Measurement of Born cross sections for $e^{+}{e}^{-}\to p\bar{p}$ at $\sqrt{s}=3.510-4.946$ GeV

Abstract

We report a measurement of the Born cross section and the effective form factor for the $e^{+}{e}^{-}\to p\bar{p}$ reaction at 47 center-of-mass energies between 3.510 and 4.946 GeV. The measurement is performed using the energy-scan technique and is based on data corresponding to an integrated luminosity of 26 fb\(^{-1}\) collected with the BESIII detector at the BEPCII collider. For the first time, the moduli of the electromagnetic form factor ratio $|G_E/G_M|$ and of the magnetic form factor $|G_M|$ are determined with high precision by analyzing the distribution of the polar angle of the proton at a large timelike momentum transfer. These results provide essential insights into the nature of charmonium(-like) states above the open-charm threshold and the dynamics underlying the proton electromagnetic form factors.

15 pages, 4 figures, etc