arxiv ref: 1608.03838Title: Exclusive $J/\psi$ and Upsilon photoproduction and the low $x$ gluonAuthors: S. P. Jones, A. D. Martin, M. G. Ryskin, T. TeubnerNode: ALU-FRUDURESRs: ESR8Work Packages: WP3: ToolsMilestones: M3.3.3 Improved PDFs using LHC data