TP1 Research Group – Dr. Björn Lange
My main research is the development and application of theoretical tools to describe a broad variety of collider-based physics processes, such as weak flavour transitions in e.g. B decays, CP violation, and processes involving culminated jets of hadrons. The goal is to more precisely understand the predictions from the Standard Model, in particular from QCD, and the effects of possible extensions of the Standard Model.
Effective field theories such as Heavy-Quark Effective Theory and Soft-Collinear Effective Theory provide frameworks that allow for the resummation of large logarithms with renormalization-group methods. We derive these techniques and apply them to achieve unprecedented accuracy in theoretical predictions of the processes mentioned above.
The phenomenological studies of rare flavour transitions, particularly of the bottom and charm quarks, are an ongoing activity in which we are closely collaborating with our experimental colleagues at SLAC, KEK, and LHCb.
While accurate Standard Model predictions allow for indirect searches for new physics — where Nature deviates from our current description –, direct searches are particularly interesting for processes that are forbidden or extremely rare within the Standard Model. Examples that interest us are Lepton-Number violating or Lepton-Flavour violating processes that are mediated by higher dimensional operators added to the Standard Model.