Spin alignment of vector mesons in heavy-ion collisions

Abstract

Polarized quarks and antiquarks in high-energy heavy-ion collisions can lead to the spin alignment of vector mesons formed by quark coalescence. Using the relativistic spin Boltzmann equation for vector mesons derived from Kadanoff-Baym equations with an effective quark-meson model for strong interaction and quark coalescence model for hadronizaton, we calculate the spin density matrix element ${\rho }_{00}$ for $\varphi$ mesons and show that anisotropies of local field correlations or fluctuations with respect to the spin quantization direction lead to $\varphi$ meson's spin alignment. We propose that the local correlation or fluctuation of $\varphi$ fields is the dominant mechanism for the observed the $\varphi$ meson's spin alignment and its strength can be extracted from experimental data as functions of collision energies. The calculated transverse momentum dependence of ${\rho }_{00}$ agrees with STAR's data. We further predict the azimuthal angle dependence of ${\rho }_{00}$ which can be tested in future experiments.

ReVTex 4.1, 14 pages, 4 figures. A large part of the paper has been rewritten with the focus on extracting local correlations or fluctuations of phi fields from STAR's data and predictions for dependences of ${\rho }_{00}$ on the transverse momentum and azimuthal angle

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• Transverse and longitudinal spin alignment from color fields in heavy ion collisions
• Spin dynamics in intermediate-energy heavy-ion collisions with rigorous angular momentum conservation
• The spin alignment of vector mesons with light front quarks
• Vector and Tensor Spin Polarization for Vector Bosons at Local Equilibrium
• Quarkonium Polarization in Medium from Open Quantum Systems and Chromomagnetic Correlators
• Chiral phase transition and spin alignment of vector mesons with chiral imbalance in a rotating QCD medium
• $J/\psi$ and $\psi$(2S) polarization in proton-proton collisions at energies available at the CERN Large Hadron Collider using PYTHIA8
• Impact of strong magnetic field, baryon chemical potential, and medium anisotropy on polarization and spin alignment of hadrons
• First measurement of D${}^{\ast +}$ vector spin alignment in Pb$-$Pb collisions at $\sqrt{{\mathbf{s}}_{\mathrm{NN}}}=5.02$ TeV
• Spin alignment of quarkonia in vortical quark-gluon plasma
• Spin alignment of $K^{\ast }$ induced by strange-baryon density inhomogeneity
• Polarized Dissociation and Spin Alignment of Moving Quarkonium in Quark-Gluon Plasma
• Production of $K^{+}{K}^{-}$ Pairs Through Decay of $\varphi$ Meson
• Spin polarization from nucleon-nucleon scatterings in intermediate-energy heavy-ion collisions
• Axial-Vector and Tensor Spin Polarization and Chiral Restoration in Quark Matter
• Practical Considerations for Measuring Global Spin Density Matrix Elements of Vector Mesons in Heavy-Ion Collisions
• Tensor spin polarization induced by curved freeze-out hypersurface
• Spin alignment of Quarkonia: A Possible Probe of Deconfined QCD matter in Pb+Pb Collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Dissociation-driven quarkonium spin alignment in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV