Fig.(4) The lepton pair production differential cross sections (solid lines) for t = –0.2GeV², Q² = 5GeV² integrated over θ = [π/4; 3 π/4], as a function of φ, for s = 107GeV² (a) s = 105 GeV² (b) with μ_F² = 5GeV². We also display the Compton (dotted), Bethe-Heitler (dash-dotted) and Interference (dashed) contributions.