Baryon Spectroscopy - Recent Results from the CBELSA/TAPS Experiment

Abstract

One of the remaining challenges within the standard model is to gain a good understanding of QCD in the non-perturbative regime. One key step toward this aim is baryon spectroscopy, investigating the spectrum and the properties of baryon resonances. To get access to resonances with small $\pi N$ partial width, photoproduction experiments provide essential information. In order to extract the contributing resonances, partial wave analyses need to be performed. Here, a complete experiment is required to unambiguously determine the contributing amplitudes. This involves the measurement of carefully chosen single and double polarization observables. The CBELSA/TAPS experiment with a longitudinally or transversely polarized target and an energy tagged, linearly or circularly polarized photon beam allows the measurement of a large set of polarization observables. Due to its good energy resolution, high detection efficiency for photons, and the nearly complete solid angle coverage it is ideally suited for the measurement of photoproduction of neutral mesons decaying into photons. Recent results for various double polarization observables in ${\pi }^0$ and $\eta$ photoproduction and their impact on the partial wave analysis are discussed.

6 pages, 4 figures, Proceedings of Hadron 2015 conference

References in corpus (9)

• Unitary Isobar Model - MAID2007
• Study of the gp-->etap reaction with the Crystal Ball detector at the Mainz Microtron(MAMI-C)
• Eta photoproduction in a combined analysis of pion- and photon-induced reactions
• High statistics study of the reaction $\gamma p\to p2{\pi }^0$
• Linearly polarised photon beams at ELSA and measurement of the beam asymmetry in pi^0-photoproduction off the proton
• Measurement of the transverse target and beam-target asymmetries in $\eta$ meson photoproduction at MAMI
• First measurement of the helicity asymmetry $E$ in $\eta$ photoproduction on the proton
• The N(1520) 3/2- helicity amplitudes from an energy-independent multipole analysis based on new polarization data on photoproduction of neutral pions
• The polarization observables T, P, and H and their impact on $\gamma p\to p{\pi }^0$ multipoles