The currently operating FASER experiment and the planned Forward Physics
Facility (FPF) will detect a large number of neutrinos produced in
proton-proton collisions at the LHC. In addition to neutrinos from pion and
kaon decays, a significant contribution is expected from the decay of charmed
hadrons, particularly for electron and tau neutrino flavors. In this work, we
investigate two QCD formulations for the production of charm quarks in pp
collisions: the next-to-leading order collinear factorization and the
kT​-factorization approach. We use state of the art fragmentation schemes to
obtain hadron cross-sections and validate them against corresponding LHCb data.
These calculations are then used to predict the forward neutrino flux from
charm hadron decays. We further scrutinize the impact of varying QCD
parameters, such as scales, the selection of parton distribution functions, and
the modeling of fragmentation, on these predictions. We find that the
measurement of forward neutrino flux will serve as a complementary tool to
probe QCD dynamics and will offer valuable insights for astroparticle physics.Comment: 25 pages, 12 figure