Engineering topics

Meißner, U. -G.

Publications and source records attributed to Meißner, U. -G..

2 records

DOE OSTI2022

Light baryon resonances from a coupled-channel study including $$\mathbf {K\Sigma }$$ photoproduction

The Jülich-Bonn dynamical coupled-channel approach is extended to include KΣ photoproduction off the proton. Differential cross section and (double) polarization data for K + Σ 0 and K 0 Σ + are analysed simultaneously with the pion- and photon-induced production of πN, ηN, KΛ, and KΣ final states, totaling almost 72,000 data points for center-of-mass energies W<2.4 GeV. Based on the fit results the spectrum of N * and Δ resonances is extracted in terms of pole positions and residues. We discuss the impact of the γp→KΣ channels in detail and investigate the influence of recent polarization data for ηp photoproduction.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2020

Observation of the p η ' Cusp in the New Precise Beam Asymmetry Σ Data for γ p → p η

Data on the beam asymmetry Σ in the photoproduction of η mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range from W = 1748 MeV to W = 2045 MeV). The data cover the full solid angle that allows for a precise moment analysis. For the first time, a strong cusp effect in a polarization observable has been observed that is an effect of a branch-point singularity at the pη' threshold [E γ = 1447 MeV (W = 1896 MeV)]. Here, the latest BnGa partial wave analysis includes the new beam asymmetry data and yields a strong indication for the N(1895)1/2 – nucleon resonance, demonstrating the importance of including all singularities for a correct determination of partial waves and resonance parameters.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