Has the Substructure of Quarks and Leptons Been Found also by the H1 and ZEUS Detectors at HERA?

摘要

The significant excess of events recently found by the H1 and ZEUSCollaborations at HERA in the deep-inelastic e^+ p scattering for highmomentum-transfers squared Q^2>15000 GeV^2 over the expectation of the standardmodel can be explained by either one of the following possible consequences ofthe substructure of quarks and leptons: 1) production of leptoquarks (Phi), 2)exchange of an excited Z boson (Z'), 3) intrinsic form factors of quarks (orleptons), 4) intrinsic anomalous magnetic moments of quarks, 5) production ofexcited quarks (q^*), and 6) that of excited positrons (e^*+). The masses ofthese new particles are estimated to be m(Phi) = 280-440 GeV, m(Z') = 210-250GeV, m(q^*) = 120-140 GeV, and m(e^*+) = 300-370 GeV, although thepossibilities 2) and 5) are excluded by the currently available experimentalconstraints.