Performance of algorithms that reconstruct missing transverse momentum in $\sqrt{s}=$ 8 TeV proton-proton collisions in the ATLAS detector

Understand

The reconstruction and calibration algorithms used to calculate missing transverse momentum ($E_{\rm T}^{\rm miss}$) with the ATLAS detector exploit energy deposits in the calorimeter and tracks reconstructed in the inner detector as well as the muon spectrometer.

• Various strategies are used to suppress effects arising from additional proton-proton interactions, called pileup, concurrent with the hard-scatter processes.
• Tracking information is used to distinguish contributions from the pileup interactions using their vertex separation along the beam axis.
• The performance of the $E_{\rm T}^{\rm miss}$ reconstruction algorithms, especially with respect to the amount of pileup, is evaluated using data collected in proton-proton collisions at a centre-of-mass energy of 8 TeV during 2012, and results are shown for a data sample corresponding to an integrated luminosity of 20.3 fb$^{-1}$.