Naslov
Pole positions and residues from pion photoproduction using the Laurent-Pietarinen expansion method

Autori
Švarc, Alfred ; Hadžimehmedović, Mirza, Osmanović, Hedim ; Stahov, Jugoslav ; Tiator, Lothar ; Workman, Ron

Izvornik
Physical Review C - Nuclear Physics (0556-2813) 89 (2014); 065208-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
baryon resonances ; poles ; Laurent+Pietarinen expansion

Sažetak
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 GeorgeWashington University SAID (GWU-SAID) groups.We show that the number and properties of poles extracted from photoproduction data correspond very well to results from πN 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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA