In the last decade, the KLOE/KLOE-2 collaboration performed three precise measurements of the process of production of pions couple at DAΦNE, the electron-positron collider operating at the INFN Frascati National Laboratories.
These measurements are particularly important for the study of the anomalous magnetic moment of the muon (g-2) and for its accurate determination (better than one part of a million). To this day, there is still an indication of discrepancy between the theoretical prevision of the Standard Model and the value of the muon g-2 measured. This deviation, if confirmed by the next experiments, among which the “muon g-2” currently performed at Fermilab of Chicago (USA) and to which INFN participates, could indicate the existence of new physics beyond the Standard Model.
The data collected by the KLOE experiment have recently been analyzed once again and it has been published a combined measurement that is the most precise measurement currently available of the contribution of the two pions to the g-2 calculation, a very significant contribution among the “hadronic” ones, which cannot be directly estimated but indirectly derived from the measures of electron-positron annihilation in hadrons. These data have been made available to the physicists community committed in this sector and will play a key role in the study of the muon g-2 in the next years.
For the details of this analysis see here: https://link.springer.com/article/10.1007%2FJHEP03%282018%29173
Translation by Camilla Paola Maglione, Communications Office INFN-LNF