Searches for Flavour Changing Neutral Currents and Lepton Flavour Violation at HERA
Abstract
Description
A summary of the recent searches for anomalous single top-quark production and lepton flavour violation in high energy ep collisions is presented. Single top-quark production via an anomalous flavour changing neutral current gamma-u-t coupling would lead to the reaction ep->etX, t->Wb. H1 observed an excess of events above the Standard Model prediction in the leptonic decay channel of the W boson, leading to an isolated lepton, large missing transverse momentum and a jet with large transverse momentum. Five of these events are compatible with single top-quark production, compared to 1.8 events expected from background processes. ZEUS observed no excess above the SM background expectation in the leptonic channel. Neither of the two experiments found a deviation from the SM background expectation in the 3-jet final state, which would result from the hadronic decay of the W boson. Searches for lepton flavour violating interactions of the type ep->mu X and ep->tau X have been performed. No evidence was found for lepton flavour violation and limits were derived on the production of leptoquarks and R_p violating squarks, which could mediate such interactions.
10 pages, 11 figures,2 tables, contributed to proceedings of the 10th International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY02), DESY Hamburg, June 17-23
10 pages, 11 figures,2 tables, contributed to proceedings of the 10th International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY02), DESY Hamburg, June 17-23