The Muon g-2 experiment has recently announced a new measurement of the giromagnetic anomaly of the muon, obtained with unprecedented precision, which presents fresh evidence of the existence of novel physical phenomena not included in the Standard Model, the reference theory on the subatomic world. The latest experimental results by Muon g-2 show a discrepancy with respect to Standard Model based calculations at the level of 3.3 standard deviations (sigma). This measurement is compatible with a previous experiment, and the combination brings the statistical significance of the discrepancy to 4.2 sigma, just short of the customary 5 sigma required to claim a discovery. 

The Italian group from INFN has contributed to Muon g-2 since the beginning by, among other things, designing and building a sophisticated laser calibration system for the calorimeters, which represents a state of the art device surpassing systems previously in use. This device has been a key ingredient of the fantastic precision achieved by Muon g-2.

After a brief introduction to the experiment and to the importance of the result, we will discuss in greater detail the contribution by the Italian group, with a special emphasis on the role of researchers from INFN Trieste.