2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/220327We demonstrate that the collinear expansion fails in the case of gluon emission from a fast quark produced in $eA$ DIS. In this approximation the N=1 rescattering contribution to the gluon spectrum vanishes. We show that the higher-twist approach by Guo, Wang and Zhang [4,5] based on the collinear expansion is wrong. The nonzero gluon spectrum obtained in [4,5] is a consequence of unjustified neglecting some important terms in the collinear expansion.10 pages, 2 eps figuresHigh Energy Physics - Phenomenologytext