  We reconsider the perturbative next-to-leading calculation of the single
inclusive hadron production in the framework of the hybrid formalism, applied
to hadron production in proton-nucleus collisions. Our analysis, performed in
the wave function approach, differs from the previous works in three points.
First, we are careful to specify unambiguously the rapidity interval that has
to be included in the evolution of the leading-order eikonal scattering
amplitude. This is important, since varying this interval by a number of order
unity changes the next-to-leading order correction that the calculation is
meant to determine. Second, we introduce the explicit requirement that fast
fluctuations in the projectile wave function which only exist for a short time
are not resolved by the target. This Ioffe time cutoff also strongly affects
the next-to-leading order terms. Third, our result does not employ the
approximation of a large number of colors. Our final expressions are
unambiguous and do not coincide at next-to-leading order with the results
available in the literature.
