https://doi.org/10.1140/epjc/s10052-016-4493-y
Regular Article - Theoretical Physics
The exclusive J/
process at the LHC tamed to probe the low x gluon
1
Max-Planck-Institute for Physics, Föhringer Ring 6, 80805, Munich, Germany
2
Institute for Particle Physics Phenomenology Durham University, Durham, DH1 3LE, UK
3
Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, St. Petersburg, 188300, Russia
4
Department of Mathematical Sciences, University of Liverpool, Liverpool, L69 3BX, UK
* e-mail: a.d.martin@durham.ac.uk
Received:
10
October
2016
Accepted:
6
November
2016
Published online:
21
November
2016
The perturbative QCD expansion for 
photoproduction appears to be unstable: the NLO correction is large (and of opposite sign) to the LO contribution. Moreover, the predictions are very sensitive to the choice of factorisation and renormalisation scales. Here we show that perturbative stability is greatly improved by imposing a 
cut’ on the NLO coefficient functions; a cut which is required to avoid double counting. 
is the input scale used in the parton DGLAP evolution. This result opens the possibility of high precision exclusive data in the forward direction at the LHC being able to determine the low x gluon distribution at low scales.
© The Author(s), 2016
