Journal of High Energy Physics

, 2019:191 | Cite as

A method to determine |Vcb| at the weak scale in top decays at the LHC

  • P. F. HarrisonEmail author
  • V.E. Vladimirov
Open Access
Regular Article - Experimental Physics


Until now, the Cabibbo Kobayashi Maskawa matrix element, |Vcb|, has always been measured in B decays, i.e. at an energy scale \( {q}_b\sim \frac{m_b}{2} \), far below the weak scale. We consider here the possibility of measuring it close to the weak scale, at qWmW, in top decays at the Large Hadron Collider (LHC). Our proposed method would use data from the LHC experiments in hadronic top decays \( t\to b{W}^{+}\to b\overline{b}c \), tagged by the semileptonic decay of the associated top. We estimate the uncertainty of such a measurement, as a function of present and potential future experimental jet flavour-tagging performances, and conclude that first measurements using the data collected during 2016-2018 could yield a fractional error on |Vcb| of order 7% per experiment. We also give projected performances at higher luminosities, representative of those anticipated at LHC Run 3 and HL-LHC.


B physics Branching fraction Flavor physics Hadron-Hadron scattering (experiments) Top physics 


Open Access

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.


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Copyright information

© The Author(s) 2019

Authors and Affiliations

  1. 1.Department of PhysicsUniversity of WarwickCoventryU.K.

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