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 1Q⁴ for νW₂ᵖʳᵒᵗᵒⁿ and 1Q² for WLᵖʳᵒᵗᵒⁿ and to order 1Q² for νW₂ᵖⁱᵒⁿ and WLᵖⁱᵒⁿ. For νW₂ we find large ~(1-x)⁴ corrections to the leading ~(1-x)³ behavior as x→1 and substantial (1-x)²Q² corrections, a phenomenologically desirable form. We find a very large value for the coefficient of 1Q² in (σLσT)ᵖʳᵒᵗᵒⁿ. The 1Q² correction to νW₂ᵖⁱᵒⁿ 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.