@article{a20eedce482949e2a77ee65fe2f4a063,

title = "Test of lepton universality with Λb0→pK− ℓ+ ℓ− decays",

abstract = "The ratio of branching fractions of the decays Λb0 → pK−e+e− and Λb0 → pK−μ+μ−,RpK−1, is measured for the first time using proton-proton collision data corresponding to an integrated luminosity of 4.7 fb−1 recorded with the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV. In the dilepton mass-squared range 0.1 < q2< 6.0 GeV2/c4 and the pK− mass range m(pK−) < 2600 MeV/c2, the ratio of branching fractions is measured to be RpK−1=1.17−0.16+0.18±0.07, where the first uncertainty is statistical and the second systematic. This is the first test of lepton universality with b baryons and the first observation of the decay Λb0 → pK−e+e−. [Figure not available: see fulltext.].",

keywords = "B physics, Branching fraction, Flavour Changing Neutral Currents, Hadron- Hadron scattering (experiments), Rare decay",

author = "{The LHCb Collaboration} and R. Aaij and {Abell{\'a}n Beteta}, C. and T. Ackernley and B. Adeva and M. Adinolfi and H. Afsharnia and Aidala, {C. A.} and S. Aiola and Z. Ajaltouni and S. Akar and P. Albicocco and J. Albrecht and F. Alessio and M. Alexander and {Alfonso Albero}, A. and G. Alkhazov and {Alvarez Cartelle}, P. and Alves, {A. A.} and S. Amato and Y. Amhis and L. An and L. Anderlini and G. Andreassi and M. Andreotti and F. Archilli and {Arnau Romeu}, J. and A. Artamonov and M. Artuso and K. Arzymatov and E. Aslanides and M. Atzeni and B. Audurier and S. Bachmann and Back, {J. J.} and S. Baker and V. Balagura and W. Baldini and A. Baranov and Barlow, {R. J.} and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and G. Bassi and V. Batozskaya and B. Batsukh and A. Battig and A. Petrov and S. Strokov and A. Vagner",

note = "Funding Information: 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",

year = "2020",

month = may,

day = "1",

doi = "10.1007/JHEP05(2020)040",

language = "English",

volume = "2020",

journal = "Journal of High Energy Physics",

issn = "1126-6708",

publisher = "Springer Verlag",

number = "5",

}