The field of the single- and double-beta decays is reviewed in the context of massive neutrinos. Direct neutrino mass measurements in the decays of ³H (KATRIN), ¹⁸⁷Re (MARE) and ¹⁶³Ho (ECHo) are discussed. A connection of the neutrinoless double-beta decay (0νββ) to neutrino oscillations is analyzed. The possibility to determine the difference between two CP Majorana phases of the neutrino mixing matrix from the study of 0νββ is investigated. The 0νββ results in ⁷⁶Ge, ¹³⁶Xe, and other nuclei are compared, and the lifetime ranges allowed or excluded at 90% C.L. are inferred. A novel mechanism of 0νββ is presented. The present-day calculations of the 0νββ nuclear matrix elements are discussed, with a particular emphasis on recent QRPA results that have achieved partial restoration of the isospin symmetry. The possibility to discriminate between different pairs of CP non-conserving mechanisms using 0νββ half-lives of different nuclei is addressed. Furthermore, the resonant neutrinoless double-electron capture in ¹⁵²Gd, ¹⁶⁴Er and ¹⁸⁰W atoms is a subject of interest.

The seminar consists of two parts:

2:30 – 3:30 pm, Part I
3:30 – 3:40 pm, Break
3:40 – 4:40 pm, Part II

Argonne Physics Division Seminar Schedule