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Volume 316 - XXVI International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2018) - WG2: Small-x and Diffraction
Energy dependence of exclusive J/Psi photoproduction in p-Pb interactions at ALICE
J.G. Contreras Nuno* On behalf of the ALICE collaboration
*corresponding author
Full text: pdf
Pre-published on: 2018 September 20
Published on: 2018 November 23
Abstract
The electromagnetic field of a fast moving lead ion at the LHC is an intense source of quasi-real photons. This makes it possible to study $\mathrm{J/}\psi$ exclusive photoproduction off protons in p--Pb collisions, which is sensitive to the gluon content of the target. Measuring the rapidity of the produced vector meson one can compute the centre-of-mass energy $W_{\gamma\mathrm{p}}$ of the photon--proton scattering.

Using LHC Run 1 data, ALICE has measured the cross section for exclusive $\mathrm{J/}\psi$ photoproduction in a wide range of scattering angles. In this contribution, we present, for the first time, preliminary measurements of the cross section using the central-barrel detectors of ALICE, as well as cross sections for a novel topology where one of the muons from the decay of the $\mathrm{J/}\psi$ is detected with the forward-muon spectrometer and the other muon with the central-barrel detectors. These measurements allow us to study the evolution of the cross section with $W_{\gamma\mathrm{p}}$ in the range from 20 GeV to 700 GeV. The measurements are compared to the newest theoretical models.
DOI: https://doi.org/10.22323/1.316.0049
Open Access
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