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

Using $20.7{\mathrm{pb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data taken at $\sqrt{s}=3.671\mathrm{GeV}$ with the $\mathrm{CLEO}\mathrm{\text{−}}c$ detector, precision measurements of the electromagnetic form factors of the charged pion, charged kaon, and proton have been made for timelike momentum transfer of $|Q^2|=13.48{\mathrm{GeV}}^2$ by the reaction $e^{+}{e}^{-}\to h^{+}{h}^{-}$. The measurements are the first ever with identified pions and kaons of $|Q^2|>4{\mathrm{GeV}}^2$, with the results $F_{\pi }(13.48{\mathrm{GeV}}^2)=0.075\pm 0.008(\mathrm{stat})\pm 0.005(\mathrm{syst})$ and $F_K(13.48{\mathrm{GeV}}^2)=0.063\pm 0.004(\mathrm{stat})\pm 0.001(\mathrm{syst})$. The result for the proton, assuming $G_E^p=G_M^p$, is $G_M^p(13.48{\mathrm{GeV}}^2)=0.014\pm 0.002(\mathrm{stat})\pm 0.001(\mathrm{syst})$, which is in agreement with earlier results.