  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 ultra-central p+A collisions and develop an experimental observable to probe
the structure, correlating the polarization and momentum of hyperons emitted
from the collision. The effect is robust against changes in the definition of
vorticity used to calculate the polarization. Experiments at RHIC and LHC 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.
