  The energy loss of hard jets produced in the Deep-Inelastic scattering (DIS)
off a large nucleus is considered in the collinear limit. In particular, the
single gluon emission cross section due to multiple scattering in the medium is
calculated. Calculations are carried out in the higher-twist scheme, which is
extended to include contributions from multiple transverse scatterings on both
the produced quark and the radiated gluon. The leading length enhanced parts of
these power suppressed contributions are resummed. Various interferences
between such diagrams lead to the Landau-Pomeranchuk-Migdal (LPM) effect. We
resum the corrections from an arbitrary number of scatterings and isolate the
leading contributions which are suppressed by one extra power of the hard scale
$Q^{2}$. All powers of the emitted gluon forward momentum fraction $y$ are
retained. We compare our results with the previous calculation of single
scattering per emission in the higher-twist scheme as well as with multiple
scattering resummations in other schemes. It is found that the leading
($1/Q^2$) contribution to the double differential gluon production cross
section, in this approach, is equivalent to that obtained from the single
scattering calculation once the transverse momentum of the final quark is
integrated out. We comment on the generalization of this formalism to
Monte-Carlo routines.
