A Genetic Algorithm Analysis of N* Resonances in $p(\gamma,K^{+})\Lambda$ Reactions

摘要

The problem of extracting information on new and known $N^{*}$ resonances byfitting isobar models to photonuclear data is addressed. A new fittingstrategy, incorporating a genetic algorithm, is outlined. As an example, themethod is applied to a typical tree-level analysis of published$p(\gamma,K^{+})\Lambda$ data. It is shown that, within the limitations of thistree-level analysis, a resonance in addition to the known set is required toobtain a reasonable fit. An additional $P_{11}$ resonance, with a mass of about1.9 GeV, gives the best agreement with the published data, but additional$S_{11}$ or $D_{13}$ resonances cannot be ruled out. Our genetic algorithmmethod predicts that photon beam asymmetry and double polarization$p(\gamma,K^{+})\Lambda$ measurements should provide the most sensitiveinformation with respect to missing resonances.