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

Kostensalo, Joel; Suhonen, J.

doi:10.1016/j.physletb.2018.02.053

Cited by 23 publications

(38 citation statements)

References 44 publications

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“…Each shape factor was normalized to its value at E = 0. Results correspond to gA = 0.9 and MEC = 1.4, where applicable [18,54]. Note the difference in scales on the y-axis.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…The excellent agreement using the experimental data with the usual assumptions is strong evidence that our calculations are indeed accurate for the majority of the decays, especially the most important ones. Uncertainties due to g A quenching and meson exchange currents (MEC) in pseudoscalar transitions in the fission fragment region have been previously reported on [18,[53][54][55][56][57], and will be discussed in the total uncertainty estimation of Sec. V B.…”

Section: Nuclear Shell Modelmentioning

confidence: 99%

“…As such, here we vary the available parameters used in tuning shell model results to obtain agreement with experimental lifetimes. In the most general case this corresponds to a modification of the axial coupling constant, g A , whereas for the pseudoscalar transitions meson exchange currents strongly modify the so-called axial charge [54]. In order to take into account this effect, we additionally vary g A for pseudoscalar operators, which we note by MEC .…”

Section: B Uncertainty Estimationmentioning

confidence: 99%

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First-forbidden transitions in the reactor anomaly

et al. 2019

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We describe here microscopic calculations performed on the dominant forbidden transitions in reactor antineutrino spectra above 4 MeV using the nuclear shell model. By taking into account Coulomb corrections in the most complete way, we calculate the shape factor with the highest fidelity and show strong deviations from allowed approximations and previously published results. Despite small differences in the ab initio electron cumulative spectra, large differences on the order of several percents are found in the antineutrino spectra. Based on the behaviour of the numerically calculated shape factors we propose a parametrization of forbidden spectra. Using Monte Carlo techniques we derive an estimated spectral correction and uncertainty due to forbidden transitions. We establish the dominance and importance of forbidden transitions in both the reactor anomaly and spectral shoulder analysis. Based on these results, we conclude that a correct treatment of forbidden transitions is indispensable in both the normalization anomaly and spectral shoulder.

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“…Each shape factor was normalized to its value at E = 0. Results correspond to gA = 0.9 and MEC = 1.4, where applicable [18,54]. Note the difference in scales on the y-axis.…”

Section: Numerical Resultsmentioning

confidence: 99%

Section: Nuclear Shell Modelmentioning

confidence: 99%

Section: B Uncertainty Estimationmentioning

confidence: 99%

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First-forbidden transitions in the reactor anomaly

et al. 2019

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Section: The 205 Tl Reactionmentioning

confidence: 99%

“…which feeds the first excited state of 205 Pb at 2.33 keV and is of first-forbidden non-unique type [5]. Only a tiny portion of the feeding goes to the 5/2 − ground state of 205 Pb, the corresponding transition being first-forbidden unique [5,6]. According to the current Atomic Mass Evaluation [7] the Q-value is given by 50.6 ± 0.5 keV, which is so far the lowest threshold among radiochemical approaches for solar-neutrino detection.…”

Section: The 205 Tl Reactionmentioning

confidence: 99%

Calculated solar-neutrino capture rate for a radiochemical Tl205 -based solar-neutrino detector

Kostensalo

Suhonen²,

Zuber

2020

Phys. Rev. C

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Radiochemical experiments for low-energy solar-neutrino detection have been making headlines by exploiting the isotopes 37 Cl and 71 Ga. Such a very low-threshold measurement of this type can also be performed using 205 Tl, which has been considered for decades for this purpose. A unique feature of this detector nucleus is the integration is the solar-neutrino flux over millions of years owing to its long-living daughter 205 Pb. In this study we have calculated for the first time the cross section for the charged-current solar-neutrino scattering off 205 Tl. Taking into account the solar-modelpredicted neutrino fluxes and the electron-neutrino survival probabilities, a solar-neutrino capture rate of 62.2 ±8.6 SNU is determined, a value significantly smaller than in previous estimates.

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