Ecker, D. (2024) Testing predictions of the chiral anomaly in Primakoff reactions at COMPASS. Il nuovo cimento C, 47 (4). pp. 1-5. ISSN 1826-9885
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Abstract
The chiral anomaly is a fundamental property of quantum chromodynamics (QCD). It governs the transition amplitudes for processes involving an odd number of Goldstone bosons of chiral symmetry breaking. In case of the coupling of three pions to a photon, the magnitude of the resulting coupling is F3π and the value is predicted by chiral perturbation theory with small uncertainty. It can experimentally be measured in π−γ → π−π0 scattering. Here, we report on a precision experiment on F3π using the COMPASS experiment at CERN where pion-photon scattering is mediated via the Primakoff effect using heavy nuclei as target. We exploit the interference of the production of the π−π0 final state via the chiral anomaly with the photo-production of the ρ(770) resonance over a wide mass range Mπ−π0 < 1 GeV/c2. This is in contrast to previous measurements restricting themselves only to the threshold region Mπ−π0 < 370 MeV. Our analysis allows to simultaneously extract the radiative width of the ρ(770) resonance and gives a stronger handle on F3π in a unified approach thereby minimizing systematic effects rarely addressed previously.
| Item Type: | Article |
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| Subjects: | 500 Scienze naturali e Matematica > 530 Fisica |
| Depositing User: | Marina Spanti |
| Date Deposited: | 23 Sep 2024 11:51 |
| Last Modified: | 23 Sep 2024 11:51 |
| URI: | http://eprints.bice.rm.cnr.it/id/eprint/23184 |
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