The European Physical Journal C > 2017 > 77 > 2 > 1-34
Measurement of the prompt J/ $$\psi $$ ψ pair production cross-section in pp collisions at $$\sqrt{s} = 8$$ s = 8 TeV with the ATLAS detector
Source
Abstract
The production of two prompt $$J/\psi $$ J / ψ mesons, each with transverse momenta $$p_{\mathrm {T}}>8.5$$ p T > 8.5 GeV and rapidity $$|y| < 2.1$$ | y | < 2.1 , is studied using a sample of proton-proton collisions at $$\sqrt{s} = 8$$ s = 8 TeV, corresponding to an integrated luminosity of 11.4 fb $$^{-1}$$ - 1 collected in 2012 with the ATLAS detector at the LHC. The differential cross-section, assuming unpolarised $$J/\psi $$ J / ψ production, is measured as a function of the transverse momentum of the lower- $$p_{\mathrm {T}}$$ p T $$J/\psi $$ J / ψ meson, di- $$J/\psi $$ J / ψ $$p_{\mathrm {T}}$$ p T and mass, the difference in rapidity between the two $$J/\psi $$ J / ψ mesons, and the azimuthal angle between the two $$J/\psi $$ J / ψ mesons. The fraction of prompt pair events due to double parton scattering is determined by studying kinematic correlations between the two $$J/\psi $$ 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 $$\sigma _{\mathrm {eff}} = 6.3 \pm 1.6 \mathrm {(stat)} \pm 1.0 \mathrm {(syst)}$$ σ eff = 6.3 ± 1.6 ( stat ) ± 1.0 ( syst ) mb.
Identifiers
journal ISSN : | 1434-6044 |
journal e-ISSN : | 1434-6052 |
DOI | 10.1140/epjc/s10052-017-4644-9 |