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

TL;DR

This study reports precise measurements of the electromagnetic form factors of pion, kaon, and proton at high timelike momentum transfer, providing new data for understanding hadron structure in particle physics.

Contribution

First measurements of pion and kaon form factors at |Q^2| > 4 GeV^2 using identified particles, expanding knowledge of hadron electromagnetic properties.

Findings

Measured F_pi(13.48 GeV^2) = 0.075+-0.008(stat)+-0.005(syst)

Measured F_K(13.48 GeV^2) = 0.063+-0.004(stat)+-0.001(syst)

Proton magnetic form factor G^p_M(13.48 GeV^2) = 0.014+-0.002(stat)+-0.001(syst)

Abstract

Using 20.7 pb^-1 of e+e- annihilation data taken at sqrt{s} = 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 |Q^2| = 13.48 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 GeV^2, with the results F_pi(13.48 GeV^2) = 0.075+-0.008(stat)+-0.005(syst) and F_K(13.48 GeV^2) = 0.063+-0.004(stat)+-0.001(syst). The result for the proton, assuming G^p_E = G^p_M, is G^p_M(13.48 GeV^2) = 0.014+-0.002(stat)+-0.001(syst), which is in agreement with earlier results.