Absolute differential cross sections for pi +/-p elastic scattering at 30

Abstract

Absolute ${\mathrm{\ensuremath{\pi}}}^{\ifmmode\pm\else\textpm\fi{}}$p differential cross sections have been measured at incident pion energies of 30.0, 45.0, and 66.8 MeV, using active targets of scintillator plastic (${\mathrm{CH}}_{1.1}$) to detect recoil protons in coincidence with scattered pions. Statistical uncertainties are typically \ifmmode\pm\else\textpm\fi{}3%; systematic uncertainties are \ifmmode\pm\else\textpm\fi{}2%. The results are consistent with two earlier measurements by this group employing different experimental techniques at 67 MeV and higher incident pion energies. The ${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$p cross sections are in good agreement with currently accepted phase-shift analyses, but the corresponding ${\mathrm{\ensuremath{\pi}}}^{+}$p predictions are typically 15% higher at large angles than the ${\mathrm{\ensuremath{\pi}}}^{+}$p cross sections reported here.