New Physics at the Large Hadron Collider

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The Large Hadron Collider (LHC) at CERN is the flagship research facility of particle physics for the next decade. After the discovery of a Higgs particle in the first phase of the LHC in 2012, the key scientific goal for the second phase, starting in 2015, is to search for and explore physics beyond the Standard Model (SM). The existence of new physics at the Tera-electronvolt (TeV) scale, i.e. in reach of the LHC, is motivated by two fundamental questions left unanswered by the SM: the hierarchy problem and the nature of dark matter. The hierarchy problem refers to the instability of the Higgs mass at the electroweak scale under quantum fluctuations originating from high-scale physics. It can be solved, for example, through new TeV-scale particles partnering the SM top quark. Dark matter, on the other hand, is explained naturally by stable, weakly interacting particles with masses near the TeV scale. Such particles are predicted in many extensions of the SM, which attempt to solve the hierarchy problem, like supersymmetry or models with extra space dimensions. At the LHC, new physics can be searched for either directly, for example in signatures with a transverse momentum imbalance caused by escaping dark matter particles, or through precision studies which attempt to establish deviations from the Standard Model in a global theoretical analysis of all existing experimental observables, including in particular the Higgs sector.In the Research Unit ¿New Physics at the LHC¿ we propose to pursue theoretical calculations and analyses of new physics scenarios at the LHC which address the hierarchy problem, the origin of dark matter, or both. They comprise, in particular, precision calculations for the production and decay of new particles, the exploration of the top-Higgs sector and models of dark matter, a systematic study of top-partner and dark matter production and detection at the LHC, and global fits of Higgs properties and new physics models.These theoretical analyses shall provide the basis for the interpretation of new physics searches during the second phase of the LHC, and are crucial in order to fully exploit its potential.