Leptonic-Decay Distributions for Heavy-Lepton Pairs Produced by Colliding Beams

We present a general differential cross section, in the colliding-beam rest frame, for μe-pair production by leptonic decays of a heavy spin-{} lepton pair, themselves assumed to be produced via one-quantum annihilation. Our results hold for general V, A, S, T, P couplings and depend neither on the μe-universality assumption nor on the absence or presence of neutral-current effects. We also present distributions relevant to the events reported by a Lawrence Berkeley Laboratory-Stanford Linear Accelerator Center group.