Apparent violation of unitarity in elastic pi /sup -/p scattering

The author deduces that if f(cos theta ) has nonnegative partial waves, then (f(cos theta )/f(1))/sup 2/<or=/sup 1///sub 3/+/sup 2 ///sub 3/f(/sup 1///sub 2/(3 cos/sup 2/ theta -1))/f(1) for -1<or=cos theta <or=1. Applying this, it is shown that recent determinations of the pi /sup -/p slope parameter for mod t mod <or=0.04 (GeV/c)/sup 2/ at 100 GeV/c at CERN, together with those at larger mod t mod at Fermilab, imply a substantial violation of unitarity, though each determination by itself is consistent with unitarity. (8 refs).