0619659 - ÚJF 2026 RIV PL eng C - Conference Paper (international conference)
Veselý, Petr - Denisova, Daria - Knapp, F. - Šimkovic, F.
Double-beta Decay of ⁴⁸Ca within Second Tamm-Dancoff Approximation.
Acta Physica Polonica B - Proceedings Supplement. Vol. 18. Krakow: Faculty of Physics, Astronomy and Applied Computer Science, 2025, č. článku A9. ISSN 1899-2358.
[Zakopane Conference on Nuclear Physics Extremes of the Nuclear Landscape /57./. Zakopane (PL), 25.08.2024-01.09.2024]
R&D Projects: GA ČR(CZ) GA24-10180S
Research Infrastructure: CESNET II - 90042; CERIT-SC - 90085
Institutional support: RVO:61389005
Keywords : nuclear matrix elements * nuclear properies
OECD category: Particles and field physics
DOI: https://doi.org/10.5506/APhysPolBSupp.18.2-A9

The neutrinoless double-beta decay (0νββ) nuclear matrix elements (NMEs) cannot be directly deduced from any experimental data, and their reliable calculation remains a significant challenge for the nuclear physics community. Advanced nuclear structure approaches have been developed and applied to evaluate nuclear transitions of experimental interest. However, the calculated values of 0νββ NMEs still vary widely among different methods, affecting predictions of decay rates and constraints on various lepton violation parameters. The two-neutrino double-beta (2νββ) decay, which has been experimentally confirmed for eleven isotopes, plays a crucial role in testing nuclear structure models. In this context, we present the modified formalism of the Second Tamm–Dancoff Approximation (STDA) for the calculation of double-beta decay transitions. For 2νββ of 48Ca, the corresponding NMEs are calculated within the STDA, and their dependence on relevant nuclear structure parameters is investigated. Our findings indicate that a significant quenching of the axial-vector coupling constant is necessary to accurately reproduce the half-life of 2νββ decay.
Permanent Link: https://hdl.handle.net/11104/0366289