Single top production via flavour changing neutral currents in the reactions e+e--->t¯c/u is searched for in approximately 411 pb-1 of data collected by ALEPH at centre-of-mass energies in the range between 189 and 202 GeV. In total, 58 events are selected in the data to be compared with 50.3 expected from Standard Model backgrounds. No deviation from the Standard Model expectation is observed. Upper limits at 95% CL on single top production cross sections at /sqrt(s)=189-/202 GeV are derived. A model-dependent limit on the sum of branching ratios /BR(t-->Zc)+BR(t-->Zu)<17% is obtained.
Search for single top production in e+e− collisions at –202 GeV
GREGORIO, ANNA;GIANNINI, GIANROSSANO;
2000-01-01
Abstract
Single top production via flavour changing neutral currents in the reactions e+e--->t¯c/u is searched for in approximately 411 pb-1 of data collected by ALEPH at centre-of-mass energies in the range between 189 and 202 GeV. In total, 58 events are selected in the data to be compared with 50.3 expected from Standard Model backgrounds. No deviation from the Standard Model expectation is observed. Upper limits at 95% CL on single top production cross sections at /sqrt(s)=189-/202 GeV are derived. A model-dependent limit on the sum of branching ratios /BR(t-->Zc)+BR(t-->Zu)<17% is obtained.File in questo prodotto:
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