Determination of complete experiments using graphs
Keywords:Hadron spectroscopy, baryon espectroscopy, photonuclear reactions, amplitude-extraction problems, polarization observables, complete experiments, Moravcsik graphs
This work presents ideas for the determination of complete experiments using graphs, which are based on a recently published, modified form of Moravcsik’s theorem. The lucid representation of complete experiments in terms of graphs, which is at the heart of the theorem, leads to a fully automated procedure that can determine complete experiments for in principle any reaction, i.e. for any number of amplitudes N . For larger N (i.e. N ≥ 4), the sets determined according to Moravcsik’s theorem turn out to be slightly overcomplete. A new type of directional graph has been proposed recently, which can decrease the length of the complete sets of observables in some of these cases. The presented results are relevant for reactions with larger numbers of spin-amplitudes, which are at the center of interest in forthcoming measurements, such as single-meson electroproduction (N = 6), two-meson photoproduction (N = 8) or vector-meson photoproduction (N = 12).
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