2007/11/30 by F. Becattini, F. Piccinini, J. R. Rizzo +1 · 3 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #High-Energy Particle Collisions Research #Quantum Chromodynamics and Particle Interactions #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevc.77.024906
published as Phys.Rev.C77:024906,2008 · Minor corrections. Published version in PRC
arxiv created 2008/02/18 · openalex publication_date 2008/02/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The effects of angular momentum conservation in peripheral heavy ion collisions at very high energy are investigated. It is shown that the initial angular momentum of the quark-gluon plasma should enhance the azimuthal anisotropy of particle spectra (elliptic flow) with respect to the usual picture where only the initial geometrical eccentricity of the nuclear overlap region is responsible for the anisotropy. In hydrodynamical terms, the initial angular momentum entails a nontrivial dependence of the initial longitudinal flow velocity on the transverse coordinates. This gives rise to a nonvanishing vorticity in the equations of motion, which enhances the expansion rate of the supposedly created fluid compensating for the possible quenching effect of viscosity. A distinctive signature of the vorticity in the plasma is the generation of an average polarization of the emitted hadrons, for which we provide analytical expressions. These phenomena might be better observed at LHC, where the initial angular momentum density will be larger and where we envisage an increase of the elliptic flow coefficient v2 with respect to RHIC energies.