We report on measurements of the differential ${\mathrm{\pi }}^{\pm }$p cross section at pion energies ${\mathit{T}}_{\mathrm{\pi }}$=32.7, 45.1, and 68.6 MeV. The measurements, covering the angular range 25°≤${\mathrm{\theta }}_{\mathrm{lab}}$≤123°, have been carried out at the Paul-Scherrer-Institute (PSI) in Villigen, Switzerland, employing the magnet spectrometer LEPS. The absolute normalization of the ${\mathrm{\pi }}^{\pm }$p cross sections have been achieved by relating them to the electromagnetic cross sections of ${\mathrm{\mu }}^{\pm \mathrm{}12}$C scattering. The results are in agreement with those of our preceding measurements at ${\mathit{T}}_{\mathrm{\pi }}$=32.2 and 45.1 MeV insofar as they overlap with the region of the Coulomb nuclear interference investigated there. A comparison with the predictions of the Karlsruhe-Helsinki phase shift analysis KH80, which has formed the basis for the determination of the ‘‘experimental’’ σ term, reveals considerable deviations. These are most pronounced for the ${\mathrm{\pi }}^{+}$p cross sections at ${\mathit{T}}_{\mathrm{\pi }}$=32.7 and 45.1 MeV. Single energy partial wave fits result in S-wave contributions, which are about 1° lower in magnitude then those specified by the KH80 solution. The data at 68.6 MeV are in good agreement with the phase shift analysis.

• Received 8 November 1994

DOI:https://doi.org/10.1103/PhysRevC.51.2159