Jet and missing transverse momentum reconstruction in ATLAS at the LHC

The hadronic final state of the proton-proton collisions at the Large Hadron Collider (LHC) at CERN is measured with the ATLAS detector by reconstructing jets and the missing transverse momentum ($E_{\text{T}}^{\text{miss}}$). Both jet and $E_{\text{T}}^{\text{miss}}$ reconstruction during LHC Run 2 (2015-2018), where the protons were collided with a centre-of-mass energy of $\sqrt{s} = 13\,\text{TeV}$, faced significant challenges due to the high beam intensities that introduced the highest level of pile-up so far. Selected results from the evaluation of the jet and $E_{\text{T}}^{\text{miss}}$ reconstruction performances are presented. Notably, the achieved precision of the jet energy measurement is about 1% over a large fraction of the accessible phase space for both narrow and wide jets, thus preserving the precision reached in previous LHC operations with significantly lower pile-up.