Search for New Physics in Mono-jet Final States in pp Collisions at √s = 13 TeV with the ATLAS Experiment at the LHC

Many cosmological observations indicate that the matter predicted and described by the Standard Model constitutes only a small fraction of the entire known universe. These astrophysics measurements infer the existence of Dark Matter which is constituted by beyond the Standard Model particles. Among the possible different approaches to search this kind of particles, in this thesis a detailed description of the mono-jet analysis is addressed in which final states with high transverse momentum and an energetic hadronic jet needed to tag the events are considered. The results presented are based on the full dataset recorded in 2015 in the ATLAS experiment at the centre of mass energy of colliding protons of 13 TeV at LHC. The level of agreement observed between data and Standard Model predictions is interpreted as limits in different theoretical contexts, such as compressed supersymmetric models, theories which foresee extra-spatial dimensions, and in the Dark Matter scenario. In the latter, the limits are then compared with the ones obtained by other ATLAS analyses and by experiments based on completely different experimental techniques. Finally, a set of possible analysis improvements is introduced in order to reduce the main uncertainties which affect the signal region and to increase the discovery potential by exploiting further the information of the final state.