Measurement of B(t→Wb)/B(t→Wq) in top-quark-pair decays using dilepton events and the full CDF Run II data set

• Published in: Physical review letters 2014-06, Vol.112 (22), p.221801-221801, Article 221801
• Main Authors: Aaltonen, T, Amerio, S, Amidei, D, Anastassov, A, Annovi, A, Antos, J, Apollinari, G, Appel, J A, Arisawa, T, Artikov, A, Asaadi, J, Ashmanskas, W, Auerbach, B, Aurisano, A, Azfar, F, Badgett, W, Bae, T, Barbaro-Galtieri, A, Barnes, V E, Barnett, B A, Barria, P, Bartos, P, Bauce, M, Bedeschi, F, Behari, S, Bellettini, G, Bellinger, J, Benjamin, D, Beretvas, A, Bhatti, A, Bland, K R, Blumenfeld, B, Bocci, A, Bodek, A, Bortoletto, D, Boudreau, J, Boveia, A, Brigliadori, L, Bromberg, C, Brucken, E, Budagov, J, Budd, H S, Burkett, K, Busetto, G, Bussey, P, Butti, P, Buzatu, A, Calamba, A, Camarda, S, Campanelli, M, Canelli, F, Carls, B, Carlsmith, D, Carosi, R, Carrillo, S, Casal, B, Casarsa, M, Castro, A, Catastini, P, Cauz, D, Cavaliere, V, Cavalli-Sforza, M, Cerri, A, Cerrito, L, Chen, Y C, Chertok, M, Chiarelli, G, Chlachidze, G, Cho, K, Chokheli, D, Clark, A, Clarke, C, Convery, M E, Conway, J, Corbo, M, Cordelli, M, Cox, C A, Cox, D J, Cremonesi, M, Cruz, D, Cuevas, J, Culbertson, R, d'Ascenzo, N, Datta, M, de Barbaro, P, Demortier, L, Deninno, M, D'Errico, M, Devoto, F, Di Canto, A, Di Ruzza, B, Dittmann, J R, Donati, S, D'Onofrio, M, Dorigo, M, Driutti, A, Ebina, K, Edgar, R, Elagin, A, Erbacher, R
• Format: Article
• Language: English
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.112.221801

We present a measurement of the ratio of the top-quark branching fractions R=B(t→Wb)/B(t→Wq), where q represents any quark flavor, in events with two charged leptons, imbalance in total transverse energy, and at least two jets. The measurement uses proton-antiproton collision data at center-of-mass energy 1.96 TeV, corresponding to an integrated luminosity of 8.7  fb^{-1} collected with the Collider Detector at Fermilab during Run II of the Tevatron. We measure R to be 0.87±0.07, and extract the magnitude of the top-bottom quark coupling to be |V_{tb}|=0.93±0.04, assuming three generations of quarks. Under these assumptions, a lower limit of |V_{tb}|>0.85(0.87) at 95% (90%) credibility level is set.