Important contributions to the study of the excitation spectra of
baryons are provided by measurements of polarization observables
in reactions that involve particles with spin. Pseudoscalar meson
photoproduction poses an example-reaction that has been under intense
The extraction of resonance-parameters from the polarization-data in
so-called energy-dependent fits, often involving sophisticated reaction-
theories and analyzing several reaction-channels at once, represents
the state-of-the-art method to get to the spectrum. While yielding
important scientific insights, the construction and handling of such
models is very sophisticated.
The analysis of partial waves at single energies in so-called energy-
independent fits represents a simpler problem. However, due to
mathematical ambiguities rising exponentially in number with the amount
of non-zero partial waves, such analyses still require some experience.
In order to obtain first insights into a newly measured polarization
dataset, simpler alternatives are desirable.
This talk will present the very basic method of moment-analysis
for pseudoscalar meson photoproduction, which proceeds by analyzing
just the angular distributions. The order of the dominant partial waves
contributing in the data can be extracted quickly using this method.
Furthermore, the coefficients extracted from the angular distributions
show interesting composition-patterns in terms of multipoles and allow
for instructive comparisons to models.
A survey of recently published polarization data will be given using
This work was supported by the Deutsche Forschungsgemeinschaft (SFB/TR16).