The decay of beauty quark to τ lepton and neutrino in the DELPHI experiment at LEP
1998 (English)Doctoral thesis, comprehensive summary (Other academic)
Using 3.5 millions hadronic Z0 events collected during the LEP1 period at the DELPHI detector, the decays of b quarks to tvt have been searched for in both the inclusive and exclusive decay modes. The analysis technique is based on b-tagging, missing energy and identifications of t products. The inclusive semileptonic branching ratio was found to be BR(b --> tntX)= 2.52 ± 0.23(stat.) ± ( 0.49(syst.)%, a result that is in good agreement with the Standard Model prediction and with previous measurements by LEP experiments. No signal for the exclusive leptonic decay B- --> tn-t was observed in the data. The upper limit on the branching ratio $BR(B- --> t-nt) < 1.1x10-3 GeV-1 is set at 90% confidence level. As a consequence of this result a limit on tanb /MH± < 0.46 is also derived in the framework of any type II Higgs doublet model at 90 % confidence level.
Place, publisher, year, edition, pages
Stockholm: Fysikum , 1998. , 61 p.
Research subject Physics
IdentifiersURN: urn:nbn:se:su:diva-45876ISBN: 91-7153-759-7OAI: oai:DiVA.org:su-45876DiVA: diva2:370127
1998-06-02, Föreläsningssalen, Fysikum, Vanadisvägen 9, Stockholm, 10:30 (English)
Hansen, J.D., Dr.
Härtill fyra uppsatser.2010-11-152010-11-152010-11-15Bibliographically approved