Vortex rings from high energy central <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi><mml:mo>+</mml:mo><mml:mi>A</mml:mi></mml:mrow></mml:math> collisions
M. A. Lisa, João Guilherme Prado Barbon, D. D. Chinellato, Willian Matioli Serenone, Chun Shen, J. Takahashi, Giorgio Torrieri
Abstract
Relativistic $p+A$ collisions may produce droplets of quark-gluon plasma (QGP) that quickly develop a toroidal vortex structure similar to that of an expanding smoke ring. We present viscous relativistic hydrodynamic calculations of ultracentral $p+A$ collisions and develop an experimental observable to probe the structure, correlating the polarization and momentum of hyperons emitted from the collision. This effect is robust against changes in the definition of vorticity used to calculate the polarization. Experiments at the Brookhaven National Laboratory Relativistic Heavy Ion Collider and the CERN Large Hadron Collider may test the existence and strength of the vortex toroids, bringing new evidence to bear on the question of collectivity in the smallest QGP droplets.