  We address the question as to whether data for J/\psi mesons produced
exclusively in the forward direction at the LHC can be used in global parton
analyses (based on collinear factorization) to pin down the low x gluon PDF. We
show that it may be possible to overcome the problems that (i) the process is
described by a skewed or Generalized Parton Distribution (GPD), (ii) it is very
sensitive to the choice of factorization scale and (iii) there is bad LO,
NLO,... perturbative stability to the predictions. However, we start by briefly
explaining how the alternative k_T factorization approach has been used to
describe the process.
