Compositeness limits from E+ E- annihilation revisited

Measurements of lepton pair production cross sections by experiments at the SLAC, DESY, and KEK e + e #75 colliders PEP, PETRA, and TRISTAN are reinvestigated in terms of new contact interactions. For maximum sensitivity, a combined analysis of previous measurements and of different leptonic final states is performed. Possible deviations from the standard model are parametrized by the variable ∈ = ±Λ #752 which provides a more sensitive test for additional contact interactions than the traditionally quoted lower limits on the compositeness scale Λ