Analytic pion form factor

Abstract

The pion electromagnetic form factor and two-pion production in electron-positron collisions are simultaneously fitted by a vector dominance model evolving to perturbative QCD at large momentum transfer. This model was previously successful in simultaneously fitting the nucleon electromagnetic form factors (spacelike region) and the electromagnetic production of nucleon-antinucleon pairs (timelike region). For this pion case dispersion relations are used to produce the analytic connection of the spacelike and timelike regions. The fit to all the data is good, especially for the newer sets of time-like data. The description of high-$q^2$ data, in the time-like region, requires one more meson with $\rho$ quantum numbers than listed in the 2014 Particle Data Group review.

10 pages, 7 figures

References in corpus (9)

• Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45 (GeV/c)2
• Measurement of the ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to {\pi }^{+}{\pi }^{-}$ Cross Section between 600 and 900 MeV Using Initial State Radiation
• Precise Measurement of the e+ e- --> pi+ pi- (gamma) Cross Section with the Initial-State Radiation Method at BABAR
• Update of the e^+e^-\toπ^+π^- cross section measured by SND detector in the energy region 400<\sqrt{s}<1000 MeV
• Measurement of sigma(e+ e- -> pi+ pi-) from threshold to 0.85 GeV^2 using Initial State Radiation with the KLOE detector
• Precision measurement of $\sigma (e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\gamma )/\sigma (e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}\gamma )$ and determination of the ${\pi }^{+}{\pi }^{-}$ contribution to the muon anomaly with the KLOE detector
• Spacelike pion form factor from analytic continuation and the onset of perturbative QCD
• Rigorous pion electromagnetic form factor behavior in the space-like region
• Pion form factor in the range -10 GeV^2 < s < 1 GeV^2