Evidence of spin-orbital angular momentum interactions in relativistic heavy-ion collisions

Abstract

The first evidence of spin alignment of vector mesons ($K^{\ast 0}$ and $\varphi$) in heavy-ion collisions at the Large Hadron Collider (LHC) is reported. The spin density matrix element ${\rho }_{00}$ is measured at midrapidity ($|y|<$ 0.5) in Pb-Pb collisions at a center-of-mass energy ($\sqrt{s_{\mathrm{NN}}}$) of 2.76 TeV with the ALICE detector. ${\rho }_{00}$ values are found to be less than 1/3 (1/3 implies no spin alignment) at low transverse momentum ($p_{\mathrm{T}}<$ 2 GeV/$c$) for $K^{\ast 0}$ and $\varphi$ at a level of 3$\sigma$ and 2$\sigma$, respectively. No significant spin alignment is observed for the $K_S^0$ meson (spin = 0) in Pb-Pb collisions and for the vector mesons in $pp$ collisions. The measured spin alignment is unexpectedly large but qualitatively consistent with the expectation from models which attribute it to a polarization of quarks in the presence of angular momentum in heavy-ion collisions and a subsequent hadronization by the process of recombination.

19 pages, 3 captioned figures + 1 figure and 1 table in appendix, authors from page 11, published version, figures at http://alice-publications.web.cern.ch/node/5657

References in corpus (7)

• An Introduction to PYTHIA 8.2
• Angular momentum conservation in heavy ion collisions at very high energy
• K*(892)${}^0$ and $\Phi$(1020) production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Elliptic flow of identified hadrons in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Global polarization of $\Lambda$ and $\overline{\Lambda }$ hyperons in Pb-Pb collisions at the LHC
• What can we learn from global spin alignment of $\varphi$ meson in heavy-ion collisions?
• Global polarization of QGP in non-central heavy ion collisions at high energies

Cited by in corpus (98)

