Study of Non-strange Dibaryon Resonances Via Coherent Double Neutral-Meson Photoproduction from the Deuteron

Abstract

The non-strange (formula presented) system (dibaryon) has been studied using coherent neutral-meson photoproduction from the deuteron, (formula presented) and (formula presented), measured with the FOREST detector at the ELPH facility. A rather flat angular distribution of deuteron emission and a peak in the (formula presented) invariant-mass distribution give evidence for the 2.15-GeV isovector dibaryon. The excitation function of the total cross section as a function of the (formula presented) center-of-mass energy for the former reaction shows the evidence for the existence of 2.47- and 2.63-GeV isoscalar dibaryons.