Abstract
The performance of the missing transverse momentum (Emiss
) reconstruction with the ATLAS
detector is evaluated using data collected in proton–proton collisions at the LHC at a centre-
of-mass energy of 13 TeV in 2015. To reconstruct Emiss, fully calibrated electrons, muons, photons,
hadronically decaying τ-leptons, and jets reconstructed from calorimeter energy deposits and
charged-particle tracks are used. These are combined with the soft hadronic activity measured by
reconstructed charged-particle tracks not associated with the hard ob- jects. Possible double
counting of contributions from reconstructed charged-particle tracks from the inner detector,
energy deposits in the calorimeter, and reconstructed muons from the muon spectrometer is avoided
by applying a signal ambiguity resolution procedure which rejects already used signals when
combining the various Emiss contributions. The individual terms as well as the overall
reconstructed Emiss are evaluated with various performance met- rics for scale (linearity),
resolution, and sensitivity to the data-taking conditions. The method developed to determine the
systematic uncertainties of the Emiss scale and resolution is dis- cussed. Results are shown based
on the full 2015 data sample corresponding to an integrated luminosity of 3.2 fb−1.