Measurements of ?+ and ?- time-like electromagnetic form factors for center-of-mass energies from 2.3864 to 3.0200 GeV

The Born cross sections of the e(+)e(-) -> Sigma(+)(Sigma) over bar (-) and e(+)e(-)-> Sigma(-)(Sigma) over bar (+) processes are determined for centerof-mass energy from 2.3864 to 3.0200 GeV with the BESIII detector. The cross section lineshapes can be described properly by a pQCD function and the resulting ratio of effective form factors for the Sigma(+) and Sigma(-) is consistent with 3. In addition, ratios of the Sigma(+) electric and magnetic form factors, vertical bar G(E)/G(M)vertical bar. are obtained at three center-of-mass energies through an analysis of the angular distributions. These measurements, which are studied for the first time in the off-resonance region, provide precision experimental input for understanding baryonic structure. The observed new features of the Sigma(+/-) form factors require more theoretical discussions for the hyperons. (C) 2021 The Author(s). Published by Elsevier B.V.