Jul 6 – 13, 2022
Bologna, Italy
Europe/Rome timezone

Measurement of the anomalous spin precession frequency in the Muon g-2 experiment at Fermilab

Jul 8, 2022, 11:15 AM
Room 9 (Indaco)

Room 9 (Indaco)

Parallel Talk Quark and Lepton Flavour Physics Quark and Lepton Flavour Physics


Lorenzo Cotrozzi (Istituto Nazionale di Fisica Nucleare)


The muon anomaly, $a_\mu=(g_{\mu}-2)/2$, is a low-energy observable which can be both measured and computed to high precision, making it a sensitive test of the Standard Model and a probe for new physics. The current discrepancy between the Standard Model calculation from the Muon $g-2$ Theory Initiative [T. Aoyama et al. - Phys. Rept. 887 (2020), 1-166] and the experimental value is $a_{\mu}^{SM}-a_{\mu}^{exp}=(251\pm59)\cdot10^{-11}$, with a significance of $4.2\,\sigma$.
The anomaly was measured with a precision of $0.54\,$ppm by the Brookhaven E821 experiment and the E989 experiment at Fermilab aims for a four-fold improvement in precision, to confirm or refute the discrepancy. In Spring 2021, E989 published the first results of $a_{\mu}$ with a precision of $0.46\,$ppm from the 2018 data-taking campaign. The measurement of the anomalous muon spin precession frequency, $\omega_a$, is based on the arrival time distribution of high-energy decay positrons observed by $24$ electromagnetic calorimeters, placed around the inner circumference of the $g-2$ storage ring. This talk will present the status of $\omega_a$ analysis performed on the datasets collected during Run 2 and 3 (2019 and 2020 campaigns), with a preliminary analysis of the systematic uncertainties.

In-person participation Yes

Primary authors

Lorenzo Cotrozzi (Istituto Nazionale di Fisica Nucleare) Mr Matteo Sorbara (Università degli Studi di Roma Tor Vergata & INFN Sezione Roma Tor Vergata)

Presentation materials