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 = 8 TeV with the ATLAS detector.

The associated production of vector boson with heavy quarkonia is a key observable for understanding the quarkonium production mechanisms. In this poster we present the first evidence of the production of the Z boson in asso- ciation with a prompt and non-prompt J/ψ meson and measure its production rate in comparison of the inclusive Z production. Relative contributions to the signal from single and double parton scattering are estimated. We compare sin- gle parton scattering cross-sections to cutting-edge theoretical calculations in the colour singlet and colour octet formalisms. Finally, we extract a lower limit in the double parton scattering effective cross section.