Speaker
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The $\beta$-decay strength function $S_{\beta}(\textit{E})$ governs [1-3] the nuclear energy $\textit{E}$ distribution of elementary charge-exchange excitations and their combinations like proton particle $({\pi}p)$-neutron hole $({\nu}h)$ coupled into a spin-parity $I^{\pi}$: $[{\pi}p \otimes {\nu}h]I^{\pi}$ and neutron particle $({\nu}p)$-proton hole $({\pi}h)$ coupled into a spin-parity $I^{\pi}: [{\nu}p \otimes {\pi}h]I^{\pi}$. The strength function for the Gamow–Teller ($GT$) $\beta$-transitions describes $[{\pi}p \otimes {\nu}h]1^{+}$ or $[{\nu}p \otimes {\pi}h]1^{+}$ excitations. Successful applications of the total absorption $\gamma$-spectroscopy ($TAGS$) for the $S_{\beta}(\textit{E})$ resonance structure study and methods of $TAGS$ spectra analysis were summarized in [1]. Development of the experimental technique allows application of methods of nuclear spectroscopy with high energy resolution for the $S_{\beta}(\textit{E})$ fine structure measurement [2-5]. It was demonstrated [2-6] that the high-resolution nuclear spectroscopy methods give conclusive evidence of the resonance structure of $S_{\beta}(\textit{E})$ for $GT$ and First Forbidden ($FF$) $\beta$-transitions. High-resolution nuclear spectroscopy methods [3-6] made it possible to observe the reveal splitting of the peak in the $S_{\beta}(\textit{E})$ for the $GT$ $\beta^{+}/EC$-decay of the deformed nuclei into two components. Resonance structure of the $ S_{\beta}(\textit{E}) $ for $\beta$-decay of halo nuclei was analyzed in [7-9]. It was shown that when the parent nucleus has $\textit{nn}$ Borromean halo structure, then after $GT$ $\beta^{-}$ - decay of parent state or after M1 $\gamma$-decay of Isobar Analogue Resonance ($IAR$) the states with $\textit{np}$ tango halo structure or mixed $\textit{np}$ tango + $\textit{nn}$ Borromean halo structure can be populated.
In this report the fine structure of $S_{\beta}(\textit{E})$ is analysed. Resonance structure of $S_{\beta}(\textit{E})$ for the $GT$ and $FF$ $\beta^{-}$ – decays, structure of $S_{\beta}(\textit{E})$ for halo nuclei, quenching [9] of the weak axial-vector constant ${{g_{A}}^{eff}}$, and splitting of the peaks in $S_{\beta}(\textit{E})$ for deformed nuclei connected with the anisotropy of oscillations of proton holes against neutrons (peaks in $S_{\beta}(\textit{E})$ of $GT$ $\beta^{+}/EC$–decay) or of protons against neutron holes (peaks in $S_{\beta}(\textit{E})$ of $GT$ $\beta^{-}$ – decay) are discussed.
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| The speaker is a student or young scientist | No |
|---|---|
| Section | 1. Nuclear structure: theory and experiment |
