Search for a heavy neutrino in the β-decay of 35S

Recent experimental evidence suggests that the neutrino (strictly, an antineutrino) emitted in the β-decay of tritium is a mixture of two mass eigen states |ν1> and |ν2> where |νsub(e)>=cos theta|ν1>+sin theta|ν2> with msub(ν1) < 50 eV and msub(ν2)=17.1+-0.2 keV and sin2 theta=0.03. Such an observation, if confirmed, will have far-reaching consequences in cosmology and particle physics. In the experiment reported here, a search was made for such an admixture in the β-decay of 35S. The authors fail to confirm the presence of mixing of neutrinos with mass 17.1 keV and place an upper limit on such an admixture of 0.6% (90% confidence level). (author)