Ablikim, M.Achasov, M. N.Adlarson, P.Ai, X. C.Aliberti, R.Amoroso, A.Çetin, Serkant Ali2024-05-192024-05-1920240031-90071079-7114https://doi.org10.1103/PhysRevLett.132.081904https://hdl.handle.net/20.500.12713/5878Based on data samples collected with the BESIII detector at the BEPCII collider, the process e+e- -> E+ E over bar - is studied at center -of -mass energies ffis ffi p = 2.3960, 2.6454, and 2.9000 GeV. Using a fully differential angular description of the final state particles, both the relative magnitude and phase information of the E+ electromagnetic form factors in the timelike region are extracted. The relative phase between the electric and magnetic form factors is determined to be sin AO = -0.67 +/- 0.29(stat) +/- 0.18(syst) at ffis ffi p = 2.3960 GeV, AO = 55 degrees +/- 19 degrees(stat) +/- 14 degrees(syst) at pffisffi = 2.6454 GeV, and 78 degrees +/- 22 degrees(stat) +/- 9 degrees(syst) at ffis ffi p = 2.9000 GeV. For the first time, the phase of the hyperon electromagnetic form factors is explored in a wide range of four -momentum transfer. The evolution of the phase along with fourmomentum transfer is an important input for understanding its asymptotic behavior and the dynamics of baryons.eninfo:eu-repo/semantics/openAccess[No Keywords]Article132838457707WOS:0011908949000012-s2.0-85186195209N/A10.1103/PhysRevLett.132.081904Q1