2014/04/06 by A. Švarc, Alfred Švarc, M. Hadžimehmedović +8 · 1 citation
Mathematics · Physics and Astronomy · #Amplitude #Laurent series #Mathematical analysis #Mathematics #Multipole expansion #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics of Superconductivity and Magnetism #Pion #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Representation (politics) #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevc.89.065208
published as Phys. Rev. C 89, 065208 (2014) · 23 pages, 5 figures, 9 tables. arXiv admin note: text overlap with arXiv:1401.1947
arxiv created 2014/04/06 · openalex publication_date 2014/06/20 · arxiv updated 2014/06/25 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We applied a new approach to determine the pole positions and residues from pion photoproduction multipoles. The method is based on a Laurent expansion of the partial-wave T matrices, with a Pietarinen series representing the regular part of energy-dependent and single-energy photoproduction solutions. The method is applied to multipole fits generated by the MAID and George Washington University SAID (GWU-SAID) groups. We show that the number and properties of poles extracted from photoproduction data correspond very well to results from \ensuremathπN elastic data and values cited by the Particle Data Group (PDG). The photoproduction residues provide new information for the electromagnetic current at the pole position, which are independent of background parametrizations, which is not the case for the Breit-Wigner representation. Finally, we present the photodecay amplitudes from the current MAID and SAID solutions at the pole for all four-star nucleon resonances below W=2 GeV.