Power-suppressed contributions to deep-inelastic processes

We present results of a direct calculation of leading power-law corrections to the proton and pion structure functions at large x to order 1/Q4 for νW2/sup proton/ and 1/Q2 for W/sub L//sup proton/ and to order 1/Q2 for νW2/sup pion/ and W/sub L//sup pion/. For νW2 we find large approx.(1-x)4 corrections to the leading approx.(1-x)3 behavior as x→1 and substantial (1-x)2/Q2 corrections, a phenomenologically desirable form. We find a very large value for the coefficient of 1/Q2 in (sigma/sub L//sigma/sub T/)/sup proton/. The 1/Q2 correction to νW2/sup pion/ is of the form proposed by Berger and Brodsky but much smaller than their estimate after complete normalization constraints are imposed. In addition, this correction is not purely longitudinal until (1-x) is very near zero