Present Limits on the Precision of SM Predictions for Jet Energies

7 We investigate the impact of theoretical uncertainties on the accuracy of measurements involving hadronic jets. The analysis is performed using events with a Z boson and a single jet observed in pp̄ collisions at √ s = 1.96 TeV in 4.6 fb of data from the Collider Detector at Fermilab (CDF). The transverse momenta (pT) of the jet and the boson should balance each other due to momentum conservation in the plane transverse to the direction of the p and p̄ beams. We evaluate the dependence of the measured pT-balance on theoretical uncertainties associated with initial and final state radiation, choice of renormalization and factorization scales, parton distribution functions, jet-parton matching, calculations of matrix elements, and parton showering. We find that the uncertainty caused by parton showering at large angles is the largest amongst the listed uncertainties. The proposed method can be re-applied at the LHC experiments to investigate and evaluate the uncertainties on the predicted jet energies. The distributions produced at the CDF environment are intended for comparison to those from modern event generators and new tunes of parton showering. The comparison will allow higher accuracy of the predicted jet energies, and thus an improved discovery potential in signatures containing jets, at the LHC.