Results and Future Prospects of Exclusive Vector Meson Production with pPb Collisions at CMS

Abstract

Exclusive photoproduction of vector mesons (Upsilon and Rho\(^{0}\)) is studied with the large photon flux available in ultra-peripheral pPb collisions at \(\sqrt{s_{\mathrm{NN}}} \)=5.02 TeV with the CMS experiment. It provides a clean probe of the gluon distribution at small values of parton fractional momenta x at central rapidities (\(|y| < 2.5\)). The cross sections are measured as a function of the photon-proton centre-of-mass energy, extending the energy range explored by H1 and ZEUS experiments at HERA. In addition, the differential cross sections (\(d\sigma /dt\)), where |t| \(\approx p_\mathrm{T}^2\), the squared transverse momentum of produced vector mesons, are measured and the slope parameters are obtained. The results are compared to previous measurements and to theoretical predictions. Finally, prospects for further measurements of vector meson production that can be performed using pPb collision data at 8 TeV collected at the end of 2016 are presented.