Measurement of proton electromagnetic form factors in the time-like region using initial state radiation at BESIII

• Published in: arXiv.org
• Main Authors: Ablikim, M, An, M R, Bai, Y, R Baldini Ferroli, Balossino, I, Bertani, M, Bettoni, D, Bloms, J, Cetin, S A, Chang, W L, Chen, G, Chen, M L, Chen, X R, Cheng, W S, Farinelli, R, Gao, Y, Gersabeck, E M, Goetzen, K, Gong, L, Gradl, W, Guan, C Y, Guo, L B, Han, T T, Hao, X Q, Heinsius, F H, Heinz, C H, Hou, Y R, Huang, L Q, Hussain, T, Ji, Q P, Ji, X B, Ji, Y Y, Jiao, J B, Jiao, Z, Jin, Y, Jing, M Q, Johansson, T, Ke, B C, Kliemt, R, Kuemmel, M, Kupsc, A, Li, D M, Li, S Y, Li, X H, Liang, Y F, Lin, D X, Liu, D, Liu, Fang, Liu, Huanhuan, Liu, K, Liu, Q, Liu, S B, Liu, W M, Lu, X L, Luo, C L, Luo, T, Ma, X Y, Mo, X H, Mo, Y J, Muramatsu, H, Ouyang, Q, Pathak, A, Patteri, P, Qi, K H, Qian, W B, M Rolo, Sarantsev, A, Schnier, C, Schoenning, K, Sosio, S, Spataro, S, Sun, Z T, Tang, C J, Wang, X F, Wang, X L, Wen, S P, White, D J, X Wu, Z Wu, Xiao, S Y, Xu, Q J, Yan, W B, Yang, Zhi, M Ye, Yin, J H, Yuan, Y, Yuncu, A, Zeng, Y, Zhang, Guangyi, Zhang, J Q, Zhang, S, Zhang, Y T, Zhao, Z G, Zheng, Y H, Zhong, B, Zhu, K, Zhu, K J, Zhu, T J, Zhu, Z A, Zou, B S
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 20.02.2021
• Subjects: Angular distribution; Form factors; Helicity; Physics - High Energy Physics - Experiment; Protons
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2102.10337

The electromagnetic process \(e^{+}e^{-}\to p\bar{p}\) is studied with the initial-state-radiation technique using 7.5 fb\(^{-1}\) of data collected by the BESIII experiment at seven energy points from 3.773 to 4.600 GeV. The Born cross section and the effective form factor of the proton are measured from the production threshold to 3.0 GeV/\(c^{2}\) using the \(p\bar{p}\) invariant-mass spectrum. The ratio of electric and magnetic form factors of the proton is determined from the analysis of the proton-helicity angular distribution.