Meson exchange effects in elasticepscattering at loop level and the electromagnetic form factors of the proton

2013/12/31 by Hong-Yu Chen, Hongyu Chen, Hai-Qing Zhou · 2 citations
Mathematics · Physics and Astronomy · #Algorithm #Atomic and Molecular Physics #Computer science #Mathematics #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph #nucl-th

paper · pdf · doi:10.1103/physrevc.90.045205

13 pages, 6 figures

openalex publication_date 2014/10/17 · arxiv created 2014/10/21 · arxiv updated 2015/06/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

A new form of two-photon exchange (TPE) effect is studied to explain the discrepancy between unpolarized and polarized experimental data in elastic ep scattering. The mechanism is based on a simple idea that apart from the usual TPE effects from box and crossed-box diagrams, the mesons may also be exchanged in elastic ep scattering by two-photon coupling at loop level. The detailed study shows such contributions to reduced unpolarized cross section (\ensuremathσ_un) and polarized observables (P_t,P_l) at fixed Q² are only dependent on proton's electromagnetic form factors G_E,M and a new unknown universal parameter g. After combining this contribution with the usual TPE contributions from box and crossed-box diagrams, the ratio \ensuremathμ_pG_E/G_M extracted from the recent precise unpolarized and polarized experimental data can be described consistently.

Citations

• Global analysis of proton elastic form factor data with two-photon exchange corrections
• Proton Structure from the Measurement of 2S-2P Transition Frequencies of Muonic Hydrogen
• Precision Rosenbluth Measurement of the Proton Elastic Form Factors
• Two-photon exchange contribution to elastic electron-nucleonscattering at large momentum transfer
• The size of the proton
• Measurement of G_Ep/G_Mp in ep→ ep to Q² = 5.6 GeV²

Cited by

• Two-Photon Exchange in Elastic Electron Scattering on Hadronic Systems
• Two-photon exchange effects in e+e−→π+π− and timelike pion electromagnetic form factor