Measurement of the proton form factor by studying $e^{+}{e}^{-}\to p\bar{p}$

Using data samples collected with the BESIII detector at the BEPCII collider, we measure the Born cross section of $e^{+}{e}^{-}\to p\bar{p}$ at 12 center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective electromagnetic form factor of the proton is deduced under the assumption that the electric and magnetic form factors are equal $(\mathrm{\mid }{G}_E\mathrm{\mid }=\mathrm{\mid }{G}_M\mathrm{\mid })$. In addition, the ratio of electric to magnetic form factors, $\mathrm{\mid }{G}_E\mathrm{/}{G}_M\mathrm{\mid }$, and $\mathrm{\mid }{G}_M\mathrm{\mid }$ are extracted by fitting the polar angle distribution of the proton for the data samples with larger statistics, namely at $\sqrt{s}=$ 2232.4 and 2400.0 MeV and a combined sample at $\sqrt{s}$ = 3050.0, 3060.0 and 3080.0 MeV, respectively. The measured cross sections are in agreement with recent results from BaBar, improving the overall uncertainty by about 30%. The $\mathrm{\mid }{G}_E\mathrm{/}{G}_M\mathrm{\mid }$ ratios are close to unity and consistent with BaBar results in the same $q^2$ region, which indicates the data are consistent with the assumption that $\mathrm{\mid }{G}_E\mathrm{\mid }=\mathrm{\mid }{G}_M\mathrm{\mid }$ within uncertainties.