The neutron inelastic scattering of carbon-12, populating the Hoyle state, is a reaction of interest for the triple-alpha process. The inverse process (neutron upscattering) can enhance the Hoyle state’s decay rate to the bound states of ¹²C, effectively increasing the overall triple-alpha reaction rate. The cross section of this reaction is impossible to measure experimentally but has been determined here at astrophysically-relevant energies using detailed balance. Using a highly-collimated monoenergetic beam, here we measure neutrons incident on the Texas Active Target Time Projection Chamber (TexAT TPC) filled with CO₂ gas, we measure the 3α-particles (arising from the decay of the Hoyle state following inelastic scattering) and a cross section is extracted. Here we show the neutron-upscattering enhancement is observed to be much smaller than previously expected. The importance of the neutron-upscattering enhancement may therefore not be significant aside from in very particular astrophysical sites (e.g. neutron star mergers).

The interpretation of observations of cooling neutron star crusts in quasipersistent x-ray transients is affected by predictions of the strength of neutrino cooling via crust Urca processes. The strength of crust Urca neutrino cooling depends sensitively on the electron-capture and $\beta$-decay ground-state-to-ground-state transition strengths of neutron-rich rare isotopes. Nuclei with a mass number of $A=61$ are predicted to be among the most abundant in accreted crusts, and the last remaining experimentally undetermined ground-state-to-ground-state transition strength was the $\beta$ decay of ${}^{61}\mathrm{V}$. This Letter reports the first experimental determination of this transition strength, a ground-state branching of ${8.1}_{-3.1}^{+4.0}\%$, corresponding to a log $ft$ value of ${5.5}_{-0.2}^{+0.2}$. This result was achieved through the measurement of the $\beta$-delayed $\gamma$ rays using the total absorption spectrometer SuN and the measurement of the $\beta$-delayed neutron branch using the neutron long counter system NERO at the National Superconducting Cyclotron Laboratory at Michigan State University. This method helps to mitigate the impact of the pandemonium effect in extremely neutron-rich nuclei on experimental results. The result implies that $A=61$ nuclei do not provide the strongest cooling in accreted neutron star crusts as expected by some predictions, but that their cooling is still larger compared to most other mass numbers. Only nuclei with mass numbers 31, 33, and 55 are predicted to be cooling more strongly. However, the theoretical predictions for the transition strengths of these nuclei are not consistently accurate enough to draw conclusions on crust cooling. With the experimental approach developed in this work, all relevant transitions are within reach to be studied in the future.

Results are presented from the first neutron-transfer measurement on ${}^{80}\mathrm{Ge}$ using an exotic beam from the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. Newly measured spins and spectroscopic factors of low-lying states of ${}^{81}\mathrm{Ge}$ are determined, and the neutron capture cross section on ${}^{80}\mathrm{Ge}$ was calculated in a direct-semidirect model to provide a more realistic ($n,\gamma$) reaction rate for $r$-process simulations. Furthermore, a region of shape coexistence around $N\approx 50$ is confirmed and implications for the magic nature of ${}^{78}\mathrm{Ni}$ are discussed.

Nuclear astrophysics is an interdisciplinary research field of nuclear physics and astrophysics, seeking for the answer to a question, how to understand the evolution of the universe with the nuclear processes which we learn. We review the research activities of nuclear astrophysics in east and southeast Asia which includes astronomy, experimental and theoretical nuclear physics, and astrophysics. Several hot topics such as the Li problems, critical nuclear reactions and properties in stars, properties of dense matter, r-process nucleosynthesis, andν-process nucleosynthesis are chosen and discussed in further details. Some future Asian facilities, together with physics perspectives, are introduced.

The ¹⁵O(α,γ)¹⁹Ne reaction is an important trigger reaction leading to the rapid proton (rp) capture process in X-ray bursts. The primary uncertainty in determining its astrophysical rate is the uncertain α branching ratios of levels near E_x = 4.1 MeV in ¹⁹Ne. These states have been populated in a study of the ²⁰Ne(p, d)¹⁹Ne reaction, and α branching ratios are reported in this manuscript.