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arXiv · 1612.02950

Measurement of the prompt $J/ψ$ pair production cross-section in $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector

ATLAS Collaboration
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Abstract

The production of two prompt $J/ψ$ mesons, each with transverse momenta $p_{\mathrm{T}}>8.5$ GeV and rapidity $|y| < 2.1$, is studied using a sample of proton-proton collisions at $\sqrt{s} = 8$ TeV, corresponding to an integrated luminosity of 11.4 fb$^{-1}$ collected in 2012 with the ATLAS detector at the LHC. The differential cross-section, assuming unpolarised $J/ψ$ production, is measured as a function of the transverse momentum of the lower-$p_{\mathrm{T}}$ $J/ψ$ meson, di-$J/ψ$ $p_{\mathrm{T}}$ and mass, the difference in rapidity between the two $J/ψ$ mesons, and the azimuthal angle between the two $J/ψ$ mesons. The fraction of prompt pair events due to double parton scattering is determined by studying kinematic correlations between the two $J/ψ$ mesons. The total and double parton scattering cross-sections are compared with predictions. The effective cross-section of double parton scattering is measured to be $σ_{\mathrm{eff}} = 6.3 \pm 1.6 \mathrm{(stat)} \pm 1.0 \mathrm{(syst)}$ mb.

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ATLAS Collaboration. 2017-02-19. Measurement of the prompt $J/ψ$ pair production cross-section in $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector. https://doi.org/10.1140/epjc%2Fs10052-017-4644-9

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