Garchinger Maier-Leibnitz-Kolloquium: Chiral symmetry breaking: experimental status and prospects

by Dr Dominik Ecker (Physik-Department E18, TUM)

Thursday 7 Dec 2023, 16:15 → 17:15 Europe/Berlin

Lecture Hall, ground floor (west) (LMU building, Am Coulombwall 1, campus Garching)

The interaction of quarks and hadrons is described by  Quantum Chromodynamics (QCD). When we are dealing with the lightest quarks at low energies, the properties of QCD are encoded by chiral symmetry and the manifestation of its breaking. This symmetry breaking is reflected in the spectrum of light hadrons. We can exploit this symmetry to build an effective field theory, which can be expanded as a perturbation theory. Chiral Perturbation Theory allows to describe a variety of phenomena observed for light mesons at low-energies, including their decays and their couplings to photons or other matter fields. Among the light hadrons, the pion plays a special role, as it is the lightest meson and emerges as a Goldstone boson from the breaking of the Chiral Symmetry. Thus, its properties are directly related to the underlying symmetry.

In this talk, we will focus on the experimental verification of pion properties, in particular so-called anomalous couplings. We will review the state of the art, explain previous measurements and point out experimental challenges. We will then highlight recent measurements by the COMPASS collaboration at CERN and discuss the potential of this data set for further measurements. The forthcoming AMBER experiment will allow to extend the studies to the next heaviest generation of quarks by studying the interactions of kaons with high precision.

Hybrid access via ZOOM:
https://lmu-munich.zoom.us/j/98457332925?pwd=TWc3V1JkSHpyOTBPQVlMelhuNnZ1dz09
Meeting ID: 984 5733 2925
Passcode: 979953

kolloquium-07-12-23.pdf