Measurements of the chiral anomaly at COMPASS in γπ→ππ and γπ→πη processes

by Andrii Maltsev

Thursday 2 Jul 2026, 14:30 → 15:30 Europe/Berlin

E18/ENE Seminar Room 3268 (TUM PH)

The chiral symmetry and the chiral anomaly are among the fundamental properties of QCD. They can be exploited to build an effective field theory, the chiral perturbation theory (ChPT), that yields the predictions for light meson interactions in the low-energy region, where a perturbative expansion in the strong coupling constant is no longer possible.

Tests of such models based on the chiral anomaly, for example, the γπ→ππ and γπ→πη processes, are important for the understanding and verification of low-energy meson interactions. Experimentally, these processes can be accessed in so-called Primakoff processes, where a particle interacts with a quasi-real photon from the Coulomb field of a heavy nucleus.

This talk will feature the comparison of the γπ→ππ and γπ→πη processes, the current experimental status of the chiral anomaly measurement, and the additional experimental challenges in extracting the anomalous process from the collected ηπ sample.