Wed·Mar 26, 2025Wednesday·March 26, 2025

1. 01*

   Comprehensive Review of 2$\beta$ Decay Half-Lives

   B. Pritychenko🇺🇸 · V.I. Tretyak🇺🇦

   The double-beta (2$\beta$)-decay is the rarest nuclear physics process, and its experimental half-lives (T${}_{1/2}$) exceed the age of the Universe from nine to fourteen orders of magnitude. Double-beta decay was observed, and its half-life was measured in 14 parent nuclei using direct, radiochemical, and geochemical methods. The decay observables are analyzed using the Evaluated Nuclear Structure Data File (ENSDF) procedures, and the recommended T${}_{1/2}$ were deduced. Using the calculated values of phase factors, the effective nuclear matrix elements were extracted and compared with available data. Thousands of theoretical and experimental works have been dedicated to these topics in the last 85 years, and we present two data sets of recommended values to encapsulate the results.

   nucl-exnucl-thAtom.Data Nucl.Data Tabl.(2025)·15 citations
2. 02*

   Atomic determination of the nuclear quadrupole moment $\mathrm{Q}{(}^{209}\mathrm{Bi})$ using the multi-configuration Dirac-Hartree-Fock method

   Jiguang Li · Jacek Bieroń🇵🇱 · Michel Godefroid🇧🇪 · Per Jönsson

   The multiconfiguration Dirac-Hartree-Fock method implemented in the Grasp2018 package was employed to calculate the magnetic dipole hyperfine interaction constants and electric field gradients of levels in the ground configuration of the neutral bismuth atom. Combining the calculated electric field gradient of the ground state with the measured electric quadrupole hyperfine interaction constant, we extracted the nuclear quadrupole moment for the ${}^{209}$Bi isotope, $\mathrm{Q}{(}^{209}\text{Bi})=-422(22)$~mb. This value, together with other results obtained from atomic- and molecular-structure calculations, created the ``world average" nuclear quadrupole moment of this isotope, $\mathrm{Q}{(}^{209}\text{Bi})=-420(17)$~mb.

   ↳ physics.atom-phnucl-exnucl-thEur.Phys.J.D(2025)·0 citations
3. 03*

   Measurement of $\beta$-particles to determine cross sections relevant to the weak r-process

   Sándor R. Kovács · Tibor Norbert Szegedi · Ákos Tóth · Attila Németh · Manoj Kumar Pal · Edit Szilágyi · Mihály Braun🇷🇺 · György Gyürky · Zoltán Elekes🇭🇺 · Zoltán Halász · Tamás Szücs🇭🇺 · Gábor Gyula Kiss🇭🇺

   The neutron-rich isotopes with 30 $\le$ Z $\le$ 45 are thought to be synthesised in neutrino-driven winds after the collapse of a massive star. This nucleosynthesis scenario, called the weak r-process, is studied using nuclear reaction network calculations. The accuracy of the nucleosynthesis simulations is strongly influenced by the reliability of the nuclear physics input parameters used. Recently, it has been demonstrated that ($\alpha$,n) reactions play a particularly important role in the weak r-process, but their rates -- computed from the cross sections -- are only known with large uncertainties in the astrophysically relevant temperature range. The half-lives of the products of some key reactions are such that, in principle, the cross sections can be studied using the activation technique. In many cases, however, the $\beta$-decay of the reaction products leads to the ground state of the daughter nucleus, hence no gamma emission occurs. The purpose of this manuscript is to present our setup with which we determine the cross sections by measuring the yield of $\beta$-particles emitted during radioactive decay. The ${}^{86}$Kr($\alpha$,n)${}^{89}$Sr reaction cross-section measurement is used, as a case study.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2025)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.