Looking For SUSY
Cem Salih Un
Abstract: The Standard Model (SM) of the elementary particles is one of the most successful theory in physics. Its last triumph is observation of the Higgs Boson in the ATLAS and CMS experiments. Even though the observations has confirmed so far that the Higgs boson has the properties for its production and decay modes as predicted by the SM decades ago, its mass is problematic in the SM as is known for a long time. The observed mass of it is about 125 GeV which is slightly below the mass required by the absolute Higgs vacuum stability. Besides the observations, the SM cannot stabilize its mass consistently with the electroweak symmetry breaking scale due to divergent loop contributions to the Higgs mass. Considering such problems, despite its success, there is no doubt that the SM is not a fundamental theory, but it is rather an effective theory valid up to an energy scale at the order of TeV. In this context, a fundamental theory needs to have a larger structure which can be built by extending the SM by adding new ingredients. In such theories beyond the SM, the path should end up with the SM, since its implications are almost in a perfect agreement with the experimental results.
Supersymmetry (SM) is arguably the most compelling candidate, and minimal supersymmetric extension of the SM (MSSM) can resolve the stability problem in the Higgs boson mass, unify all the three gauge couplings at the grand unification scale (MGUT ~ 1016 GeV), provide pleasant candidates for the dark matter and so on. In spite of the strong motivations, the stringent constraints play on the supersymmetric models. The current status of the Large Hadron Collider (LHC) is capable of conducting highly sensitive searches for the SUSY particles, and there has been no signal returning that could confirm the existence of such particles, even though MSSM is mostly consistent with the current Higgs boson observations.
In this talk, the SM and its minimal supersymmetric extension MSSM will be briefly described. After reviewing the experimental constraints, the current status of supersymmetric models will be considered in the light of such constraints.