High-Energy Elastic Scattering ofπ±,K−, andp¯on Hydrogen at c.m. Angles from 22° to 180°

Abstract

Elastic ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{-}p$, ${K}^{\ensuremath{-}}\ensuremath{-}p$, and $\overline{p}\ensuremath{-}p$ scattering cross sections have been measured using three different experimental arrangements covering the c.m. angular regions \ensuremath{\sim}20\ifmmode^\circ\else\textdegree\fi{}-120\ifmmode^\circ\else\textdegree\fi{}, \ensuremath{\sim}135\ifmmode^\circ\else\textdegree\fi{}-169\ifmmode^\circ\else\textdegree\fi{}, and \ensuremath{\sim}165\ifmmode^\circ\else\textdegree\fi{}-180\ifmmode^\circ\else\textdegree\fi{} at incident momenta from 6 to 17 GeV/c. In the region 130\ifmmode^\circ\else\textdegree\fi{}-180\ifmmode^\circ\else\textdegree\fi{}, only ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{-}p$ scattering was measured. In the angular region near 180\ifmmode^\circ\else\textdegree\fi{}, the energy dependences and shapes of the $\ensuremath{\pi}\ensuremath{-}p$ backward peaks were determined up to crossed-momentum transfers of $u\ensuremath{\sim}\ensuremath{-}2$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. At all energies, the ${\ensuremath{\pi}}^{+}\ensuremath{-}p$ backward peak had a sharp dip at $u=\ensuremath{-}0.13$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$, with no similar effect in the ${\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{-}p$ case. Nearly complete angular distributions of ${\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{-}p$ elastic scattering from 20\ifmmode^\circ\else\textdegree\fi{} to 180\ifmmode^\circ\else\textdegree\fi{} have been obtained at 6 and 10 GeV/c. These results at 6 and 10 GeV/c as well as at 8 GeV/c reveal a sharp dip in ${\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{-}p$ scattering at $t=\ensuremath{-}3$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. Several structures in the form of dips or shoulders were seen in the $\overline{p}\ensuremath{-}p$ angular distributions also, with less pronounced structure observed in ${K}^{\ensuremath{-}}\ensuremath{-}p$ scattering. At fixed momentum transfer, all cross sections when expressed as $\frac{d\ensuremath{\sigma}}{\mathrm{dt}}$ appear to be decreasing with increasing energy.