Decay of a Resonance in ¹⁸Ne by the Simultaneous Emission of Two Protons

Radioactive ion beams of ¹⁷F were used to study several resonance states in ¹⁸Ne. Clear evidence for simultaneous two-proton emission from the 6.15 MeV state (J^π  =  1^-) in ¹⁸Ne has been observed with the reaction ¹⁷F+¹H. Because of limited angular coverage, the data did not differentiate between the two possible mechanisms of simultaneous decay, diproton (²He) emission or direct three-body decay. The two-proton partial width was found to be 21±3 eV assuming ²He emission and 57±6 eV assuming three-body decay. The total width of the 1^- state was measured to be 50±5 keV. Several additional resonances that decay by single proton emission were also studied.