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 μe→μe. The differential cross section of this process, measured as a function of the squared momentum transfer t= q2< 0 , provides direct sensitivity to the leading-order hadronic contribution to the muon anomaly aμHLO. By using a muon beam of 150 GeV, with an average rate of ∼ 1.3 × 10 7 muon/s, currently available at the CERN North Area, a statistical uncertainty of ∼ 0.3% can be achieved on aμHLO after two years of data taking. The direct measurement of aμHLO via 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.
Measuring the leading hadronic contribution to the muon g-2 via μe scattering / Abbiendi, G.; Calame, C. M. Carloni; MARINI BETTOLO MARCONI, Umberto; Matteuzzi, C.; Montagna, G.; Nicrosini, O.; Passera, Mariadele; Piccinini, F.; Tenchini, R.; Trentadue, L.; Venanzoni, G.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 77:3(2017), pp. 139-146. [10.1140/epjc/s10052-017-4633-z]
Measuring the leading hadronic contribution to the muon g-2 via μe scattering
MARINI BETTOLO MARCONI, UMBERTO;PASSERA, Mariadele;Trentadue, L.;
2017-01-01
Abstract
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 μe→μe. The differential cross section of this process, measured as a function of the squared momentum transfer t= q2< 0 , provides direct sensitivity to the leading-order hadronic contribution to the muon anomaly aμHLO. By using a muon beam of 150 GeV, with an average rate of ∼ 1.3 × 10 7 muon/s, currently available at the CERN North Area, a statistical uncertainty of ∼ 0.3% can be achieved on aμHLO after two years of data taking. The direct measurement of aμHLO via 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.