Updated Parameters for the Decaying Neutrino Theory and EURD Observations of the Diffuse UV Background

Various observational constraints are used to determine thedomain of validity of the decaying neutrino theory for the ionisation ofhydrogen in the interstellar medium of our Galaxy. The intensity of thedecay line from neutrinos near the Earth, which is being searched forby EURD, depends also on the opacity of the interstellar gassurrounding the solar system. Recent measurements of this opacity,together with our updated parameters and their own data, have been usedby the EURD team to draw conclusions about the validity of the decayingneutrino theory.