Heidelberg 2022 – scientific programme
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T: Fachverband Teilchenphysik
T 57: Flavour Physics 5
T 57.2: Talk
Wednesday, March 23, 2022, 16:30–16:45, T-H16
Test of lepton universality with Λb → pK l+l− decays at LHCb — Johannes Albrecht, Vitalii Lisovskyi, and •Jannis Speer — Experimentelle Physik 5, TU Dortmund
In recent measurements of b-hadron decays a pattern of consistent tensions with the SM predictions is observed.
This includes decays with b → s l+l− transitions, which play an important role in lepton flavor universality tests such as RK and RK*0.
Complementary to b-meson decays, lepton flavor universality can also be tested in b-baryon decays which come with partly orthogonal experimental uncertainties.
The first measurement of the ratio of branching fractions of the decays Λb → pK e+e− and Λb → pK µ+µ−, RpK−1, was published by the LHCb Collaboration using proton-proton collision data corresponding to 4.7 fb−1.
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 was measured to be RpK−1 = 1.17 +0.18
−0.16 ± 0.077.
The legacy measurement of RpK−1 tries to reduce the uncertainties by analysing the full 9 fb−1 dataset of LHCb experiment and improving the selection.
In this talk the first study of the data recorded in the years 2017 and 2018 is presented. Furthermore the ongoing improvements in the signal selection requirements are discussed.