  Heavy quark parton distribution functions (PDFs) play an important role in
several Standard Model and New Physics processes. Most analyses rely on the
assumption that the charm and bottom PDFs are generated perturbatively by gluon
splitting and do not involve any non-perturbative degrees of freedom. On the
other hand, non- perturbative, intrinsic heavy quark parton distributions have
been predicted in the literature. We demonstrate that to a very good
approximation the scale-evolution of the intrinsic heavy quark content of the
nucleon is governed by non-singlet evolution equations. This allows to analyze
the intrinsic heavy quark distributions without having to resort to a
full-fledged global analysis of parton distribution functions. We exploit this
freedom to model intrinsic bottom distributions which are so far missing in the
literature. We estimate the impact of the non-perturbative contribution to the
charm and bottom-quark PDFs and on several important parton-parton luminosities
at the LHC.
