The project PRECISION has two main work areas: the scan of purely leptonic beauty decays including the search for lepton flavour violation and the test of lepton flavour universality. The team members of the ERC grant PRECISION have made significant contributions to the publication of beauty decays to two muons [Phys. Rev. Lett. 118 (2017) 191801] and have guided LHCb's researchers for a search for B -> e mu [JHEP 03 (2018) 078]. The not so sensitive decays to tau leptons have been published by the LHCb collaboration independently of PRECISION [Phys. Rev. Lett. 118 (2017) 251802]. The researchers of PRECISION have then focussed on a search for Lepton Flavour Violation in B-> Kemu decays, one of the most interesting modes of this kind. The analysis is finished and has been presented by the PRECISION researcher Titus Mombächer on the MIAPP workshop in May 2018 [Phys. Rev. Lett.123 (2019) 241802]. The second focus in this area is the search for purely electronic B decays, the search for B and Bs -> e+e- [Phys. Rev. Lett. 124 (2020) 211802]. This measurement improved the former bounds by more than a factor of 30. Recently, B meson decays to four muons has been searched for [JHEP 03 (2022) 109], no signal was seen. This imposes strong constraints on proposed new light scalar particles. The measurement of B decays to two muons has also been published with the full LHCb dataset [Phys. Rev. Lett. 128, (2022) 041801, Phys. Rev. D105 (2022) 012010], one of the roadmap measurements of LHCb. Concerning lepton flavour universality, the tests have been extended to the baryon sector with Lb -> pK ll decays [JHEP 05 (2020) 040], and recently, the last measurement of the program of PRECISION has been published: an test of lepton flavour uiniversality inclusively measured in several bins of the decays B+ -> K+ ll and B0 -> K*0 ll [arXiv:2212.09152 (submitted to PRL), arXiv:2212.09153 (submitted to PRD)]. Especially this last measurement sparked a lot of interest, as it reduces the tension to teh SM compared to the previously published evidence for New Physics.
The project PRECISION also had another component, the developemnt and implementation of a novel trigger system for the LHCb experiment. The system has been proposed [Computing and Software for Big Science volume 4, Article number: 7 (2020)] and later validated for performance [Computing and Software for Big Science volume 6, Article number: 1 (2022)]. The novel system, with a triggerless readout and a full software trigger implemented in GPU's at the first stage now runs as trigger system of LHCb for Run 3.
