Search for a Neutral Weak Interaction viaν¯eDissociation of Deuterons

Abstract

An attempt was made to observe the dissociation of the deuteron by electron antineutrinos in order to test the theory of the neutral weak-interaction current. This event could be recognized by the detection of both disintegration products, the neutron and the proton. A deuterated liquid scintillator loaded with gadolinium to provide energetic-neutron-capture $\gamma$ rays was used in this search. The signature for the event would be a prompt "proton" pulse followed by a coincidence between two crystals which signaled neutron capture. The crystal energy gates were set between 0.75 and 6.25 MeV, and the liquid scintillator was set for a light output equal to that produced by electrons >0.20 MeV and ${10}^{-42\mathrm{}}$ ${\mathrm{cm}}^2$, a limit which is to be compared with a maximum theoretical expectation of 1.3×${10}^{-44\mathrm{}}$ ${\mathrm{cm}}^2$ and a previous experimental limit of ${10}^{-40\mathrm{}}$ ${\mathrm{cm}}^2$.