Confirmation of gA quenching using the revised spectrum-shape method for the analysis of the 113Cd β-decay as measured with the COBRA demonstrator
Kostensalo, J., Suhonen, J., Volkmer, J., Zatschler, S., & Zuber, K. (2021). Confirmation of gA quenching using the revised spectrum-shape method for the analysis of the 113Cd β-decay as measured with the COBRA demonstrator. Physics Letters B, 822, Article 136652. https://doi.org/10.1016/j.physletb.2021.136652
Published inPhysics Letters B
© 2021 The Authors. Published by Elsevier B.V.
In this article we present an updated spectrum-shape analysis of the113Cd fourfold forbidden non-uniqueβ-decay transition in order to address the quenching of the weak axial-vector coupling gA in low-momentum exchange nuclear processes. The experimental data were collected in a dedicated low-threshold run with the COBRA demonstrator at the LNGS and resulted in 44 individual113Cdspectra. These data are evaluated in the context of three nuclear model frameworks based on a revised version of the spectrum-shape method and the conserved vector current hypothesis. The novel idea devised in the present work is to fit the value of the small relativistic nuclear matrix element (s-NME) driving the nuclear model calculations, which remained essentially as a free parameter in previous studies. This is done by tuning the nuclear structure calculations and making use of the interplay of gA and the s-NME such that the experimentally known113Cd half-life gets reproducible by the different frameworks. In this way, a best fit s-NME value can be derived for each of the considered nuclear models, which finally enters the template calculations used to perform the spectrum-shape analysis for each of the obtained113Cd spectra. The primary analysis strategy results in significantly quenched values of the axial-vector coupling for all three nuclear models: gA(ISM)=0.907±0.064,gA(MQPM)=0.993±0.063andgA(IBFM-2)=0.828±0.140. Moreover, with our data-driven approach one of the main shortcomings of the spectrum-shape method has been resolved. This achievement is a milestone in the description of strongly forbiddenβ-decays and adds to the indications for the existence of a quenching of gA in low-momentum exchange nuclear processes. ...
Publication in research information system
MetadataShow full item record
Related funder(s)Research Council of Finland
Funding program(s)Academy Project, AoF
Additional information about fundingthe collaboration would like tothank the German Research Foundation (Deutsche Forschungs-gemeinschaft, DFG) for its past funding and the support of theCOBRA XDEM upgrade under the project numbers ZU123/3and GO1133/1. Additionally, the support by the Academy of Finland under the project number 318043 and from the Jennyand Antti Wihuri Foundation is acknowledged.
Showing items with similar title or keywords.
COBRA collaboration (Elsevier, 2020)A dedicated study of the quenching of the weak axial-vector coupling strength gA in nuclear processes has been performed by the COBRA collaboration. This investigation is driven by nuclear model calculations which show ...
Haaranen, Mikko; Kotila, Jenni-Mari; Suhonen, Jouni (American Physical Society, 2017)Effective values of the axial-vector coupling constant gA have lately attracted much attention due to the prominent role of gA in determining the half-lives of double β decays, in particular their neutrinoless mode. The ...
Haaranen, Mikko (University of Jyväskylä, 2017)This is a thesis consisting of seven publications and an introductory part on theoretical studies on rare single beta decays. Firstly, the theoretical framework is applied to the computation of partial half-lives for ...
Kostensalo, Joel; Lisi, Eligio; Marrone, Antonio; Suhonen, Jouni (American Physical Society (APS), 2023)We present an alternative analysis of the 113Cdβ-decay electron energy spectrum in terms of spectral moments μn, corresponding to the averaged values of nth powers of the β particle energy. The zeroth moment μ0 is related ...
Suhonen, Jouni (Jagellonian University, 2018)The quenching of the weak axial-vector coupling strength, gA, in nuclear β decays is reviewed. The quenching is discussed for both the Gamow–Teller decays and the forbidden β decays of different variants. Both the historical ...