Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 73: Flavour physics 3
T 73.4: Talk
Wednesday, March 6, 2024, 16:45–17:00, Geb. 30.41: HS 4
Testing of lepton universality with Λb0 → pK−ℓ+ℓ− decays at LHCb — Johannes Albrecht1, Vitalii Lisovskyi2, and •Jannis Speer1 — 1TU Dortmund University, Dortmund, Germany — 2EPFL, Lausanne, Switzerland
Rare decays involving b → s ℓ+ℓ− transitions offer a wide variety of probes for the Standard Model. This includes null tests of fundamental properties of the Standard Model, such as lepton flavour universality (LFU), which states that the couplings of the gauge boson to the three lepton generations are identical.
The LHCb experiment has performed several measurements of LFU in rare b-meson decays, most recently the ratio of branching fractions of the electron and muon mode in the decay channels B+ → K+ ℓ+ℓ− and B0 → K*0 ℓ+ℓ−.
However, LFU can also be tested in rare b-baryon decays, which are subject to partly orthogonal experimental and theoretical uncertainties.
The first measurement of the ratio of branching fractions of the decays Λb0 → pK− e+e− and Λb0 → pK− µ+µ−, RpK−1, was performed by the LHCb Collaboration using proton-proton collision data corresponding to an integrated luminosity of 4.7 fb−1.
The ratio was measured to be RpK−1 = 1.17 +0.18
−0.16 ± 0.07 in the dilepton mass-squared range 0.1 < q2 < 6.0 GeV2/c4 and the pK mass range m(pK) < 2600 MeV/c2.
The updated measurement of RpK−1 seeks to reduce the uncertainties by analysing the full 9 fb−1 dataset of LHCb experiment and implementing new selection techniques.
This contribution presents the current status of the ongoing analysis.
Keywords: LHCb; Rare Decays; LFU; Lepton Flavour Universality; Electroweak Penguins