https://doi.org/10.1140/epja/s10050-021-00633-2
Regular Article - Experimental Physics
A measurement of two-photon exchange in Super-Rosenbluth separations with positron beams
1
Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA
2
Los Alamos National Laboratory, 87545, Los Alamos, NM, USA
Received:
9
March
2021
Accepted:
14
November
2021
Published online:
29
November
2021
The proton electric and magnetic form factors, 
and 
, are intrinsically connected to the spatial distribution of charge and magnetization in the proton. For decades, Rosenbluth separation measurements of the angular dependence of elastic e
-p scattering were used to extract and . More recently, polarized electron scattering measurements, aiming to improve the precision of extractions, showed significant disagreement with Rosenbluth measurements at large momentum transfers (
). This discrepancy is generally attributed to neglected two-photon exchange (TPE) corrections. At larger values, a new ‘Super-Rosenbluth’ technique was used to improve the precision of the Rosenbluth extraction, allowing for a better quantification of the discrepancy, while comparisons of e
-p and e-p scattering indicated the presence of TPE corrections, but at values below where a clear discrepancy is observed. In this work, we demonstrate the significant benefits to combining the Super-Rosenbluth technique with positron beam measurements. This approach provides a greater kinematic reach and is insensitive to some of the key systematic uncertainties in previous positron measurements.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2021
