Probing vortical structures in heavy-ion collisions at RHIC-BES energies through helicity polarization
Cong Yi, Xiang-Yu Wu, Di-Lun Yang, Jian-Hua Gao, Shi Pu, Guang-You Qin
Abstract
We investigate the azimuthal angle dependent local hydrodynamic helicity polarization of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi mathvariant="normal">Λ</a:mi></a:math> hyperons, defined as the projection of the spin polarization vector along the directions of particle momenta, at BNL Relativistic Heavy Ion Collider beam energy scan energies by utilizing the relativistic (<c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mn>3</c:mn><c:mo>+</c:mo><c:mn>1</c:mn></c:mrow></c:math>)D CLVisc hydrodynamics framework with SMASH initial conditions. As opposed to local spin polarization at high energy collisions, our hydrodynamic simulations demonstrate that the azimuthal angle dependent helicity polarization induced by the kinetic vorticity dominates over other contributions at intermediate and low collision energies. Our findings provide an opportunity to probe the fine structure of local kinetic vorticity as a function of azimuthal angle at intermediate and low collision energies by mapping our predictions to the future measurements in experiments. Published by the American Physical Society 2024