• Generating spin polarization from vorticity through nonlocal collisions
• The ALICE experiment: a journey through QCD
• Pattern of Global Spin Alignment of $\varphi$ and $K^{\ast 0}$ mesons in Heavy-Ion Collisions
• Relativistic dissipative spin dynamics in the relaxation time approximation
• Properties of the QCD Matter -- An Experimental Review of Selected Results from RHIC BES Program
• Relativistic spin hydrodynamics with torsion and linear response theory for spin relaxation
• Dissipative Spin Dynamics in Relativistic Matter
• Relativistic second-order dissipative spin hydrodynamics from the method of moments
• Local spin alignment of vector mesons in relativistic heavy-ion collisions
• Spin Hall effect in heavy ion collisions
• Improved quark coalescence model for spin alignment and polarization of hadrons
• Relativistic Spin Magnetohydrodynamics
• The Present and Future of QCD
• Measurement of the J/$\psi$ polarization with respect to the event plane in Pb-Pb collisions at the LHC
• Relativistic Viscous Hydrodynamics with Angular Momentum
• Spin polarization dynamics in the Gubser-expanding background
• Relativistic second-order spin hydrodynamics: an entropy-current analysis
• Spin alignment of vector mesons by glasma fields
• Local Equilibrium Spin Distribution From Detailed Balance
• Gyrohydrodynamics: Relativistic spinful fluid with strong vorticity
• Little-Bang and Femto-Nova in Nucleus-Nucleus Collisions
• Canonical and phenomenological formulations of spin hydrodynamics
• Pseudo-gauges and relativistic spin hydrodynamics for interacting Dirac and Proca fields
• Quantum kinetic theory for dynamical spin polarization from QED-type interaction
• Polarization phenomenon in heavy-ion collisions
• Effect of thermal shear on longitudinal spin polarization in a thermal model
• Stability studies of first order spin-hydrodynamic frameworks
• Spin polarization dynamics in the non-boost-invariant background
• New Developments in Relativistic Fluid Dynamics with spin
• Global spin alignment of vector mesons and strong force fields in heavy- ion collisions
• Lorentz-covariant nonlocal collision term for spin-1/2 particles
• Properties of the QCD Matter: A Review of Selected Results from the ALICE Experiment
• Dynamics of Hot QCD Matter -- Current Status and Developments
• Damping of spin waves
• Spin alignment of vector mesons by second-order hydrodynamic gradients
• Relativistic hydrodynamics with spin in the presence of electromagnetic fields
• Vector meson's spin alignments in high energy reactions
• Spin polarization and correlation of quarks from glasma
• Spin alignment measurement of vector mesons produced in high energy collisions
• Spin evolution of massive fermion in QED plasma
• Hybrid approach to perfect and dissipative spin hydrodynamics
• Boost invariant spin hydrodynamics within the first order in derivative expansion
• Spin waves in spin hydrodynamics
• Impact of globally spin-aligned vector mesons on the search for the chiral magnetic effect in heavy-ion collisions
• Resummed spin hydrodynamics from quantum kinetic theory
• Spin dynamics with realistic hydrodynamic background for relativistic heavy-ion collisions
• Generalized thermodynamic relations for perfect spin hydrodynamics
• The Spin Alignment of Vector Mesons in High Energy pp Collisions
• Spin alignment of vector mesons from quark dynamics in a rotating medium
• Spin polarization induced by magnetic field and the relativistic Barnett effect
• Strongly Interacting Matter Under Rotation: An Introduction
• Collisional corrections to spin polarization from quantum kinetic theory using Chapman-Enskog expansion
• The effect of hadronic scatterings on the measurement of vector meson spin alignments in heavy-ion collisions
• Rescattering effect on the measurement of K* spin alignment in heavy-ion collisions
• Effect of Coriolis Force on Electrical Conductivity Tensor for Rotating Hadron Resonance Gas
• Inclusive and semi-inclusive production of spin-3/2 hadrons in $e^{+}{e}^{-}$ annihilation
• Production rate and ellipticity of lepton pairs from a rotating hot and dense QCD medium
• Transverse and longitudinal spin alignment from color fields in heavy ion collisions
• The spin alignment of vector mesons with light front quarks
• Signatures of the vortical quark-gluon plasma in hadron yields
• Mean free path of photons in relativistic heavy ion collisions
• Heavy-quark dominance and fine structure of excited heavy baryons ${\Sigma }_Q$, ${\Xi }_Q^{\prime }$ and ${\Omega }_Q$
• Spin Density Matrix for ${\Omega }^{-}$ and its Polarization Alignment in $\psi (3686)\to {\Omega }^{-}{\bar{\Omega }}^{+}$
• Quarkonium Polarization in Medium from Open Quantum Systems and Chromomagnetic Correlators
• Zilch Vortical Effect for Fermions
• Polarization of spin-1/2 particles with effective spacetime dependent masses
• Spin-Vorticity Coupling for Massive Vector Mesons
• Chiral and deconfinement transitions in spin-polarized quark matter
• Spin alignment of $K^{\ast }$ induced by strange-baryon density inhomogeneity
• Spin Effects In Heavy Ion Collisions at High Energies
• Application range of perfect spin hydrodynamics
• Effect of Coriolis Force on Diffusion of D Meson
• Gyromagnetic bifurcation in a levitated ferromagnetic particle
• Spin polarization and alignment in heavy-ion collisions
• Velocity-like maximum polarization: irreversibility and quantum measurements
• Semi-Classical Spin Hydrodynamics in Flat and Curved Spacetime: Covariance, Linear Waves, and Bjorken Background
• Left-right splitting of elliptic flow due to directed flow in heavy ion collisions
• Hybrid framework of Fermi-Dirac spin hydrodynamics
• Spin polarization from nucleon-nucleon scatterings in intermediate-energy heavy-ion collisions
• Sphaleron Transition Rates and the Chiral Magnetic Effect
• Helicity polarization in relativistic heavy ion collisions
• Shear Viscosity and Electrical Conductivity of Rotating Nuclear Medium in Hadron Resonance Gas and Nambu-Jona Lasinio Models
• Anomalous spin polarization from turbulent color fields
• Shear viscosity and electrical conductivity of rotating quark matter in Nambu--Jona-Lasinio Model
• Thermal response of the Nieh-Yan term
• Dissipative effects on the propagation of spin modes
• Impact of spin polarization on transport and thermodynamic coefficients
• Study of spin polarization dependence on rapidity, transverse momentum, and azimuthal angle
• Nonlinear causality and stability of perfect spin hydrodynamics and its nonperturbative character
• Dissociation-driven quarkonium spin alignment in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Heavy quark polarization anisotropy as a novel probe of fireball geometry
• Rotating synchrotron radiation: Photon emission from magnetized and rotating quark-gluon plasma
• Exact Wigner function for chiral spirals
• Practical considerations for the effect of finite coverage on the azimuthal dependence of global spin alignment
• Theoretical aspects of relativistic spin hydrodynamics coupled with electromagnetic fields
• Perfect spinfluid: A divergence-type approach
• Guiding center hydrodynamics with spin
• Quantum fluctuation in rotation velocity of a levitated magnetic particle