Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays

Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays

The effects of the enhancement of the axial-charge matrix element γ5 were studied in medium heavy and heavy nuclei for first-forbidden J+↔J− decay transitions using the nuclear shell model. Noticeable dependence on the enhancement ϵMEC of the axial-charge matrix element, as well as on the value of t...

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Main Authors: Joel Kostensalo, Jouni Suhonen
Format: Article
Language:English
Published: Elsevier 2018-06-01
Series:Physics Letters B
Online Access:http://www.sciencedirect.com/science/article/pii/S0370269318301643
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spelling doaj-c68f8b9d8ce847d9a4b39cfe6c28bdb62020-11-24T23:13:11ZengElsevierPhysics Letters B0370-26932018-06-01781480484Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decaysJoel Kostensalo0Jouni Suhonen1Corresponding author.; University of Jyvaskyla, Department of Physics, P. O. Box 35, FI-40014, FinlandUniversity of Jyvaskyla, Department of Physics, P. O. Box 35, FI-40014, FinlandThe effects of the enhancement of the axial-charge matrix element γ5 were studied in medium heavy and heavy nuclei for first-forbidden J+↔J− decay transitions using the nuclear shell model. Noticeable dependence on the enhancement ϵMEC of the axial-charge matrix element, as well as on the value of the axial-vector coupling constant gA was found in the spectral shapes of 93Y, 95Sr, and 97Y. The importance of the spectrum of 138Cs in the determination of gA is discussed. Half-life analyses in the A≈95 and A≈135 regions were done, and consistent results gA≈0.90, 0.75, and 0.65, corresponding to the three enhancement scenarios ϵMEC=1.4, 1.7, and 2.0, were obtained. Connection to the reactor-antineutrino anomaly is pointed out. Keywords: Meson-exchange currents, Weak interactions, Nuclear medium effects, Forbidden beta decays, Spectral shapehttp://www.sciencedirect.com/science/article/pii/S0370269318301643
collection DOAJ
language English
format Article
sources DOAJ
author Joel Kostensalo
Jouni Suhonen
spellingShingle Joel Kostensalo
Jouni Suhonen
Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays
Physics Letters B
author_facet Joel Kostensalo
Jouni Suhonen
author_sort Joel Kostensalo
title Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays
title_short Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays
title_full Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays
title_fullStr Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays
title_full_unstemmed Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays
title_sort mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden j+↔j− decays
publisher Elsevier
series Physics Letters B
issn 0370-2693
publishDate 2018-06-01
description The effects of the enhancement of the axial-charge matrix element γ5 were studied in medium heavy and heavy nuclei for first-forbidden J+↔J− decay transitions using the nuclear shell model. Noticeable dependence on the enhancement ϵMEC of the axial-charge matrix element, as well as on the value of the axial-vector coupling constant gA was found in the spectral shapes of 93Y, 95Sr, and 97Y. The importance of the spectrum of 138Cs in the determination of gA is discussed. Half-life analyses in the A≈95 and A≈135 regions were done, and consistent results gA≈0.90, 0.75, and 0.65, corresponding to the three enhancement scenarios ϵMEC=1.4, 1.7, and 2.0, were obtained. Connection to the reactor-antineutrino anomaly is pointed out. Keywords: Meson-exchange currents, Weak interactions, Nuclear medium effects, Forbidden beta decays, Spectral shape
url http://www.sciencedirect.com/science/article/pii/S0370269318301643
work_keys_str_mv AT joelkostensalo mesonicenhancementoftheweakaxialchargeanditseffectonthehalflivesandspectralshapesoffirstforbiddenjjdecays
AT jounisuhonen mesonicenhancementoftheweakaxialchargeanditseffectonthehalflivesandspectralshapesoffirstforbiddenjjdecays
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