Sensitivity to WIMP Dark Matter in the Final States Containing Jets and Missing Transverse Momentum with the ATLAS Detector at 14 TeV LHC

This document presents a study of the sensitivity of the ATLAS mono-jet search to pair production of WIMP Dark Matter with $pp$ collision data at $\sqrt{s}=14\,$TeV in 2015 and beyond. Two different classes of models are investigated: the Effective Field Theory employed in previous ATLAS mono-jet results and simplified models with an explicit light mediator. It is shown based on Monte Carlo simulations that the search will quickly surpass previous mono-jet limits within the first year of data-taking and its reach may be further doubled with respect to the first year of running when considering the full expected dataset from the High-Luminosity LHC corresponding to $3000\,$fb$^{-1}$. Limitations of the Effective Field Theory approach are discussed in the context of the energies reached at the LHC.