The reaction e+e~e+e m. m has been analyzed using 97 pb ' of data taken with the Crystal Ball detector at the DESY e e+ storage ring DORIS II at beam energies around 5.3 GeV. For the first time we have measured the cross section for yy~m. m. for n m invariant masses ranging from threshold to about 2 GeV. We measure an approximately flat cross section of about 10 nb for 8'=m 0 0 (0.8 GeV, which is below 0.6 GeV, in good agreement with a theoretical prediction 'tr n' based on an unitarized Born-term model. At higher invariant masses we observe formation of the ft(1270) resonance and a hint of the fo(975). We deduce the following two-photon widths: I rr(f, (1270)) =3.19+0. 1620 z, keV and I "(fo( 975)) (0.53 keV at 90% CL. The decayangular distributions show the m~system to be dominantly spin 0 for W &0.7 GeV and spin 2, helicity 2 in the f, (1270) region, with helicity 0 contributing at most 22% (90% C.L.).

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We present a study of 43 000 3-jet events from Z° boson decays. Both the measured jet energy distributions and the event orientation are reproduced by second order QCD. An alternative model with scalar gluons fails to describe the data.

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We present a study of the inclusive production of neutral pions and charged particles from 112 000 hadronic Z° decays. The measured inclusive momentum distributions can be reproduced by parion shower Monte Carlo programs and also by an analytical QCD calculation. Comparing our results to e+e" data between ^= 9 and 91 GeV, we find that the evolution of the spectra with center of mass energy is consistent with the QCD predictions.