Scattering of Negative Mesons by Hydrogen at 130 and 152 Mev

Abstract

The elastic scattering and total cross sections for negative $\pi$ mesons on hydrogen have been measured at 130 and 152 Mev. At both energies, the number of electrons arising from the charge exchange scattering have been determined with a Čerenkov counter. At 152 Mev, recoil protons were counted, and were distinguished from $\pi$ mesons by energy loss in a scintillator. The real part of the forward scattering amplitude has been determined to be 0.243±0.015 and 0.218±0.016, in units of the meson Compton wavelength, at 130 and 152 Mev, respectively. These values agree within limits of statistical error with the predictions from dispersion relations.