Abstract:
We show that the process pp (pp)++X is a powerful test to distinguish between gauged integer-charged-quark models (ICQMs) and fractionally-charged- quark models (FCQMs). We study the ratio of the two-photon production cross section to the lepton-pair production cross section. Below color threshold the ICQM value for this ratio ranges from 30 to 130 in pp collisions (and 1035 in pp collisions) in the kinematic range of the CERN ISR experiment, whereas the FCQM value is 1.6. The single experimental result available so far appears to disfavor the ICQM. © 1986 The American Physical Society.