title: Measurement of Cabibbo-suppressed tau lepton decays and the determination of |Vus|
creator: Schenk, Stefan
subject: ddc-530
subject: 530 Physics
description: This work presents simultaneous branching fraction measurements of the decay modes tau- --> K- n pi0 nu_tau with n = 0,1,2,3 and tau- --> pi- n pi0 nu_tau with n = 3,4. The analysis is based on a data sample of 427 x 10^6 tau tau pairs recorded with the BABAR detector, which corresponds to an integrated luminosity of 464.4 fb^-1. The measured values are BR(tau --> K nu) = (6.57 +- 0.03 +- 0.11) x 10^-3, BR(tau --> K pi0 nu) = (4.61 +- 0.03 +- 0.11) x 10^-3, BR(tau --> K pi0 pi0 nu) = (5.05 +- 0.17 +- 0.44) x 10^-4, BR(tau --> K pi0 pi0 pi0 nu) = (1.31 +- 0.43 +- 0.40) x 10^-4, BR(tau --> pi pi0 pi0 pi0 nu) = (1.263 +- 0.008 +- 0.078) x 10^-2 and BR(tau --> pi pi0 pi0 pi0 pi0 nu) = (9.6 +- 0.5 +- 1.2) x 10^-4, where the uncertainties are statistical and systematic, respectively. All measurements are compatible with the current world averages whereas the uncertainties are significantly smaller by a factor of up to five. The determination of BR(tau --> pi pi0 pi0 pi0 pi0 nu) is the first measurement of this branching fraction. The measured branching fractions are combined with the current world averages. Using the new averages, an updated determination of |Vus| from hadronic tau decays yields |Vus| = 0.2146 +- 0.0025, which improves previous measurements by 19 %. Its uncertainty is comparable to the one of the current world average from semileptonic kaon decays.
date: 2008
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/8546/1/document1.pdf
identifier: DOI:10.11588/heidok.00008546
identifier: urn:nbn:de:bsz:16-opus-85461
identifier:   Schenk, Stefan  (2008) Measurement of Cabibbo-suppressed tau lepton decays and the determination of |Vus|.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/8546/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng