Anisotropy of dilepton emission from nucleon-nucleon interactions

We study the angular characteristics of e+e− pairs produced in nucleon-nucleon interactions at intermediate energies on the basis of a one-boson-exchange model fitted to elastic NN scattering. Due to spin and angular momentum constraints, the dilepton anisotropy is found to be sensitive to the contribution of different sources. The anisotropy from NN-bremsstrahlung and delta resonance is calculated and compared to the Dalitz decay from pseudo-scalar and vector mesons.