Precision measurements of the timelike electromagnetic form factors of the pion, kaon, and proton.

摘要

Using 20.7 pb-1 of e+ e- annihilation data taken at 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 GeV2 by the reaction e +e- → h +h-. The measurements are the first ever with identified pions and kaons of |Q2| > 4 GeV2, with the results |Fpi(13.48 GeV 2)| = 0.075+/-0.008(stat)+/-0.005(syst) and |F K(13.48 GeV2)| = 0.063+/-0.004(stat)+/-0.001(syst). The result for the proton, assuming | GPE (Q2)| = | GPM (Q2)|, is GPM |(13.48 GeV2)| = 0.0139+0.0024-0.0018 (stat) +/- 0.0006(syst), which is in agreement with earlier results.