Title Measurement of the ratio $B(t\rightarrow Wb)/B(t\rightarrow Wq)$ in pp collisions at $\sqrt{s}$=8 TeV Author Khachatryan, V. Sirunyan, A. M. Tumasyan, A. Alderweireldt, S. Bansal, M. Bansal, S. Cornelis, T. de Wolf, E.A. Janssen, X. Knutsson, A. Luyckx, S. Roland, B. Rougny, R. van de Klundert, M. van Haevermaet, H. Van Mechelen, P. Van Remortel, N. Van Spilbeeck, A. et al. Faculty/Department Faculty of Sciences. Physics Publication type article Publication 2014 Amsterdam , 2014 Subject Physics Source (journal) Physics letters: B. - Amsterdam, 1967, currens Volume/pages 736(2014) , p. 33-57 ISSN 0370-2693 ISI 000341487800007 Carrier E Target language English (eng) Full text (Publishers DOI) Affiliation University of Antwerp Abstract The ratio of the top-quark branching fractions R = B(t --> Wb)/B(t --> Wq), where the denominator includes the sum over all down-type quarks (q = b, s, d), is measured in the t (t) over bar dilepton final state with proton-proton collision data at root s = 8 TeV from an integrated luminosity of 19.7 fb(-1), collected with the CMS detector. In order to quantify the purity of the signal sample, the cross section is measured by fitting the observed jet multiplicity, thereby constraining the signal and background contributions. By counting the number of b jets per event, an unconstrained value of R = 1.014 +/- 0.003 (stat.) +/- 0.032 (syst.) is measured, in a good agreement with current precision measurements in electroweak and flavour sectors. A lower limit R > 0.955 at the 95% confidence level is obtained after requiring R <= 1, and a lower limit on the Cabibbo-Kobayashi-Maskawa matrix element |V-tb| > 0.975 is set at 95% confidence level. The result is combined with a previous CMS measurement of the t-channel single-top-quark cross section to determine the top-quark total decay width, Gamma(t) = 1.36 +/- 0.02 (stat.)(-0.11)(+0.14) (syst.) GeV. (C) 2014 The Authors. Published by Elsevier B.V. Full text (open access) https://repository.uantwerpen.be/docman/irua/3b8a6b/8523.pdf E-info http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000341487800007&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000341487800007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000341487800007&DestLinkType=CitingArticles&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 Handle