Münster 2017 – wissenschaftliches Programm
HK 61.4: Vortrag
Freitag, 31. März 2017, 14:45–15:00, F 33
Investigation of the spectral shape of the fourfold forbidden beta-decay of 113Cd with the COBRA experiment — •Arne Heimbold for the COBRA collaboration — TU Dresden, Institut für Kern und Teilchenphysik
Recently, the scientific discussion about the so-called quenching of the axial vector coupling constant gA has triggered some new calculations in nuclear physics. The possibility of a quenched coupling strength has been introduced to reproduce experimental data of double beta-decay studies with theoretical models. Of special interest are highly forbidden single beta-decays since the spectral shape of the electron momentum distribution strongly depends on the effective value of gA, but in a highly non-trivial way. The COBRA experiment at the LNGS in Italy uses CdZnTe semiconductor detectors to search for the existence of neutrinoless double beta-decay. The material acts at the same time as source of the sought double beta-decay and consists of all isotopes of Cadmium, Zinc and Tellurium according to the natural isotopic composition of those elements. One of the isotopes present is 113Cd with an abundance of about 12%. The 113Cd nucleus undergoes a fourfold forbidden, non-unique single beta-decay with a half-life of 8·1015 years, which is the most prominent signal for the COBRA demonstrator. In this talk, a first approach to compare the measured 113Cd beta spectrum of COBRA with the spectral shapes resulting from nuclear shell model calculations for various values of gA will be presented.