Next-to-leading order perturbative QCD predictions for exclusive <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>J</mml:mi><mml:mo>/</mml:mo><mml:mi>ψ</mml:mi></mml:mrow></mml:math> photoproduction in oxygen-oxygen and lead-lead collisions at energies available at the CERN Large Hadron Collider
K. Eskola, Chris A. Flett, V. Guzey, Topi Löytäinen, Hannu Paukkunen
Abstract
We present predictions for the cross sections of coherent $J/\ensuremath{\psi}$ photoproduction in lead-lead and oxygen-oxygen ultraperipheral collisions (UPCs) as a function of the $J/\ensuremath{\psi}$ rapidity at the LHC in the framework of collinear factorization at next-to-leading order (NLO) in perturbative QCD. Taking generalized parton distribution functions in their forward limit and using the EPPS21, nNNPDF3.0, and nCTEQ15WZSIH nuclear parton distribution functions, we update our recent results for Pb-Pb collisions, make detailed predictions for O-O collisions for several beam energy configurations, and examine the ratio of O-O and Pb-Pb UPC cross sections. We show that the latter observable allows one to significantly reduce the scale uncertainty of NLO predictions for this process.