Precise predictions for [Formula: see text] jets dark matter backgrounds

High-energy jets recoiling against missing transverse energy (MET) are powerful probes of dark matter at the LHC. Searches based on large MET signatures require a precise control of the [Formula: see text] jet background in the signal region. This can be achieved by taking accurate data in control regions dominated by [Formula: see text] jet, [Formula: see text] jet and [Formula: see text] jet production, and extrapolating to the [Formula: see text] jet background by means of precise theoretical predictions. In this context, recent advances in perturbative calculations open the door to significant sensitivity improvements in dark matter searches. In this spirit, we present a combination of state-of-the-art calculations for all relevant [Formula: see text] jets processes, including throughout NNLO QCD corrections and NLO electroweak corrections supplemented by Sudakov logarithms at two loops. Predictions at parton level are provided together with detailed recommendations for their usage in experimental analyses based on the reweighting of Monte Carlo samples. Particular attention is devoted to the estimate of theoretical uncertainties in the framework of dark matter searches, where subtle aspects such as correlations across different [Formula: see text] jet processes play a key role. The anticipated theoretical uncertainty in the [Formula: see text] jet background is at the few percent level up to the TeV range.