ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

This paper reviews and extends searches for the direct pair productionof the scalar supersymmetric partners of the top and bottom quarksin proton--proton collisions collected by the ATLAS collaboration during the LHC Run 1. Most of the analyses use 20 fb$^{-1}$ of collisions at a centre-of-mass energy of $\sqrt{s} = 8$ TeV, although in some case an additional 4.7 fb$^{-1}$ of collision data at $\sqrt{s}= 7$ TeV are used. New analyses are introduced to improve the sensitivity to specific regions of the model parameter space. Since no evidence of third-generation squarks is found, exclusion limits are derived by combining several analyses and are presented in both a simplified model framework, assuming simple decay chains, as well as within the context of more elaborate phenomenological supersymmetric models.