My research revolves about one of the key questions in the Standard Model of particle physics: why is the electroweak symmetry broken and how exactly does the spontaneous symmetry breaking occur? While the discovery of the Higgs boson marks a milestone in this area, it leaves us with many mysteries awaiting discovery. I am a member of the StandUP research group at DESY.

CMS Collaboration

The key ingredients in electroweak symmetry breaking are the heaviest known fundamental particles, the W, Z and H bosons and the top quark. With the team at DESY we are studying rare processes where these particles are produced at the LHC, sometimes in pairs or in association with other standard model particles. I am involved in various searches for deviations from the Standard Model predictions when these particles are produced, which could lead to discoveries of unknown particles or interactions. I am also working on the identification of boosted heavy resonances (vector boson or top tagging) and measurements of top quark properties. We are using one of the largest experiments in the world, the CMS experiment at the CERN LHC.

Gfitter

Together with my collaborators from the Gfitter group, I am working on the global electroweak fit. We interprete measurements in the context of the Standard Model, thereby assessing the theory’s internal consistency. This leads to very accurate predictions which help to constrain the theory’s free parameters, but also extensions of the Standard Model. An important and novel ingredient to the fit are precision measurements of the Higgs boson couplings, which we study in the context of the Standard Model, effective field theories and new physics models like the two-Higgs-doublet model.

Boosted heavy object tagging

We are developing new methods for the identification of boosted heavy particles decaying hadronically, where the decay products are merged into single jets. The separation of these jets from the vast amount of background jets originating from light quarks or gluons is a challenging task. Developments in this area are based on detailed experimental and theoretical understanding of the substructure of  jets, and improve the performance of data analyses at the LHC. I am working on performance studies of tagging algorithms in CMS and the development of new techniques.

DESY

My research is carried out at the Deutsches Elektronen Synchrotron DESY where I am a member of the CMS group. We work in close collaboration with theoretical and experimental particle physics groups at DESY and the University of Hamburg. I am a member of the Quantum Universe Cluster of Excellence.