Phase space factors for ${\beta }^{+}{\beta }^{+}$ decay and competing modes of double-$\beta$ decay

Abstract

A complete and improved calculation of phase space factors (PSF) for $2\nu {\beta }^{+}{\beta }^{+}$ and $0\nu {\beta }^{+}{\beta }^{+}$ decay, as well as for the competing modes $2\nu EC{\beta }^{+}$, $0\nu EC{\beta }^{+}$, and $2\nu ECEC$, is presented. The calculation makes use of exact Dirac wave functions with finite nuclear size and electron screening and includes life-times, single and summed positron spectra, and angular positron correlations.

Comments: 13 pages, 14 figures. arXiv admin note: text overlap with arXiv:1209.5722