Precision Measurements of the Timelike Electromagnetic Form Factors of Pion, Kaon, and Proton

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Using 20.7 pb-1 of e+e- annihilation data taken at sqrts = 3.671 GeV with the CLEO-c detector, precision measurements of the electromagnetic form factors of the charged pion, charged kaon, and proton have been made for timelike momentum transfer of |Q²| = 13.48 GeV² by the reaction e+e- to h+h-. The measurements are the first ever with identified pions and kaons of |Q²| > 4 GeV², with the results Fₚi(13.48 GeV²) = 0.075+-0.008(stat)+-0.005(syst) and Fₖ(13.48 GeV²) = 0.063+-0.004(stat)+-0.001(syst). The result for the proton, assuming Gᵖₑ = Gᵖₘ, is Gᵖₘ(13.48 GeV²) = 0.014+-0.002(stat)+-0.001(syst), which is in agreement with earlier results.