Research

 

CMS Experiment - Higgs Boson

CMS Event Display Copyright: CMS - CERN Event in the CMS experiment

The CMS experiment at CERN investigates the structure of matter with the world's largest particle accelerator, the Large Hadron Collider (LHC). Our research group which was founded in 2018 (press release) investigates the elusive properties of the Higgs Boson.

In particular the coupling of the Higgs Boson to so-called charm quarks is of high interest, but it is not accessible today. With newly developed tools and methods, using new machine learning techniques, we expect first results on the Higgs-charm coupling measurement in the coming years.

We offer the possibility for Bachelor and Master projects, as well as PhD thesis in this field of research.

NEWS: Discovery of the Higgs decay into in b-quarks: press release

Jet Flavour Identification

An important tool for the identification of the origin of so-called Jets is "flavour tagging". The properties of long-lived particles within jets are exploited for this purpose. For instance, jets originating from b-quarks contain a secondary decay vertex which can be identified using dedicated methods for pattern recognition. The challenge is to identify a decay length of a few micrometers using one of the largest particle detectors every built. Our group develops these methods with a focus on the identification and reconstruction of charm quark jets.

 

MADMAX Experiment - Axions and Dark Matter

MADMAX Copyright: Max Planck Institut München MADMAX test setup

The goal of the Magnetized Disc and Mirror Axion experiment (MADMAX) is to obtain a sensitivity that would allow the discovery of a new particle, the so called axion. The axion is a hypothetical particle that could solve two central problems of physics simultaneously: the nature of dark matter as well as the absence of CP violation in the strong interaction.

From astronomical and astrophysical observations we know precisely that only 5% of the energy in the universe can be explained with the known type of matter. The rest consists of Dark Matter and Dark Energy whose nature is currently still unknown. The theory that Dark Matter could consist of Axion particles is an attractive explanation since several decades.

The underlying theory foundations for the prediction of axions have been laid already in 1977 in a completely different context: to explain the absence of CP-violation (in a broader sense "mirror symmetry") in the strong nuclear interaction. Today we understand that these Axions could solve more mysteries of physics, in particular the nature of Dark Matter. Experimental evidence for this hypothesis has not been found yet.

The planned MADMAX experiment will search for these Axion particles using a "dielectric haloscope". The principle of the experiment is that Axions can create electromagnetic radiation at the transition between two non-conducting media (dielectric media). The power of this electromagnetic emission needs to be enhanced by several orders of magnitudes to make it observable. For this purpose several dielectric discs are placed in a resonator arrangement so that constructive interference and resonance occurs.

A press release has recently made these plans available to the public.