Λ polarization in peripheral heavy ion collisions

Abstract

We predict the polarization of Λ and Λ¯ hyperons in peripheral heavy ion collisions at ultrarelativistic energy, based on the assumption of local thermodynamical equilibrium at the freeze-out. The polarization vector is proportional to the curl of the inverse temperature four-vector field and its length, of the order of percents, is maximal for a particle with moderately high momentum lying on the reaction plane. A selective measurement of these particles could make Λ polarization detectable.