydrodynamics
• Anomalous chiral transports and spin polarization in heavy-ion collisions
• Derivation of the nonlocal collision term in the relativistic Boltzmann equation for massive spin-1/2 particles from quantum field theory
• Dissipative Spin Dynamics in Relativistic Matter
• Global polarization of $\Xi$ and $\Omega$ hyperons in Au+Au collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV
• Local spin polarization in high energy heavy ion collisions
• Reexamination of local spin polarization beyond global equilibrium in relativistic heavy ion collisions
• Weak phases and CP-symmetry tests in sequential decays of entangled double-strange baryons
• A hydrodynamic study of hyperon spin polarization in relativistic heavy ion collisions
• Spin Polarizations in a Covariant Angular-Momentum-Conserved Chiral Transport Model
• Vorticity in low-energy heavy-ion collisions
• Covariant Spin Kinetic Theory I: Collisionless Limit
• Precise Measurements of Decay Parameters and $CP$ Asymmetry with Entangled $\Lambda -\bar{\Lambda }$ Pairs
• Local spin alignment of vector mesons in relativistic heavy-ion collisions
• Foundations and Applications of Quantum Kinetic Theory
• Spin Hall effect in heavy ion collisions
• Improved quark coalescence model for spin alignment and polarization of hadrons
• Ideal spin hydrodynamics from Wigner function approach
• Relativistic Spin Magnetohydrodynamics
• The Present and Future of QCD
• Spin polarization dynamics in the Gubser-expanding background
• Spin and polarization: a new direction in relativistic heavy ion physics
• Analytic solutions of relativistic dissipative spin hydrodynamics with Bjorken expansion
• Relativistic second-order spin hydrodynamics: an entropy-current analysis
• Local and global polarization of $\Lambda$ hyperons across RHIC-BES energies: the roles of spin hall effect, initial condition and baryon diffusion
• Relativistic first-order spin hydrodynamics via the Chapman-Enskog expansion
• Spin alignment of vector mesons by glasma fields
• Vorticity and Spin Polarization in Heavy Ion Collisions: Transport Models
• Vorticity and Spin Polarization --- A Theoretical Perspective
• Hyperon Polarization from the Vortical Fluid in Low Energy Nuclear Collisions
• Canonical and phenomenological formulations of spin hydrodynamics
• Pseudogauge dependence of the spin polarization and of the axial vortical effect
• Pseudo-gauges and relativistic spin hydrodynamics for interacting Dirac and Proca fields
• Spin Polarization Formula for Dirac Fermions at Local Equilibrium
• Quantum kinetic theory for dynamical spin polarization from QED-type interaction
• Polarization phenomenon in heavy-ion collisions
• Quantum Kinetic Theory for Quantum Electrodynamics
• Effect of thermal shear on longitudinal spin polarization in a thermal model
• Spin polarization dynamics in the non-boost-invariant background
• Stability studies of first order spin-hydrodynamic frameworks
• Kubo formulae for first-order spin hydrodynamics
• The causality and stability of relativistic spin-hydrodynamics
• Hyperon polarization along the beam direction relative to the second and third harmonic event planes in isobar collisions at $\sqrt{s_{NN}}$ = 200 GeV
• Dynamics of Hot QCD Matter -- Current Status and Developments
• Analytic solutions of relativistic dissipative spin hydrodynamics with radial expansion in Gubser flow
• Hydrodynamic helicity polarization in relativistic heavy ion collisions
• QCD phase structure under rotation
• Spin alignment of vector mesons by second-order hydrodynamic gradients
• Relativistic hydrodynamics with spin in the presence of electromagnetic fields
• Kinetic theory with spin: From massive to massless fermions
• Spin polarization and correlation of quarks from glasma
• Evolution of $\Lambda$ polarization in the hadronic phase of heavy-ion collisions
• Spin evolution of massive fermion in QED plasma
• Hyperon--anti-hyperon polarization asymmetry in relativistic heavy-ion collisions as an interplay between chiral and helical vortical effects
• A study of $\Lambda$ and $\bar{\Lambda }$ polarization splitting by meson field in PICR hydrodynamic model
• Spin polarization dynamics in the Bjorken-expanding resistive MHD background
• Hybrid approach to perfect and dissipative spin hydrodynamics
• Boost invariant spin hydrodynamics within the first order in derivative expansion
• From Chiral Kinetic Theory To Spin Hydrodynamics
• Lorentz-covariant kinetic theory for massive spin-1/2 particles
• Linear mode analysis from spin transport equation
• Spin waves in spin hydrodynamics
• Anomalous magnetohydrodynamics with temperature-dependent electric conductivity and application to the global polarization
• Local Spin Polarization in 200 GeV Au+Au and 2.76 TeV Pb+Pb Collisions
• Spin dynamics with realistic hydrodynamic background for relativistic heavy-ion collisions
• Generalized thermodynamic relations for perfect spin hydrodynamics
• Spin polarization induced by magnetic field and the relativistic Barnett effect
• Hyperon polarization and its relation with directed flow in high-energy nuclear collisions
• Vorticity and $\Lambda$ polarization in the microscopic transport model PACIAE
• Strongly Interacting Matter Under Rotation: An Introduction
• Cross effects in spin hydrodynamics: A revisit Entropy analysis and statistical operator
• The linear mode analysis and spin relaxation
• Collisional corrections to spin polarization from quantum kinetic theory using Chapman-Enskog expansion
• Anomalous gravitomagnetic moment and non-universality of the axial vortical effect at finite temperature
• Global polarization in heavy-ion collisions based on axial vortical effect
• Global $\Lambda$ polarization in heavy-ion collisions at energies 2.4--7.7 GeV: Effect of Meson-Field Interaction
• Linear response hydrodynamics of a relativistic dissipative fluid with spin
• Effects of a parallel electromagnetic field in three-flavor Nambu--Jona-Lasinio model
• Berry phase in the phase space worldline representation: the axial anomaly and classical kinetic theory
• Nucleon spin polarization in intermediate-energy heavy-ion collisions
• Vorticity and Polarization in Heavy Ion Collisions: Hydrodynamic Models
• Does the spin tensor play any role in non-gravitational physics?
