Lepton and hadron pair production in two-photon reactions

Abstract We have measured the production of charged particle pairs in e + e − initiated two-photon reactions. The observed rates and invariant mass spectra agree with expectations from QED if a resonant π + π − production at the f 0 mass is added. Assuming dominance of the helicity 2 production we obtain the width Γ (f 0 → γγ ) = 2.3 ± 0.5 keV.