Spectral shapes of forbidden argon beta decays as background component for rare-event searches

Abstract

The spectral shape of the electrons from the two first-forbidden unique beta- decays of Ar-39 and Ar-42 were calculated for the first time to the next-to-leading order. Especially the spectral shape of the Ar-39 decay can be used to characterise this background component for dark matter searches based on argon. Alternatively, due to the low thresholds of these experiments, the spectral shape can be investigated over a wide energy range with high statistics and thus allow a sensitive comparison with the theoretical predictions. This might lead to interesting results for the ratio of the weak vector and axial-vector constants in nuclei.

arXiv comment9 pages, 6 figures, submitted

References in corpus (6)

• First Results from the DarkSide-50 Dark Matter Experiment at Laboratori Nazionali del Gran Sasso
• The GERDA experiment for the search of 0νββ decay in ^{76}Ge
• Measurement of the specific activity of Ar-39 in natural argon
• The background in the neutrinoless double beta decay experiment GERDA
• DEAP-3600 Dark Matter Search
• On concentration of ${}^{42}$Ar in the Earth's atmosphere

Cited by in corpus (3)

• Search for dark matter with a 231-day exposure of liquid argon using DEAP-3600 at SNOLAB
• Precision Measurement of the Specific Activity of ${}^{39}$Ar in Atmospheric Argon with the DEAP-3600 Detector
• Direct Measurement of the ${}^{39}$Ar Half-life from 3.4 Years of Data with the DEAP-3600 Detector