Speaker
Description
The information on how the nuclear structure effects the beta-decay or charge-exchange reactions is most conveniently expressed by a strength function. The beta-decay probability is proportional to the product of the lepton part described by the Fermi function and the nucleon part described by beta-decay strength function. Beta-decay strength function reflects the distribution of the squared beta-decay matrix elements with respect to the excitation energy of the nuclear states of the daughter nucleus [1,2].
In the case of precise Wigner’s SU(4)symmetry Isobar Analog Resonance (IAR) and Gamow-Teller Resonance(GTR) energies are degenerate and we may expect that E(IAR) = E(GTR). From our estimation follows [3] that the value Z/N = 0.6 corresponds to the SU(4) region. The quenching of g(A) can be observed in GT beta-decay of halo nuclei and of some neutron rich nuclei, where E(GTR) < E(IAR) [4] and GTR (or low-energy super Gamow-Teller phonon [5]) may be observed. Method of g(A) determination by comparison of experimental value of total beta-decay strength for GT beta-transitions with the Ikeda sum rule is the model-independent method and it may be applied for some halo nuclei and neutron rich nuclei [4].
Possible experiments on beta-decay strength function study in halo and in neutron rich nuclei are discussed.
[1] Yu.V. Naumov, A.A. Bykov, I.N. Izosimov, Sov. J. Part. Nucl. 14, 175 (1983)
[2] I.N. Izosimov, V.G. Kalinnikov, A.A. Solnyshkin, Phys. of Part. and Nucl. 42, 963 (2011)
[3] I.N. Izosimov, Physics of Particles and Nuclei Lett. 15, 621 (2018)
[4] I.N. Izosimov, Joint Institute for Nuclear Research Preprint E6-2018-64, Dubna, 2018.
[5] Y. Fujita et al, Phys. Rev. C 91, 064316 (2015)
