  The complete understanding of the basic constituents of hadrons and the
hadronic dynamics at high energies are two of the main challenges for the
theory of strong interactions. In particular, the existence of intrinsic heavy
quark components in the hadron wave function must be confirmed (or disproved).
In this paper we propose a new mechanism for the production of $D$-mesons at
forward rapidities based on the Color Glass Condensate (CGC) formalism and
demonstrate that the resulting transverse momentum spectra are strongly
dependent on the behavior of the charm distribution at large Bjorken $x$. Our
results show clearly that the hypothesis of intrinsic charm can be tested in
$pp$ and $p(d) A$ collisions at RHIC and LHC.
