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Title: Observation and measurements of the production of prompt and non-prompt J/ψ mesons in association with a Z boson in pp collisions at √s = 8TeV with the ATLAS detector

The production of a Z boson in association with a J/ψ meson in proton–proton collisions probes the production mechanisms of quarkonium and heavy flavour in association with vector bosons, and allows studies of multiple parton scattering. Using 20.3 fb-1 of data collected with the ATLAS experiment at the LHC in pp collisions at √s=8TeV, the first measurement of associated Z + J/ψ production is presented for both prompt and non-prompt J/ψ production, with both signatures having a significance in excess of 5σ. The inclusive production cross-sections for Z boson production (analysed in μ+μ- or e+e- decay modes) in association with prompt and non-prompt J/ψ( → μ+μ-) are measured relative to the inclusive production rate of Z bosons in the same fiducial volume to be (36.8 ± 6.7 ± 2.5) × 10-7 and (65.8 ± 9.2 ± 4.2) × 10-7 respectively. Normalised differential production cross-section ratios are also determined as a function of the Jψ transverse momentum. As a result, the fraction of signal events arising from single and double parton scattering is estimated, and a lower limit of 5.3 (3.7) mb at 68 (95)% confidence level is placed on the effective cross-section regulating double parton interactions.
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Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC02-06CH11357; AC02-05CH11231; SC00112704; AC03-76SF00515
Accepted Manuscript
Journal Name:
European Physical Journal. C, Particles and Fields
Additional Journal Information:
Journal Volume: 75; Journal Issue: 229; Journal ID: ISSN 1434-6044
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Contributing Orgs:
Atlas Collaboration
Country of Publication:
United States