Electron-capture branch of Tc100 and tests of nuclear wave functions for double-β decays

We present a measurement of the electron-capture branch of Tc100. Our value, B(EC)=(2.6±0.4)×10-5, implies that the Mo100 neutrino absorption cross section to the ground state of Tc100 is roughly 50% larger than previously thought. Disagreement between the experimental value and QRPA calculations relevant to double-β decay matrix elements persists. We find agreement with previous measurements of the 539.5- and 590.8-keV γ-ray intensities. © 2008 The American Physical Society.