Speaker
Jonas Müller
(Universität Bonn)
Description
One of the open challenges in subnuclear physics is to understand the nonperturbative regime of Quantum chromodynamics, including the world of the nucleon and its excitations. In order to extract the contributing baryon resonances in photoproduction experiments, partial wave analyses need to be performed. A complete experiment is required to unambiguously determine the contributing amplitudes. This involves the measurement of carefully chosen single and double polarisation observables. With the Crystal-Barrel/TAPS experiment at ELSA measurements of polarisation observables are possible for different reactions by using a circularly or linearly polarised photon beam and a longitudinally or transversely polarised frozen spin butanol target. The Crystal-Barrel/TAPS setup provides a nearly 4\pi angular coverage, a good energy resolution, and a high detection efficiency for photons and is therefore ideally suited to study final states comprising neutral mesons. In this talk results for the measurement of the double polarisation observable E in the reactions \vec{\gamma} \vec{p} \to p \pi^0 and \vec{\gamma} \vec{p} \to p \eta will be presented.
Supported by the DFG (SFB/TR16).
Primary author
Jonas Müller
(Universität Bonn)