10 Search Results

Here, evaluated 2β^–(2ν) half-lives and their systematics were reexamined in the framework of a phenomenological approach. Decay rate dependence on nuclear deformation, decay energy, shape coexistence, and forbidden transitions was observed. The following analysis showed distinct impacts of decay energy on half lives, and deformation parameters on effective nuclear matrix elements. These findings were used to predict T_1/2 for 36 isotopes of interest. Present work results were compared with published data.

In our publication [Nucl. Phys. A 1027 (2022) 122511, https://doi.org/10.1016/j.nuclphysa.2022.122511] we have detected typographical errors in Table 4 [List of $$2^+_1$$ States in Even-Even Nuclei]. The misprints of decimals with one or more trailing zeros are not central to our findings, however, they may confuse the journal readers and require corrections. In addition, we have included recent results for the $$0^+_2$$ and $$2^+_1$$ first excited states that are not available in the ENSDF library as of April, 2021 or B(E2) tables.

Here, the spin and parity (J^π) assignments in even-even nuclei were reviewed across the nuclear chart using the Evaluated Nuclear Structure Data File (ENSDF). The prevalence of 2$$+\atop{1}$$ first or lowest excited states is confirmed. The properties of 0$$+\atop{2}$$, 1$$-\atop{1}$$, and 3$$-\atop{1}$$ lowest excited states were reexamined using the ENSDF data evaluation procedures. The J^π systematic trends and correlations between level quantum numbers and nuclear physics phenomena are discussed.

The recent observation of neutron stars merger by the LIGO collaboration and the measurements of the event’s electromagnetic spectrum as a function of time for different wavelengths, have altered profoundly our understanding of the r-process site, as well as considerably energized nuclear astrophysics research efforts. R-process abundances are a key element in r-process simulations, as a successful calculation must account for these abundances in the final debris of a stellar cataclysmic event. In this letter, mankind’s complete knowledge of neutron cross sections obtained in the last80 years, as encapsulated in the latest release of the Evaluated Nuclear Data File (ENDF/B)more » library, is used to obtain solar r-process abundances in a novel way. Here, ENDF/B cross sections has been successfully used for decades in nuclear power and defense applications and are now used to obtain r-process abundances in a fully traceable, documented and unbiased way.« less

The rapid progress of atomic and nuclear physics in the twentieth century altered the way scientific results are documented, preserved and disseminated. Boris Pritychenko discusses how atomic and nuclear data tables have become a central resource for the community.

Using Grodzins formalism, we analyze systematics of our latest evaluated B(E2) data for all the even–even nuclei in Z=2–104. The analysis indicates a low predictive power of systematics for a large number of cases, and a strong correlation between B(E2) fit values and nuclear structure effects. These findings provide a strong rationale for introduction of individual or elemental (grouped by Z) fit parameters. The current estimates of quadrupole collectivities for systematics of even–even nuclei yield complementary values for comparison with experimental results and theoretical calculations. Furthermore, the lists of fit parameters and predicted B(E2) values are given and possible implicationsmore » are discussed.« less

Evolution of low-energy nuclear physics publications over the last 120 years has been analyzed using nuclear physics databases. An extensive study of Nuclear Science References, Experimental Nuclear Reaction Data (EXFOR), and Evaluated Nuclear Structure Data File (ENSDF) contents provides a unique picture of refereed and non-refereed nuclear physics references. Significant fractional contributions of non-refereed reports, private communications and conference proceedings in EXFOR and ENSDF databases in the 1970’s reflect extensive experimental campaigns and an insufficient number of research journals. This trend has been reversed in recent years because the number of measurements is much lower, while number of journals ismore » higher. In addition, nuclear physics results are mainly published in a limited number of journals, such as Physical Review C and Nuclear Physics A. In the present work, historic publication trends and averages have been extracted and analyzed using nuclear data mining techniques. Lastly, the results of this study and implications are discussed and conclusions presented.« less

In this paper, we establish the equivalence of the various techniques for measuring B(E2) values using a statistical analysis. Data used in this work come from the recent compilation by B. Pritychenko et al. (2016). We consider only those nuclei for which the B(E2) values were measured by at least two different methods, with each method being independently performed at least twice. Our results indicate that most prevalent methods of measuring B(E2) values are equivalent, with some weak evidence that Doppler-shift attenuation method (DSAM) measurements may differ from Coulomb excitation (CE) and nuclear resonance fluorescence (NRF) measurements. However, such anmore » evidence appears to arise from discrepant DSAM measurements of the lifetimes for ⁶⁰Ni and some Sn nuclei rather than a systematic deviation in the method itself.« less

Experimental results of E2 transition probabilities or B(E2) values for the known first 2⁺ states in 447 even–even nuclei have been compiled and evaluated. The evaluation policies for the analysis of experimental data have been described and new results are discussed. The recommended B(E2) values have been compared with comprehensive shell model calculations for a selected set of nuclei, where such theoretical procedures are amenable. The present work was motivated by a rapid increase in the number of new B(E2) measurements for the first 2⁺ states since the previous evaluation of such data by S. Raman et al. published inmore » 2001. Finally, future plans to investigate the systematics of B(E2)↑ values, and intercomparison of different experimental techniques to obtain these data are outlined.« less