• Spin dynamics in intermediate-energy heavy-ion collisions with rigorous angular momentum conservation
• Shear-induced anomalous transport and charge asymmetry of triangular flow in heavy-ion collisions
• Transverse and longitudinal spin alignment from color fields in heavy ion collisions
• Observation of $\Lambda$ hyperon local polarization in pPb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV
• Collective dynamics of polarized spin-half fermions in relativistic heavy-ion collisions
• Dilepton Helical Production in a Vortical Quark-Gluon Plasma
• Signatures of the vortical quark-gluon plasma in hadron yields
• Propagation of spin channel waves
• Recent developments in chiral and spin polarization effects in heavy-ion collisions
• Mean free path of photons in relativistic heavy ion collisions
• Macroscopic transports in a rotational system with an electromagnetic field
• Revisiting angular momentum conservation in transport simulations of intermediate-energy heavy-ion collisions
• Quarkonium Polarization in Medium from Open Quantum Systems and Chromomagnetic Correlators
• Spin Polarization of $\Lambda$ hyperons from Dissipative Spin Hydrodynamics
• De Haas - van Alphen Effect under Rotation
• Polarization of spin-1/2 particles with effective spacetime dependent masses
• $J/\psi$ and $\psi$(2S) polarization in proton-proton collisions at energies available at the CERN Large Hadron Collider using PYTHIA8
• Local equilibrium and Lambda polarization in high energy heavy ion collisions
• Scalar boson emission from a magnetized relativistic plasma
• Spin alignment of quarkonia in vortical quark-gluon plasma
• Equal-time kinetic equations in a rotational field
• Second-order spin hydrodynamics from Zubarev's nonequilibrium statistical operator formalism
• Estimating Longitudinal Polarization of $\Lambda$ and $\bar{\Lambda }$ Hyperons at Relativistic Energies using Hydrodynamic and Transport models
• Anisotropic linear waves and breakdown of the momentum expansion in spin magnetohydrodynamics
• Spin Effects In Heavy Ion Collisions at High Energies
• Application range of perfect spin hydrodynamics
• First-order spin magnetohydrodynamics
• Gyromagnetic bifurcation in a levitated ferromagnetic particle
• Probing properties of nuclear spin-orbit interaction with nucleon spin polarization in intermediate-energy heavy-ion collisions
• Spin polarization and alignment in heavy-ion collisions
• Hybrid framework of Fermi-Dirac spin hydrodynamics
• Local spin polarizations in relativistic heavy ion collisions
• Polarization in heavy ion collisions: a theoretical review
• Helicity polarization in relativistic heavy ion collisions
• On the non-uniqueness of the energy-momentum and spin currents
• In-medium Electromagnetic Form Factors and Spin Polarizations
• Anomalous spin polarization from turbulent color fields
• Recent progress on global and local polarization of hyperons in heavy-ion collisions
• Impact of spin polarization on transport and thermodynamic coefficients
• Dissipative effects on the propagation of spin modes
• Thermal response of the Nieh-Yan term
• Dirac fermions under imaginary rotation
• Study of spin polarization dependence on rapidity, transverse momentum, and azimuthal angle
• Theoretical aspects of relativistic spin hydrodynamics coupled with electromagnetic fields
• Dynamical induced quark spin polarization by magnetic field at the early stage of heavy-ion collisions
• Guiding center hydrodynamics with spin
• Exact Wigner function for chiral spirals
• Perfect spinfluid: A divergence-type approach
• On the local thermodynamic relations in relativistic spin hydrodynamics
• Probing early-time longitudinal dynamics with the $\Lambda$ hyperon's spin polarization in relativistic heavy-ion collisions
• Tensor spin polarization induced by curved freeze-out hypersurface
• An improved formula for Wigner function and spin polarization in a decoupling relativistic fluid at local thermodynamic equilibrium
• Nonlinear causality and stability of perfect spin hydrodynamics and its nonperturbative character
• Heavy quark polarization anisotropy as a novel probe of fireball geometry
• Minimal-Length Corrections to Hyperon Polarization in Rotating Quark Gluon Plasma
• Is nucleon spin thermalized in intermediate-energy heavy-ion collisions?
• Global $\Lambda$ hyperon polarization in low-energy heavy ion collisions -- a scenario without vorticity
• Quantum fluctuation in rotation velocity of a levitated magnetic particle