Dortmund 2021 – wissenschaftliches Programm
T 7.7: Vortrag
Montag, 15. März 2021, 17:30–17:45, Tg
Testing Lepton Flavour Universality with Bs→φℓ+ℓ− decays using LHCb data — Christoph Langenbruch, Stefan Schael, •Sebastian Schmitt, and Eluned Smith — I. Phys. Inst. B RWTH Aachen
In the Standard Model of Particle Physics (SM), b → s ℓ+ℓ− transitions are forbidden at tree-level and may only occur at the loop-level. The branching fractions of these so-called Flavour Changing Neutral Currents (FCNCs) can thus be significantly affected by New Physics (NP) beyond the SM. While in the SM, the coupling of the electro-weak gauge-bosons is Lepton Flavour Universal (LFU), this universality can be broken in NP scenarios. The ratios RH, defined as the ratios of the branching fractions B(B → H µ+µ−) and B(B → H e+e−), constitute precise tests of the SM. Recent measurements of RK and RK∗ 0 show tensions with the SM of 2.1 to 2.5 standard deviations (σ), complementary RH measurements are therefore of great interest.
The LHCb detector, located at the Large Hadron Collider (LHC) at CERN, is optimised to study rare b-hadron decays. For this purpose LHCb features high trigger efficiencies, excellent track reconstruction and particle identification.
This talk summarises the status of the measurement Rφ, which benefits from the experimentally clean Bs → φ ℓ+ℓ− decay. The analysis is using the full Run 1 and Run 2 dataset collected by LHCb that corresponds to 9 fb−1 of integrated luminosity.