Electroproduction of single pions at low ε and a measurement of the pion form factor up to Q2=10 GeV2

Abstract

We report measurements of the electroproduction of single charged pions from hydrogen and deuterium targets for values of $\epsilon$ in the range $0.35<\mathrm{}\epsilon <0.45\mathrm{}$. Data were taken with a hydrogen target at the ($W, Q^2$) points (2.15 GeV, 1.2 ${\mathrm{GeV}}^2$), (2.65, 2.0), (2.65, 3.4), (2.65, 6.0), and (2.65, 10.0). Data were taken with a deuterium target at the ($W, Q^2$) points (2.15, 1.2) and (2.65, 2.0). The transverse cross section obtained by using these data in conjunction with earlier data at high $\epsilon$ to separate the longitudinal and transverse components is used in conjunction with the new data and the $t$-channel Born term to determine the pion form factor and to re-evaluate previously reported measurements. In the range $0.15 \mathrm{Ge}{\mathrm{V}}^2<Q^2<10.0\mathrm{} \mathrm{Ge}{\mathrm{V}}^2$ the pion form factor can be described by the simple pole form ${[1+\frac{Q^2}{(0.462\mathrm{}\pm 0.024)}]}^{-1\mathrm{}}$.