EFFECTS FROM CHANGES IN THE FINAL-STATE SPECTRUM ON THE NEUTRINO MASSDETERMINATION FROM T-2 BETA-DECAY EXPERIMENTS

Some improvements in the final state spectrum of T-2 beta decay are di scussed. Their importance for neutrino mass determination has been est imated through numerical experiments. Results depend most strongly on the length of the energy interval of the experimental spectrum used in the fit to the theoretical spectrum. For a Gaussian resolution functi on and fit intervals to 1.1 keV below the end point energy physically plausible changes in the final state distribution could contribute as much as -30 eV(2) to the systematic error in m(nu)(2). A wider resolut ion function can increase this error by a factor of 2 or 3. An improve d final state spectrum for neutrino mass determination is presented.