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

M. Ablikim, M.N. Achasov, P. Adlarson, S. Ahmed, M. Albrecht, R. Aliberti, A. Amoroso, M.R. An, Q. An, X.H. Bai, Y. Bai, O. Bakina (+508 others)
2021 Physics Letters B  
The electromagnetic process e + e − → pp 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 pp 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.
doi:10.1016/j.physletb.2021.136328 fatcat:hbfmcyco7ffzpded2gmrxxlgoi