Recent ATLAS results and preparations for Run 2

TL;DR

This paper reviews the ATLAS experiment's achievements during Run 1, including Higgs discovery and Standard Model tests, and discusses upgrades and early results from Run 2 at the LHC.

Contribution

It provides a comprehensive summary of the final Run 1 results and details the detector upgrades and preparations for Run 2 at the LHC.

Findings

Discovery of the Higgs boson

Precise measurements of W and Z bosons

Searches for supersymmetry and new phenomena

Abstract

The CERN LHC delivered 25/fb of proton-proton collision data in 2011-2012 at sqrt{s} = 7 - 8 TeV centre-of-mass energy to the ATLAS detector. These Run 1 data were used to discover the Higgs boson and measure its properties as well as to perform numerous other tests of the Standard Model via precision measurements and searches for New Physics. In preparation for the Run 2 data taking at sqrt{s} = 13 TeV, the collaboration embarked on an upgrade program during the long LHC machine shutdown in 2013-2015. The early 2015 data set was then used to promptly recommission the apparatus allowing the first physics results to appear already in the summer of 2015. After briefly reviewing the upgrade and the improved performance of the detector, this paper concentrates on the final Run~1 results on Higgs, W and Z boson, electroweak multi-boson and top quark production as well as on searches for supersymmetry and other new phenomena.