Phase-space factors for double-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>decay

Abstract

A complete and improved calculation of phase-space factors for $2\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ and $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ decay is presented. The calculation makes use of exact Dirac wave functions with finite nuclear size and electron screening and includes lifetimes, single and summed electron spectra, and angular electron correlations.