Large-angle proton and pion production in deep-inelastic electron scattering

Abstract

We have measured $\mathrm{ep}$, $e{\pi }^{+}$, and $e{\pi }^{-}$ coincidences for scattered electrons in the range $Q^2=0.4\mathrm{} \mathrm{to} 2.2$ Ge${\mathrm{V}}^2$ and $W=2\mathrm{} \mathrm{to} 4$ GeV. We find (a) that vector-meson production decreases with $Q^2$ more rapidly than does the total virtual-photon-plus-proton cross section, more rapidly even than the prediction of simple vector dominance, (b) that the slope of the $t$ distribution in $\rho$ and $\omega$ production becomes flatter with increasing $Q^2$ and seems to be at least approximately a function of the single variable $x_{\rho }=\frac{(Q^2+m_{\rho }^2)}{2M\nu }$, (c) that the fraction of final states containing a proton decreases with increasing $Q^2$, (d) that in the central region of longitudinal momenta the inclusive ${\pi }^{+}$ yield seems to increase relative to the ${\pi }^{-}$ yield as $Q^2$ increases, and (e) that the average transverse momentum of ${\pi }^{-}$ is greater than of ${\pi }^{+}$ in the central region of longitudinal momenta.