E18/ENE Seminar

A High-Precision Measurement of the Chiral Anomaly at COMPASS

by Dr Dominik Ecker (Technical University Munich)

Europe/Berlin
E18/ENE Seminar Room 3268 (TUM PH)

E18/ENE Seminar Room 3268

TUM PH

Description

When we are dealing with the lightest quarks at low energies, the properties of Quantum Chromodynamics are encoded by chiral symmetry and the manifestation of its breaking. 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. 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, which arise as a consequence of the chiral anomaly. We will review the state of the art, explain previous measurements and point out experimental challenges. We will then highlight the recent measurement of the anomalous value for F by the COMPASS collaboration at CERN. A proposed measurement at the AMBER experiment will allow us to extent the studies to the next heaviest quark generation in interactions with kaons.