A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Analysis of the total β-electron spectrum of 92Rb : Implications for the reactor flux anomalies (2022)

Ramalho, M., Suhonen, J., Kostensalo, J., Alcalá, G. A., Algora, A., Fallot, M., Porta, A., & Zakari-Issoufou, A.-A. (2022). Analysis of the total β-electron spectrum of 92Rb : Implications for the reactor flux anomalies. Physical Review C, 106(2), Article 024315. https://doi.org/10.1103/PhysRevC.106.024315

JYU-tekijät tai -toimittajat

De Oliveira Ramalho, Marlom
Suhonen, Jouni

Julkaisun tiedot

Julkaisun kaikki tekijät tai toimittajat: Ramalho, M.; Suhonen, J.; Kostensalo, J.; Alcalá, G. A.; Algora, A.; Fallot, M.; Porta, A.; Zakari-Issoufou, A.-A.

Lehti tai sarja: Physical Review C

ISSN: 2469-9985

eISSN: 2469-9993

Julkaisuvuosi: 2022

Ilmestymispäivä: 16.08.2022

Volyymi: 106

Lehden numero: 2

Artikkelinumero: 024315

Kustantaja: American Physical Society (APS)

Julkaisumaa: Yhdysvallat (USA)

Julkaisun kieli: englanti

DOI: https://doi.org/10.1103/PhysRevC.106.024315

Julkaisun avoin saatavuus: Ei avoin

Julkaisukanavan avoin saatavuus: 

Julkaisu on rinnakkaistallennettu (JYX): https://jyx.jyu.fi/handle/123456789/83703

Tiivistelmä

We present here a microscopic nuclear-structure calculation of a β-electron spectrum including all the β-decay branches of a high Q-value reactor fission product contributing significantly to the reactor antineutrino energy spectrum. We perform large-scale nuclear shell-model calculations of the total electron spectrum for the β− decay of 92Rb to states in 92Sr using a computer cluster. We exploit the β-branching data of a recent total absorption γ-ray spectroscopy (TAGS) measurement to determine the effective values of the weak axial-vector coupling, gA, and the weak axial charge, gA(γ5). By using the TAGS data we avoid the bias stemming from the pandemonium effect which is a systematic error biasing the usual β-decay measurements. We take fully into account all the involved allowed and forbidden β transitions, in particular the first-forbidden nonunique ones which have earlier been shown to be relevant in the context of the reactor-antineutrino flux anomaly and the unexplained spectral shoulder, the “bump,” the former one having been interpreted as one of the strongest evidence for the existence of sterile neutrinos. Here we are able to present quantitative evidence for the relevance of forbidden nonunique β− decays in a total β spectrum of a fission product, in this case 92Rb, which is one of the major contributors to the total reactor antineutrino spectral shape. We demonstrate that taking the forbidden spectral shapes fully into consideration leads for 92Rb to a 2.6%–4.6% reduction in the expected inverse β-decay rate at the reactor antineutrino telescopes. We also confirm by our calculation of a total β-electron spectrum that the forbidden transitions can contribute to the formation of the spectral bump in the reactor-antineutrino flux profile.

YSO-asiasanat: ydinfysiikka; rubidium; beetasäteily; neutriinot

Liittyvät organisaatiot

Hankkeet, joissa julkaisu on tehty

OKM-raportointi: Kyllä

Raportointivuosi: 2022

JUFO-taso: 2