With the start of the Large Hadron Collider (LHC) which will explore a complete new energy regime important discoveries lie ahead of us. It is perhaps the most exciting time in elementary particle physics since the start of the Large Electron Positron collider twenty years ago.
To discover old and new physics at the LHC, precise theoretical predictions are necessary to which the experimental data has to be compared. In the context of perturbation theory the required accuracy enforces to go beyond the Born approximation. Owing to the complicated environment---in particular the appearance of many strongly interacting particles---the required next-to-leading order calculations are highly non-trivial. These calculations are crucial for the success of the physics program at the LHC. One focus of the research of the Helmholtz Young Investigator Group at the Humboldt University Berlin is
- to apply existing methods for one-loop calculations to derive results for phenomenologically important processes like top-quark production, gauge boson production and Higgs production
- to investigate new methods avoiding the growth in complexity of traditional methods based on Feynman diagrams
- the further development of automatizing next-to-leading order cross section calculations for LHC
LHC offers also the possibility to measure the top-quark properties with an unprecedent accuracy. This allows us to study the fundamental question whether the top-quark is just an accidently rather heavy copy of the lighter quarks or whether it plays a special role as suggested in many possible extensions of the standard model. Top-quark physics is a another research field of the group. Important topics are
- The refinement of the theoretical predictions to match the experimental uncertainties
- The investigation of new observables allowing more detailed tests of top-quark properties
- Top-quark physics as a standard candle and a special laboratory for testing quantum chromodynamics the theory of strong interactions
The aforementioned research relies on massive use of computers. The development and application of analytical and numerical methods is a further activity of the group.