Speaker
Description
Astro-$\nu$ interactions are studied by inverse $\beta$ decays and $\nu$-properties beynod the standard model are studied by neutrinoless double beta decays (0$\nu\beta\beta$). The $\beta$ and $\beta\beta$ nuclear matrix elements (NMES) consist mainly of the axial-vector spin ($\sigma$) isospin($\tau$) components, The delta-isobar ($\Delta$) resonance excited by the quark $\tau\sigma$ excitation of nucleon in the nucleus is shown to quench the axial-vector components of NMEs. The effects are evaluated by using experimental energies and the strengths of the Gamow-Teller (nuclear $\tau\sigma$) resonsnces. The quenching effect is incorpolated by the effective axial-vector coupling around $g_A^{eff}$ $\approx$0.7$\pm$0.1 in units of $g_A$ for a free nucleon. Impact of the $\Delta$ resonsnce on neutrino studues in nuclei is discussed.
H. Ejiri et al., Phys. Rep. 797, 1 2019, Phys. Rev. C105, L022501, C108, L11302 2023.
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| Are you a student or postdoc? | no |
