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Measurements of event shapes and azimuthal correlations are presented for events where a Z boson is produced in association with jets in proton-proton collisions. The data collected with the CMS detector at the CERN LHC at s=7 TeV correspond to an integrated luminosity of 5.0 fb−1. The analysis provides a test of predictions from perturbative QCD for a process that represents a substantial background to many physics channels. Results are presented as a function of jet multiplicity, for inclusive Z boson production and for Z bosons with transverse momenta greater than 150 GeV, and compared to predictions from Monte Carlo event generators that include leading-order multiparton matrix-element (with up to four hard partons in the final state) and next-to-leading-order simulations of Z+1-jet events. The experimental results are corrected for detector effects, and can be compared directly with other QCD models.
Chatrchyan, S., Khachatryan, V., Sirunyan, A. M., Tumasyan, A., Adam, W., Aguilo, E., … Swanson, J. (2013). Event shapes and azimuthal correlations in Z+jets events in pp collisions at s=7 TeV. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 722(4–5), 238–261. https://doi.org/10.1016/j.physletb.2013.04.025