Measurement of the Ratio of Branching Fractions B(¯B0→D*+τ−¯ντ)/B(¯B0→D*+μ−¯νμ)

LHCb Collaboration

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

The branching fraction ratio R(D∗)≡B(¯B0→D*+τ−¯ντ)/B(¯B0→D*+μ−¯νμ) is measured using a sample of proton-proton collision data corresponding to 3.0  fb−1 of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ−→μ−¯νμντ. The semitauonic decay is sensitive to contributions from non-standard-model particles that preferentially couple to the third generation of fermions, in particular, Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate ¯B0 decays gives R(D∗)=0.336±0.027(stat)±0.030(syst). This result, which is the first measurement of this quantity at a hadron collider, is 2.1 standard deviations larger than the value expected from lepton universality in the standard model.
Original languageEnglish
Article number111803
Pages (from-to)1-10
Number of pages10
JournalPhysical Review Letters
Issue number11
Early online date9 Sept 2015
Publication statusPublished - 11 Sept 2015


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