A4 Article in conference proceedings
Anomalies and sterile neutrinos : Implications of new theoretical results (2019)

Kostensalo, Joel; Suhonen, Jouni (2019). Anomalies and sterile neutrinos : Implications of new theoretical results. In Civitarese, Osvaldo; Stekl, Ivan; Suhonen, Jouni (Eds.) MEDEX’19 : Workshop on Calculation of Double-Beta-Decay Matrix Elements, AIP Conference Proceedings, 2165. American Institute of Physics, 020016. DOI: 10.1063/1.5130977

JYU authors or editors

Publication details

All authors or editors: Kostensalo, Joel; Suhonen, Jouni

Parent publication: MEDEX’19 : Workshop on Calculation of Double-Beta-Decay Matrix Elements

Parent publication editors: Civitarese, Osvaldo; Stekl, Ivan; Suhonen, Jouni

Place and date of conference: Prague, Czech Republic, 27.-31.5.2019

eISBN: 978-0-7354-1910-0

Journal or series: AIP Conference Proceedings

ISSN: 0094-243X

eISSN: 1935-0465

Publication year: 2019

Number in series: 2165

Article number: 020016

Publisher: American Institute of Physics

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1063/1.5130977

Open Access: Publication channel is not openly available

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/66185

Abstract

The reactor antineutrino and the gallium anomalies have been long unexplained. Possible explanations for both of these anomalies include new physics, such as the existence of one or more eV-scale sterile neutrino. However, the previous theoretical calculations, which do not replicate the experimental results, rely on many simplifying approximations. We have performed shell model calculations in order to gain insights into these issues. In the reactor-antineutrino analysis the beta decays contributing to the cumulative electron spectrum are usually assumed to have allowed spectral shapes. However, many of these decays are actually first-forbidden. Moreover, these decays dominate the experimentally observable region. Based on the recent results, the use of this allowed approximation can at least partially explain the so called reactor antineurtino anomaly. Our new large-scale shell model calculations regarding the neutrino-nucleus scattering cross section off 71Ga decreases the gap between theory and the experimental results of GALLEX and SAGE experiments. Conflict between charge-exchange BGTs and the neutrino-nucleus cross sections can to some extent be explained by destructive interference between Gamow-Teller and tensor contributions.

Keywords: nuclear physics; particle physics; neutrinos

Fields of science: