https://doi.org/10.1140/epjc/s10052-012-2048-4
Regular Article - Theoretical Physics
Model-independent extraction of |V tq | matrix elements from top-quark measurements at hadron colliders
1
Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489, Berlin, Germany
2
Fachbereich C—Experimentelle Elementarteilchenphysik, Bergische Universität Wuppertal, Gaußstr. 20, 42119, Wuppertal, Germany
3
Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, Wolfgang-Gaede-Str. 1, 76131, Karlsruhe, Germany
4
Centre for Cosmology, Particle Physics and Phenomenology (CP3), Université Catholique de Louvain, Chemin du Cyclotron 2, 1348, Louvain-la-Neuve, Belgium
* e-mail: lacker@physik.hu-berlin.de
Received:
6
March
2012
Revised:
15
May
2012
Published online:
22
June
2012
Current methods to extract the quark-mixing matrix element |V
tb
| from single-top-production measurements assume that |V
tb
|≫|V
td
|,|V
ts
|: top quarks decay into b quarks with 100 % branching fraction, s-channel single-top production is always accompanied by a b quark and initial-state contributions from d and s quarks in the t-channel production of single top quarks are neglected. Triggered by a recent measurement of the ratio 
performed by the D0 collaboration, we consider a |V
tb
| extraction method that takes into account non zero d- and s-quark contributions both in production and decay. We propose a strategy that allows to extract consistently and in a model-independent way the quark-mixing matrix elements |V
td
|, |V
ts
|, and |V
tb
| from the measurement of R and from single-top measured event yields. As an illustration, we apply our method to the Tevatron data using a CDF analysis of the measured single-top event yield with two jets in the final state, one of which is identified as a b-quark jet. We constrain the |V
tq
| matrix elements within a four-generation scenario by combining the results with those obtained from direct measurements in flavor physics and determine the preferred range for the top-quark decay width within different scenarios.
© Springer-Verlag / Società Italiana di Fisica, 2012
