Measuring the leading hadronic contribution to the muon g-2 via $$\mu e$$μe scattering

By G. Abbiendi, C. Calame, U. Marconi, C. Matteuzzi, G. Montagna, O. Nicrosini, M. Passera, F. Piccinini, R. Tenchini, L. Trentadue and 1 more. 2016

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We propose a new experiment to measure the running of the electromagnetic coupling constant in the space-like region by scattering high-energy muons on atomic electrons of a low-Z target through the elastic process $$\mu \, e \rightarrow \mu \, e$$μe→μe. The differential cross section of this process, measured as a function of the squared momentum transfer $$t=q^2<0$$t=q2<0, provides direct sensitivity to the leading-order hadronic contribution to the muon anomaly $$a^\mathrm{{HLO}}_{\mu }$$aμHLO. By using a muon beam of 150 GeV, with an average rate of $$\sim $$∼1.3 $$\times 10^7$$×107 muon/s, currently available at the CERN North Area, a statistical uncertainty of $$\sim $$∼0.3% can be achieved on $$a^\mathrm{{HLO}}_{\mu }$$aμHLO after two years of data taking. The direct measurement of $$a^\mathrm{{HLO}}_{\mu }$$aμHLO via $$\mu e$$μe scattering will provide an independent determination, competitive with the time-like dispersive approach, and consolidate the theoretical prediction for 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.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/926d43973251fc7f10d6534398ac48bad7d66342