Λ polarization in peripheral heavy ion collisions

We predict the polarization of Lambda and (Lambda) over bar 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 Lambda polarization detectable.