Measuring the leading hadronic contribution to the muon g-2 via the -e elastic scattering.

¹ INFN Sezione di Bologna, Via Irnerio, 46 - 40126 Bologna (BO) Italy.
² INFN Sezione di Pavia, Via Agostino Bassi, 6 - 27100 Pavia (PV) Italy.

^a Corresponding authorumberto.marconi@bo.infn.it ^b Corresponding authorfulvio.piccinini@pv.infn.it

Published online: 23 May 2018

Abstract

The precision measurement of the anomalous magnetic moment g-2 of the muon presently exhibits a 3.5 σ deviation between theory and experiments. In the next few years the anomalous magnetic moment will be measured to higher precisions at Fermilab and J-PARC. The theoretical prediction can be improved by reducing the uncertainty on the leading hadronic correction ^HLO μ to the g-2. Here we present a novel approach to determine a^HLO μ with space-like data, by means of precise measurement of the hadronic shift of the effective electromagnetic coupling α exploiting the elastic scattering of 150 GeV muons (currently available at CERN North area) on atomic electrons of a low-Z target. The direct measurement of a^HLO μ in the space-like region will provide a new independent determination competitive with the time-like dispersive approach, and will consolidate the theoretical prediction of the muon g-2 in the Standard Model. It will allow therefore a firmer interpretation of the measurements of the future muon g-2 experiments at Fermilab and J-PARC