出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Precise experimental measurements of the nucleon form factors are a test-bed for understanding the nucleon's properties and dynamical behavior emerge from QCD. With high statistics, the cross section of $e^+e^-\to p\bar{p}$ and $e^+e^-\to n\bar{n}$ are both measured with the highest precision in a wide $q^2$ range. An oscillation behavior is observed both on the proton and neutron effective form factor, but with an orthogonal phase difference. The electro and magnetic form factors of proton and the ratio between them are measured simultaneously with much improved precision compared with previous results through the direct annihilation method using the energy scan data from $\sqrt{s}=2.0$ to 3.08 GeV or through ISR method using data at $\sqrt{s}=3.773$ to 4.6 GeV. With the ISR technique, the form factor measurement can reach as low as the mass threshold of $p\bar{p}$ or $n\bar{n}$.
