Two-Photon Exchange Effect in the Elastic Electron-Nucleon Scattering
博士 === 國立臺灣大學 === 物理研究所 === 95 === When measuring the nucleon form factors, recent polarization experiments at the Thomas Jefferson Laboratory (JLab) have confirmed the earlier Rosenbluth measurements from SLAC at small Q2. However, at large Q2, a huge discrepancy appear between them. To solve this...
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| Format: | Others |
| Language: | en_US |
| Published: |
2007
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| Online Access: | http://ndltd.ncl.edu.tw/handle/26172793068704348562 |
| Summary: | 博士 === 國立臺灣大學 === 物理研究所 === 95 === When measuring the nucleon form factors, recent polarization experiments at the Thomas
Jefferson Laboratory (JLab) have confirmed the earlier Rosenbluth measurements from SLAC
at small Q2. However, at large Q2, a huge discrepancy appear between them. To solve this
puzzle, the two-photon exchange contribution to elastic electron-proton scattering at large
momentum transfer by using a quark-parton representation of virtual Compton scattering was
estimated. And then we thus can relate the two-photon exchange amplitude to the generalized
parton distributions which also enter in other wide angle scattering processes. We find that the interference of one- and two-photon exchange contribution is able to substantially resolve the difference between electric form factor measurements from Rosenbluth and polarization transfer experiments. Now we know higher-order QED effects can play an important role in precision measurements of nucleon elastic form factors in electron scattering.
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