Triangle singularity in the γp → pπ0η reaction ??

Abstract

The γp → pπ0η reaction has been studied with the CBELSA/TAPS detector system to search for experimental evidence for triangle singularities. Kinematically these singularities exist in the decay chain Δ* → ηΔ(1232) → ηπ0 p but do not show an experimental effect because of the weakness of the π0 − η interaction at low s\sqrt s near threshold far below the a0(980) resonance.