Research > Particle Physics

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Flavour Physics

(Rare B and kaon decays, Unitarity Triangle Phenomenology)

Top Physics

The top quark is the most heavy of the six quarks, it was discovered in 1995 at the Fermilab Tevatron. Owing to its large mass, it is believed to be closely related to the mechanism of mass generation and electroweak symmetry breaking in particle physics.
The precise study of top quark production and decay will be one of the principal objectives at the CERN LHC collider and at a future International Linear Collider (ILC).
Our research activities on top quark physics involve the calculation of QCD corrections to the top quark production cross section at the LHC and to the electroweak production asymmetry at the ILC.

Supersymmetry (MSSM Phenomenology)

The breaking of the high-energy symmetry between electromagnetic and weak interactions though the Higgs mechanism introduces several anomalies, which point towards physics beyond the standard model.
A particular scenario of this is supersymmetry (SUSY), which eliminates the anomalies from the Higgs section and predicts SUSY partners for all known particles. The minimal formulation of SUSY is the minimal supersymmetric standard model (MSSM).
Our research activities focus on SUSY signatures in rare decays of heavy quarks, in neutrino interactions or through direct SUSY particle production at high energy colliders.

Soft-Collinear Effective Theory
Perturbative QCD

Quark and gluon interactions are described by the theory of quantum chromodynamics (QCD). For energies well above the bound state energy of the proton this theory can be expanded in a perturbative series, allowing precise predictions to be compared to experimental data.
The most prominent QCD observables are jet production cross sections, which are measured very precisely at high energy colliders.
Our work aims towards a precise prediction of jet production and internal jet structure using perturbative QCD.

Computer Algebra in QFT

The analytic determination of higher order corrections in perturbative quantum field theory requires extensive use of computer algebra.
Computer algebra programmes auch as FORM, Mathematica or Maple are used to manage the large number of contributing diagrams, and to evaluate the highly involved loop integrals appearing in them.
Current computer algebra projects involve multi-loop corrections to four-point functions and to vertex form factors. These allow precise QFT predictions for a wide range of observables, including jet physics and rare decays of heavy quarks.

Collider Physics

High energy hadron colliders (Fermilab Tevatron and CERN LHC) allow to probe elementary particle interactions at energies high enough to produce very heavy short-lived particles, such as top quarks and electroweak vector bosons.
Likewise, they will allow to discover yet unobserved particles postulated in particle theory, such as the Higgs boson,supersymmetric partners of known particles or more exotic phenomena.
Research carried out here investigates propects for searching new phenomena at hadron colliders, as well as their implications for astrophysics and cosmology