학술논문
Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering
Document Type
article
Author
Christy, ME; Gautam, T; Ou, L; Schmookler, B; Wang, Y; Adikaram, D; Ahmed, Z; Albataineh, H; Ali, SF; Aljawrneh, B; Allada, K; Allison, SL; Alsalmi, S; Androic, D; Aniol, K; Annand, J; Arrington, J; Atac, H; Averett, T; Gayoso, C Ayerbe; Bai, X; Bane, J; Barcus, S; Bartlett, K; Bellini, V; Beminiwattha, R; Bericic, J; Bhatt, H; Bhetuwal, D; Biswas, D; Brash, E; Bulumulla, D; Camacho, CM; Campbell, J; Camsonne, A; Carmignotto, M; Castellanos, J; Chen, C; Chen, J-P; Chetry, T; Cisbani, E; Clary, B; Cohen, E; Compton, N; Cornejo, JC; Dusa, S Covrig; Crowe, B; Danagoulian, S; Danley, T; Deconinck, W; Defurne, M; Desnault, C; Di, D; Dlamini, M; Duer, M; Duran, B; Ent, R; Fanelli, C; Fuchey, E; Gal, C; Gaskell, D; Georges, F; Gilad, S; Glamazdin, O; Gnanvo, K; Gramolin, AV; Gray, VM; Gu, C; Habarakada, A; Hague, T; Hamad, G; Hamilton, D; Hamilton, K; Hansen, O; Hauenstein, F; Hernandez, AV; Henry, W; Higinbotham, DW; Holmstrom, T; Horn, T; Huang, Y; Huber, GM; Hyde, C; Ibrahim, H; Israel, N; Jen, C-M; Jin, K; Jones, M; Kabir, A; Karki, B; Keppel, C; Khachatryan, V; King, PM; Li, S; Li, W; Liu, H; Liu, J; Liyanage, AH; Mack, D; Magee, J
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Abstract
We present new precision measurements of the elastic electron-protonscattering cross section for momentum transfer (Q$^2$) up to 15.75~\gevsq.Combined with existing data, these provide an improved extraction of the protonmagnetic form factor at high Q$^2$ and double the range over which alongitudinal/transverse separation of the cross section can be performed. Thedifference between our results and polarization data agrees with that observedat lower Q$^2$ and attributed to hard two-photon exchange (TPE) effects,extending to 8~(GeV/c)$^2$ the range of Q$^2$ for which a discrepancy isestablished at $>$95\% confidence. We use the discrepancy to quantify the sizeof TPE contributions needed to explain the cross section at high Q$^2$.