Limit on neutrinoless double-beta decay with majoron emission in ${}_{}{}^{82}{}_{}{}^{}\mathrm{Se}$

The University of California, Irvine ${}_{}{}^{82}{}_{}{}^{}\mathrm{Se}$ double-beta-decay experiment has now accumulated 7960 h of live time. After imposition of kinematic cuts, thirteen candidate events remain in the sum-energy window between 2.0 and 3.0 MeV. If these are interpreted as neutrinoless double-beta decay with the emission of a Goldstone boson (known as the Majoron), we obtain a half-life limit of 4.4×${10}^{20}$ yr (90% confidence level). This gives, dependent upon the various calculations of the nuclear matrix elements, a limit of the majoron coupling constant ${\mathrm{g}}_{\mathrm{ee}}$≤(2–30)×${10}^{\mathrm{-}4}$. .AE