Measurement of the polarization parameter of the reactionsπ− p → π0n and ηn at 5 and 8 GeV/c

Measurements of the polarization parameter of the reactions π^?p → π⁰n and π^?p → ηn at 4.90 and 7.85 GeV/c and for a squared four-momentum transfer ?t ranging from 0.1 to 2.0 (GeV/c)² have been achieved by using a butanol polarized proton target and detecting only the two γ's from the neutral meson decay. The background due to events involving bound protons has been separately measured and subtracted out. A large positive polarization has been found for the reaction π^?p → π⁰n. It is consistent with other pion-nucleon scattering data connected by isospin conservation. The polarization for the reaction π^?p → ηn is not significantly different from zero within the large experimental errors.