The quenching of the axial-vector coupling constant $g_A$ in $β$-decay: joint effects from chiral two-body currents and many-body correlations
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| Main Authors: | , , , , , , |
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| Format: | Preprint |
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2026
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| _version_ | 1866916031755190272 |
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| author | Wang, Bin-Lei Lv, Wan-Li Cao, Li-Gang Niu, Yi-Fei Colo, Gianluca Sagawa, Hiroyuki Zhang, Feng-Shou |
| author_facet | Wang, Bin-Lei Lv, Wan-Li Cao, Li-Gang Niu, Yi-Fei Colo, Gianluca Sagawa, Hiroyuki Zhang, Feng-Shou |
| contents | In nuclear $β$-decay calculations, the axial-vector coupling constant $g_A \approx 1.27$ usually needs to be quenched phenomenologically by a factor $q~\approx$ 0.75 to reproduce {the Gamow-Teller (GT) transition strengths}. We propose a novel approach to quench the GT {strength} of $β$-decay within the microscopic random phase approximation (RPA) plus particle-vibration coupling (PVC) approach, incorporating the contributions of two-body currents (TBC) derived from chiral effective field theory ($χ$EFT). Self-consistent RPA+PVC calculations are performed in three doubly magic nuclei, $^{56}$Ni, $^{100}$Sn, and $^{132}$Sn, with various Skyrme energy density functionals, and the effect of TBC is evaluated by using the obtained many-body wavefunctions. A combined effects of the many-body correlations introduced by PVC and chiral TBC quench the GT strength and reproduce quantitatively experimental data without any additional adjustments. The extracted quenching factors $q$ by the present microscopic model lie in the range $\approx$ 0.73--0.80, which is quite close to the commonly adopted empirical value of $q \approx 0.75$. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2605_21218 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | The quenching of the axial-vector coupling constant $g_A$ in $β$-decay: joint effects from chiral two-body currents and many-body correlations Wang, Bin-Lei Lv, Wan-Li Cao, Li-Gang Niu, Yi-Fei Colo, Gianluca Sagawa, Hiroyuki Zhang, Feng-Shou Nuclear Theory In nuclear $β$-decay calculations, the axial-vector coupling constant $g_A \approx 1.27$ usually needs to be quenched phenomenologically by a factor $q~\approx$ 0.75 to reproduce {the Gamow-Teller (GT) transition strengths}. We propose a novel approach to quench the GT {strength} of $β$-decay within the microscopic random phase approximation (RPA) plus particle-vibration coupling (PVC) approach, incorporating the contributions of two-body currents (TBC) derived from chiral effective field theory ($χ$EFT). Self-consistent RPA+PVC calculations are performed in three doubly magic nuclei, $^{56}$Ni, $^{100}$Sn, and $^{132}$Sn, with various Skyrme energy density functionals, and the effect of TBC is evaluated by using the obtained many-body wavefunctions. A combined effects of the many-body correlations introduced by PVC and chiral TBC quench the GT strength and reproduce quantitatively experimental data without any additional adjustments. The extracted quenching factors $q$ by the present microscopic model lie in the range $\approx$ 0.73--0.80, which is quite close to the commonly adopted empirical value of $q \approx 0.75$. |
| title | The quenching of the axial-vector coupling constant $g_A$ in $β$-decay: joint effects from chiral two-body currents and many-body correlations |
| topic | Nuclear Theory |
| url | https://arxiv.org/abs/2605.21218 |