The MUonE experiment: a novel way to measure the hadronic contribution to the muon g-2
by
DrRiccardo Pilato(University of Liverpool)
→
Europe/London
OLL/3-337 - Seminar Room (Liverpool Physics)
OLL/3-337 - Seminar Room
Liverpool Physics
Description
The muon anomalous magnetic moment exhibits a long standing discrepancy between theory and experiment. The comparison with the Standard Model prediction is currently limited by tensions in the evaluation of the leading order hadronic contributions to the muon anomaly, $a_\mu^\text{HLO}$. This quantity is traditionally determined through a data-driven approach involving the measurement of $e^+e^-$ annihilation cross sections into hadrons. A recent calculation of $a_\mu^\text{HLO}$ based on lattice QCD techniques shows a $2.1\sigma$ discrepancy with the dispersive one, while a new $e^+e^-$ cross section measurement disagrees with the previous results. Independent crosschecks are thus required to solve this tension and consolidate the theoretical prediction.
The MUonE experiment proposes a novel approach to determine $a_\mu^\text{HLO}$, based on the extraction of the running of the electromagnetic coupling constant in the space-like region from a very precise measurement of the $\mu - e$ elastic scattering differential cross section. The measurement will be performed at CERN North Area by scattering a 160 GeV muon beam on the atomic electrons of a low-Z target. A pilot run was held in September 2023 with a reduced detector to validate the experimental proposal. The main concepts and challenges of the experiment will be presented in this talk.