This work was supported by the US Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A.P. Sloan Foundation; the Research Corporation; the Bundesministerium für Bildung und Forschung, Germany; the Korean Science and Engineering Foundation and the Korean Research Foundation; the Particle Physics and Astronomy Research Council and the Royal Society, UK; the Russian Foundation for Basic Research; the Comisión Interministerial de Ciencia y Tecnología, Spain; in part by the European Community's Human Potential Programme under contract HPRN-CT-2002-00292; and the Academy of Finland.

We present a search for t¯t events with a tau lepton in the final state. The data sample corresponds to an integrated luminosity of 194 pb−1 collected with the CDF II detector from p¯p collisions at a center of mass energy of 1.96 TeV. We observe two events with an expected signal of 1.0 ± 0.2 events and a background of 1.3 ± 0.3 events. We determine a 95% confidence level upper limit on rτ, the ratio of the measured rate of t →τνqtothe expectation, of 5.2.

CDF Collaboration: et al.

arXiv:hep-ex/0510063v2

Peer reviewed