Publications
Publication Information
| Title | Determination of two-photon exchange via $e^+p/e^-p$ Scattering with CLAS12 |
| Authors | Jan Bernauer, Volker Burkert, Ethan Cline, Axel Schmidt, Youri Sharabian |
| JLAB number | JLAB-PHY-21-3509 |
| LANL number | arXiv:2103.03948 |
| Other number | DOE/OR/23177-5326 |
| Document Type(s) | (Journal Article) |
| Associated with EIC: | No |
| Supported by Jefferson Lab LDRD Funding: | No |
| Funding Source: | Nuclear Physics (NP) |
| Other Funding: | NSF PHY-2012114. |
|
Journal Compiled for European Physical Journal A Volume 57 Page(s) 144 Refereed | |
| Publication Abstract: | The proton elastic form factor ratio shows a discrepancy between measurements using the Rosenbluth technique in unpolarized beam and target experiments and measurements using polarization degrees of freedom. The proposed explanation of this discrepancy is uncorrected hard two-photon exchange (TPE), a type of radiative correction that is conventionally neglected. The effect size and agreement with theoretical predictions has been tested recently by three experiments. While the results support the existence of a small two-photon exchange effect, they cannot establish that theoretical treatments are valid. At larger momentum transfers, theory remains untested. This proposal aims to measure two-photon exchange over an extended and so far largely untested $Q^2$ and $\varepsilon$ range with high precision using the {\tt CLAS12} experiment. Such data are crucial to clearly confirm or rule out TPE as the driver for the discrepancy as well as test several theoretical approaches, believed valid in different parts of the tested $Q^2$ range. |
| Experiment Numbers: | |
| Group: | Hall B |
| Document: | |
| DOI: | https://doi.org/10.1140/epja/s10050-021-00462-3 |
| Accepted Manuscript: | 2103.03948.pdf |
| Supporting Documents: | |
| Supporting Datasets: | |