https://doi.org/10.1140/epjc/s10052-022-10002-y
Regular Article - Theoretical Physics
Hyperon–anti-hyperon polarization asymmetry in relativistic heavy-ion collisions as an interplay between chiral and helical vortical effects
1
Department of Physics, West University of Timioara, Bd. Vasile Pârvan 4, 300223, Timioara, Romania
2
Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität, Max-von-Laue-Strasse 1, 60438, Frankfurt am Main, Germany
3
Institut Denis Poisson UMR 7013, Université de Tours, 37200, Tours, France
4
Pacific Quantum Center, Far Eastern Federal University, 690950, Vladivostok, Russia
Received:
13
September
2021
Accepted:
6
January
2022
Published online:
22
January
2022
We argue that the enhancement in the spin polarization of anti-hyperons compared to the polarization of the hyperons in noncentral relativistic heavy-ion collisions arises as a result of an interplay between the chiral and helical vortical effects. The chiral vortical effect generates the axial current of quarks along the vorticity axis while the recently found helical vortical effect generates the helicity flow – the projection of the quark’s polarization vector onto its momentum – along the same axis. For massless fermions, the helical charge corresponds to a difference in the contributions of particles and anti-particles to the axial charge. Assuming that the spin of light quarks transfers to the strange quarks via the vector kaon states (“the spin-vector dominance”), we are able to describe the ratio of the (anti)hyperon spin polarizations, obtained by the STAR group, without fitting parameters. We also argue that the helical vortical effect dominates over the chiral vortical effect and the chiral magnetic effect in the generation of the electric current.
© The Author(s) 2022
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