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arXiv · 1809.11080

Measurement of exclusive $Υ$ photoproduction from protons in pPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV

CMS Collaboration
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Abstract

The exclusive photoproduction of $Υ$(nS) meson states from protons, $γ$p $ \toΥ$(nS)p (with n = 1, 2, 3), is studied in ultraperipheral pPb collisions at a centre-of-mass energy per nucleon pair of $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV. The measurement is performed using the $Υ$(nS) $\to μ^+μ^-$ decay mode, with data collected by the CMS experiment corresponding to an integrated luminosity of 32.6 nb$^{-1}$. Differential cross sections as functions of the $Υ$(nS) transverse momentum squared $p_\mathrm{T}^2$, and rapidity $y$, are presented. The $Υ$(1S) photoproduction cross section is extracted in the rapidity range $|y|$ $<$ 2.2, which corresponds to photon-proton centre-of-mass energies in the range 91 $<$ W$_{γ\mathrm{p}}$ $<$ 826 GeV. The data are compared to theoretical predictions based on perturbative quantum chromodynamics and to previous measurements.

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CMS Collaboration. 2019-04-03. Measurement of exclusive $Υ$ photoproduction from protons in pPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV. https://doi.org/10.1140/epjc%2Fs10052-019-6774-8

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