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Durham University

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Publication details for Alan Martin

Jones, S. P., Martin, A. D., Ryskin, M. G. & Teubner, T. (2016). The exclusive J/ψ process at the LHC tamed to probe the low x gluon. The European Physical Journal C 76(11): 633.

Author(s) from Durham


The perturbative QCD expansion for J/ψ 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 ‘Q0 cut’ on the
NLO coefficient functions; a cut which is required to avoid
double counting. Q0 is the input scale used in the parton
DGLAP evolution. This result opens the possibility of high
precision exclusive J/ψ data in the forward direction at the
LHC being able to determine the low x gluon distribution at
low scales.