https://doi.org/10.1140/epjc/s10052-015-3844-4
Regular Article - Theoretical Physics
The top quark right coupling in the tbW-vertex
1
Facultad de Ciencias, Instituto de Física, Universidad de la República, Iguá 4225, Montevideo, 11600, Uruguay
2
Departament de Física Teòrica, Universitat de València, and Instituto de Física Corpuscular (IFIC), Centro Mixto Universitat de València-CSIC, Burjassot, 46100, València, Spain
* e-mail: vidal@uv.es
Received:
14
October
2015
Accepted:
11
December
2015
Published online:
26
December
2015
The most general parametrization of the tbW vertex includes a right coupling that is zero at tree level in the standard model. This quantity may be measured at the Large Hadron Collider where the physics of the top decay is currently investigated. This coupling is present in new physics models at tree level and/or through radiative corrections, so its measurement can be sensitive to non-standard physics. In this paper we compute the leading electroweak and QCD contributions to the top coupling in the standard model. This value is the starting point in order to separate the standard model effects and, then, search for new physics. We also propose observables that can be addressed at the LHC in order to measure this coupling. These observables are defined in such a way that they do not receive tree level contributions from the standard model and are directly proportional to the right coupling. Bounds on new physics models can be obtained through the measurements of these observables.
© The Author(s), 2015