Two-Photon Exchange: Future Experimental Prospects
Abstract The proton elastic form factor ratio is accessible in unpolarized Rosenbluth-type experiments as well as experiments which make use of polarization degrees of freedom. The extracted values show a distinct discrepancy, growing with...
| Main Author: | |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Springer Vienna
2021
|
| Online Access: | https://hdl.handle.net/1721.1/131800 |
| Summary: | Abstract
The proton elastic form factor ratio is accessible in unpolarized Rosenbluth-type experiments as well as experiments which make use of polarization degrees of freedom. The extracted values show a distinct discrepancy, growing with
$$Q^2$$
Q
2
. Three recent experiments tested the proposed explanation, two-photon exchange, by measuring the positron–proton to electron–proton cross section ratio. In the results, a hard two-photon exchange effect at the couple-of-percent level is visible, significantly different from theoretical calculation. Theory at larger momentum transfer remains untested. This paper discusses the possibilities for future measurements at larger momentum transfer. |
|---|