CMS_2013_I1258128
Rapidity distributions are presented for events containing either a $Z$ boson or a photon in association with a single jet in proton-proton collisions produced at the CERN LHC. The data, collected with the CMS detector at $\sqrt{s} = 7$ TeV, correspond to an integrated luminosity of 5.0/fb. The individual rapidity distributions of the boson and the jet are consistent within 5\% with expectations from perturbative QCD. However, QCD predictions for the sum and the difference in rapidities of the two final-state objects show significant discrepancies with CMS data. In particular, next-to-leading-order QCD calculations, and two Monte Carlo event generators using different methods to merge matrix-element partons with evolved parton showers, appear inconsistent with the data as well as with each other.
