中国物理学会高能物理分会第十三届全国粒子物理学术会议（2021）

Nucleons are one of the most fundamental building blocks of ordinary matter, yet their internal structure and dynamics are still not fully understood. Electromagnetic form factors allow to investigate fundamental properties of the nucleon. The BESIII collaboration has studied the time-like form factors of the proton using the energy scan and the ISR technique. The |GE/GM| ratio is obtained with a precision comparable to the investigations of the space-like EMFF in electron proton scattering. The effective form factor of the neutron is measured with highest precision using the scan method. For both nucleons, an intriguing periodic behavior of effective form factors lineshape is observed. In this presentation the latest results on nucleon form factors at BESIII are discussed.