Determination of the Pion Charge Form Factor at ${Q}^{2}=1.60$ and $2.45\text{ }\text{ }(\mathrm{GeV}/c{)}^{2}$

Determination of the Pion Charge Form Factor at $Q^{2} = 1.60$ and $2.45 (GeV / c)^{2}$

T. Horn et al. (Jefferson Lab F_{π} Collaboration)

Phys. Rev. Lett. 97, 192001 – Published 6 November 2006

Abstract

The ${}^{1}H (e, e^{'} π^{+}) n$ cross section was measured at four-momentum transfers of $Q^{2} = 1.60$ and $2.45 {GeV}^{2}$ at an invariant mass of the photon nucleon system of $W = 2.22 GeV$ . The charged pion form factor ( $F_{π}$ ) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which $F_{π}$ is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of $Q^{2}$ by one sigma, but is still far from its perturbative quantum chromodynamics prediction.