LHCb detector proves it can catch hints of physics beyond current theory
Physicists have validated that the upgraded LHCb experiment can measure rare particle decay patterns with the precision needed to detect deviations from established physics. The successful benchmark clears the way for searches that could reveal entirely new particles or forces lurking at nature's smallest scales—discoveries that could reshape fundamental science.
Originaltitel: Differential decay rate of B+ → J/ψK+ with the LHCb Upgrade I experiment
A bstract The normalised decay rate of B + → J/ψ (→ μ + μ − ) K + is measured as a function of the lepton helicity angle using a data sample corresponding to an integrated luminosity of 1 . 1 fb − 1 collected during October 2024 with the upgraded (Upgrade I) LHCb detector. This angular distribution can be parameterised by two coefficients, the forward-backward asymmetry, A FB , and the flatness parameter, F H , whose values are constrained by conservation of angular momentum. These coefficients are measured both integrated and differentially across various kinematic and detector-response variables, and the results are found to be in good agreement with expectations. These measurements show that the detector response of the LHCb Upgrade I experiment is understood to the precision required to reliably extract the angular coefficients associated with rare b → sμ + μ − and b → dμ + μ − transitions, which are particularly sensitive to physics beyond the Standard Model.