Anisotropy of dilepton emission from nuclear collisions

Attention is paid to studying the angular characteristics of e+e− pairs created in collisions with nuclear targets at intermediate and relativistic energies. Arising due to general spin and angular momentum constraints, the dilepton anisotropy seems to be quite sensitive to the contribution of different sources and may be used for disentangling these sources (or models) as well as an additional signature of aossible chiral symmetry restoration and phase transition of hadrons into the quark-gluon plasma. An anisotropy estimate for some dilepton sources is given and its relevance to the problems mentioned is discussed.