Sprecher
Beschreibung
In light of the coming measurement of local hyperon polarization by the ALICE collaboration in OO runs, we present a prediction for the local Ξ and Λ polarization computed using Trajectum [1], based on Trajectum’s predictions for other OO observables[2]. Trajectum implements the polarization formula computed by Becattini et al. [3] for a Dirac field in a local thermal equilibrium state with rotation. Becattini’s formula includes a shear and a vorticity term that compete to determine the overall sign of the polarization. We find that the values of the shear and bulk viscosity determine which of these terms is larger; the overall sign of the polarization can be flipped by changing the viscosities. We also discuss our findings on the effects the inclusion of a prehydrodynamic stage and of the choice of initial conditions and, which differ substantially from those employed in previous work. Trajectum’s TRENTO-inspired 3+1D initial condition differ significantly from those employed in previous works[4, 5].
[1] Nijs, van der Schee, Gürsoy, Snellings - Phys. Rev. C 103, 054909 (2021)
[2] Giacalone et al. – arXiv:2402.05995 (2024)
[3] Becattini – arXiv:2004.04050 (2020)
[4] Palermo, Gossi, Karpenko, Becattini - EPJC 84, 920 (2024)
[5] Alzhrani, Ryu, Shen - Phys. Rev. C 106, 014905 (2022)