π±−pTotal Cross Sections in the Range 450 to 1650 Mev

The total cross sections for positive and negative pions on hydrogen were measured at frequent intervals in the energy range from 450 to 1650 Mev. Six scintillation counters measured the transmission of pions at various solid angles, and the results were extrapolated to zero solid angle. The two peaks previously discovered in the ${\pi }^{-}-p$ cross section were observed to be centered at 600±15 Mev and 900±15 Mev. A broad maximum was observed in the ${\pi }^{+}-p$ cross section at approximately 1350 Mev. A "shoulder" at approximately 800 Mev, in a region where the ${\pi }^{+}-p$ cross section is rapidly rising, supports speculation that there is a resonant state at this energy. Except for a small, unresolved difference in absolute values in the ${\pi }^{+}-p$ case, these data agree with those obtained by Brisson et al. at Saclay.