Driving missing data at the LHC : NNLO predictions for the ratio of γ + j and Z + j.

In this paper, we present a calculation of the γ+j process at next-to-next-to-leading order (NNLO) in QCD and compare the resulting predictions to 8 TeV CMS data. We find good agreement with the shape of the photon pT spectrum, particularly after the inclusion of additional electroweak corrections, but there is a tension between the overall normalization of the theoretical prediction and the measurement. We use our results to compute the ratio of Z(→ℓ+ℓ−)+j to γ+j events as a function of the vector boson transverse momentum at NNLO, a quantity that is used to normalize Z(→νν¯)+j backgrounds in searches for dark matter and supersymmetry. Our NNLO calculation significantly reduces the theoretical uncertainty on this ratio, thus boosting its power for future searches of new physics