Phenomenology of spin-vorticity non-equilibrium

• Giorgio Torrieri (Campinas State U., Brazil)

Room: B5118 #Abstract: Motivated by recent progress in spin hydrodynamics, we investigate the spin density matrix of baryons and vector mesons, allowing for non-equilibrium between spin and vorticity. We explain how the coalescence of partially polarized quarks, as well as the transfer of angular momentum from vorticity to the spin of the baryon generically create a partially coherent density matrix. We argue that spin-vorticity non-equilibrium has the potential to solve the long-standing puzzles within the phenomenology of spin in heavy-ion collisions, namely the combined understanding of baryon polarization and meson spin alignment, as well as the azimuthal dependence of baryon longitudinal polarization. Since in the case of vector mesons, this degree of coherence can be experimentally ascertained by measuring off-diagonal matrix elements, We suggest that a measurement of azimuthal dependence of off-diagonal matrix elements of the higher spin (vector and tensor) meson,the quarkonium spin density matrix and spin 3/2 baryons can falsify and constrain this picture. #References: [1] Kayman J. Goncalves,R. Ryblewski, G. Torrieri, upcoming work [2] Kayman J. Goncalves,P.H. De Moura and G. Torrieri Phys.Rev.D 108 (2023) 3, 034032 [3] Kayman J. Goncalves,G. Torrieri Phys.Rev.C 105 (2022) 3, 034913