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Abstract

We have determined the cross section for gammagammararrpgr+pgr+pgrpgr in a way free of assumptions about the relative contributions fromrgr 0 rgr 0,rgr 02pgr and 4pgr (uncorrelated phase space). We find a sharp onset above threshold and a rather high cross section of about 200 nb aroundW gammagamma=1.5 GeV which consists to about 40% ofrgr 0 rgr 0 production with sizeable contributions fromrgr 02pgr and 4pgr (PS). The total cross section as well as thergr 0 rgr 0 content fall rather fast at higher c.m. energies. Attempts to explain this behaviour in terms of production of known resonances are not successful so far. The angular distributions do not show any significant structure pointing to resonance formation in the 4pgr-system. Only thergr 0-meson is observed in the moment analysis. The decay distributions of thergr 0 for forward produced rhos are fairly consistent with helicity conservation of the produced rhos in accordance with the VDM picture.

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