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Test of Lepton Universality Using B+K++ Decays

R. Aaij et al. (LHCb Collaboration)
Phys. Rev. Lett. 113, 151601 – Published 6 October 2014
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Abstract

A measurement of the ratio of the branching fractions of the B+K+μ+μ and B+K+e+e decays is presented using proton-proton collision data, corresponding to an integrated luminosity of 3.0fb1, recorded with the LHCb experiment at center-of-mass energies of 7 and 8 TeV. The value of the ratio of branching fractions for the dilepton invariant mass squared range 1<q2<6GeV2/c4 is measured to be 0.7450.074+0.090(stat)±0.036(syst). This value is the most precise measurement of the ratio of branching fractions to date and is compatible with the standard model prediction within 2.6 standard deviations.

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  • Received 25 June 2014

DOI:https://doi.org/10.1103/PhysRevLett.113.151601

This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Published by the American Physical Society

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A Challenge to Lepton Universality

Published 6 October 2014

The finding that electrons and muons aren’t produced equally in certain particle decays may hint at a crack in the standard model.

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Vol. 113, Iss. 15 — 10 October 2014

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