First Observation of Photon-Photon Interactions at DORIS

摘要

With a forward tagging system and the BONANZA detector we observed 24 e exp + e exp - implies e exp + e exp - e exp + e exp - events but no e exp + e exp - implies e exp + e exp - + hadrons. We present an upper limit for the partial width of 11.5 keV (95 % CL) which is evidence against the Han-Nambu quark model. (Atomindex citation 10:447395)