Coherent $\pi^0\eta d$ photoproduction at forward deuteron angles measured at BGOOD

• DOI: 10.48550/arxiv.2405.09392
• Publication Date: 2024-05-15
• Authors: Antonio Joao Clar...; T. C. Jude; S. Alef; P. L. Cole; R. Di Salvo; D. Elsner; A. Fantini; O. Freyermuth; F. Frommberger; F. Ghio; Jürgen H. Gross; Katrin Kohl; P. Levi Sandri; G. Mandaglio; P. Pedroni; B. -E. Reitz; M. Romaniuk; G. Scheluchin; H. Schmieden; A. Sonnenschein; C. Tillmanns
• Keywords: FOS: Physical sciences; Nuclear Experiment (nucl-ex); Nuclear Experiment

The coherent reaction, $\gamma d \rightarrow \pi^0\eta d$ was studied with the BGOOD experiment at ELSA from threshold to a centre-of-mass energy of 3200\,MeV. A full kinematic reconstruction made, final state deuterons identified in forward spectrometer and $\pi^0$ $\eta$ decays central BGO Rugby Ball. strength differential cross section exceeds what can be described by models photoproduction angles orders magnitude. distribution has an excellent agreement model including quasi-free $\Delta \pi$ photoproduction, pion re-scattering $N(1535)$ formation subsequent nucleon coalescence deuteron. This also gives reasonable description two-body invariant mass distributions naturally explains similar magnitudes this channel $\pi^0\pi^0 photoproduction.