New narrow N*(1685) resonance: Review of observations

Abstract

The recent Review of Particle Physics [1] includes a new narrow N*(1685) resonance. Its properties, the narrow width (Γ < 25 MeV) and the strong photoexcitation on the neutron, are unusual. The paper reviews experimental data which have led to the evidence for this resonance. Alternative explanations of the phenomenon at W ∼ 1.685 GeV, namely the interference of well-known resonances and the sub-threshold meson-baryon production, are discussed as well.