Mon·May 27, 2024Monday·May 27, 2024

1. 01*

   Modeling of Deuteron Induced Reactions on Molybdenum at Low Energies

   M. Avrigeanu🇷🇴 · E. Šimečková · J. Mrázek🇨🇿 · C. Costache🇷🇴 · V. Avrigeanu🇷🇴

   The activities of the EUROfusion consortium on the development of high quality nuclear data for fusion applications include evaluations of deuteron induced reactions and related data libraries for needs of the DEMO fusion power plant and IFMIF-DONES neutron--source nuclear analyses. Molybdenum is one of the major constituents of the reference stainless steels used in critical components of these projects. While the TENDL deuteron data library was the current reference used by EUROfusion, need of its further improvement has already been pointed out. The weak binding energy of the deuteron is responsible for the high complexity of its interaction with nuclei, involving also a variety of reactions initiated by the nucleons following the deuteron breakup. Their analysis completed that of the deuteron interactions with Mo and its stable isotopes, from elastic scattering to pre-equilibrium and compound--nucleus reactions, up to 50 MeV. A particular attention has been paid to the breakup, stripping, and pick-up direct interactions which amount to around half of the deuteron total--reaction cross section. The due account of most experimental data has validated the present approach, highlighted some prevalent features, and emphasized weak points and consequently the need for modeling/evaluation upgrade.

   nucl-exnucl-thJ.Fusion Energ.(2024)·3 citations
2. 02*

   Measurement of $\gamma$-rays generated by neutron interaction with ${}^{16}$O at 30 MeV and 250 MeV

   T. Tano🇯🇵 · T. Horai🇯🇵 · Y. Ashida🇺🇸 · Y. Hino🇯🇵 · F. Iacob🇮🇹 · A. Maurel🇫🇷 · M. Mori🇯🇵 · G. Collazuol🇮🇹 · A. Konaka🇨🇦 · Y. Koshio🇯🇵 · T. Nakaya🇯🇵 · T. Shima🇯🇵 · R. Wendell🇯🇵

   Deep understanding of $\gamma$-ray production from the fast neutron reaction in water is crucial for various physics studies at large-scale water Cherenkov detectors. We performed test experiments using quasi-mono energetic neutron beams ($E_n=30$ and 250~MeV) at Osaka University's Research Center for Nuclear Physics to measure $\gamma$-rays originating from the neutron-oxygen reaction with a high-purity germanium detector. Multiple $\gamma$-ray peaks which are expected to be from excited nuclei after the neutron-oxygen reaction were successfully observed. We measured the neutron beam flux by using a liquid scintillator for the cross section measurement. With a spectral fitting analysis based on the tailored $\gamma$-ray signal and background templates, we measured cross sections for each observed $\gamma$-ray component. The results will be useful to validate neutron models employed in the on-going and future water Cherenkov experiments.

   nucl-exhep-exPTEP(2024)·8 citations
3. 03*

   High-resolution spectroscopy of neutron-rich Br isotopes and signatures for a prolate-to-oblate shape transition at N=56

   J. Dudouet🇫🇷 · G. Colombi🇫🇷 · D. Reygadas Tello🇫🇷 · C. Michelagnoli🇫🇷 · D.D. Dao🇫🇷 · F. Nowacki🇫🇷 · M. Abushawish🇫🇷 · E. Clément🇫🇷 · C. Costache🇷🇴 · G. Duchêne🇫🇷 · F. Kandzia🇫🇷 · A. Lemasson🇫🇷 and 30 other authors

   The first systematic experimental study of the neutron-rich Br isotopes with two complementary state-of-the-art techniques is presented. These isotopes have been populated in the fission process at two different facilities, GANIL and ILL. New spectroscopic information has been obtained for odd-even ${}^{87-93}$Br isotopes and the experimental results have been compared with state-of-the-art Large-Scale Shell-Model and DNO Shell-Model calculations. As a result of such theoretical approaches, a transition from prolate (${}^{87,89}$Br) to oblate (${}^{91,93}$Br) shapes is obtained from the subtle balance between proton and neutron quadrupole deformations, as a clear signature of pseudo-SU3 quadrupole regime.

   nucl-exnucl-thPRC(2024)·4 citations
4. 04*

   Principal components of nuclear mass models

   X. H. Wu🇨🇳 · P. W. Zhao🇨🇳

   The principal component analysis approach is employed to extract the principal components contained in nuclear mass models for the first time. The effects coming from different nuclear mass models are reintegrated and reorganized in the extracted principal components. These extracted principal components are recombined to build new mass models, which achieve better accuracy than the original theoretical mass models. This indicates that the effects contained in different mass models can work together to improve the nuclear mass predictions with the help of the principal component analysis approach.

   ↳ nucl-thnucl-exSCPMA(2024)·15 citations
5. 05*

   $K^{-}d\to \pi \Lambda N$ reaction with in-flight kaons for studying the $\Lambda N$ interaction

   Shunsuke Yasunaga🇯🇵 · Daisuke Jido🇯🇵 · Takatsugu Ishikawa🇯🇵

   The $\Lambda N$ invariant mass spectra for the reactions $K^{-}d\to {\pi }^{-}\Lambda p$ and $K^{-}d\to {\pi }^0\Lambda n$ are calculated for experimental study of isospin symmetry breaking in the $\Lambda N$ scattering at low energies, the difference in the scattering lengths and effective ranges of $\Lambda p$ and $\Lambda n$ systems. The calculations are performed for in-flight kaons with a momentum of 1000 MeV/c with employing partial wave analysis up to the p-wave for meson-baryon amplitudes and the spin-flip term for baryon-baryon amplitudes. Kinematic selection is utilized to suppress the background processes by selecting forward-emitting pions and higher momentum nucleons. It is worth noting that isospin symmetry breaking in the $\Lambda N$ system can be extracted from the difference of the $\Lambda N$ invariant mass spectra between the $K^{-}d\to {\pi }^{-}\Lambda p$ and $K^{-}d\to {\pi }^0\Lambda n$ reactions.

   ↳ nucl-thhep-phnucl-exPRC(2025)·2 citations
6. 06*

   Constraints for rare electron-capture decays mimicking detection of dark-matter particles in nuclear transitions

   Aagrah Agnihotri🇫🇮 · Jouni Suhonen🇫🇮 · Hong Joo Kim🇰🇷

   We give for the first time, theoretical estimates of unknown rare electron-capture (EC) decay branchings of ${}^{44}$Ti, ${}^{57}$Co, and ${}^{139}$Ce, relevant for searches of (exotic) dark-matter particles. The nuclear-structure calculations have been done exploiting the nuclear shell model (NSM) with well-established Hamiltonians and an advanced theory of $\beta$ decay. In the absence of experimental measurements of these rare branches, these estimates are of utmost importance for terrestrial searches of dark-matter particles, such as axionic dark matter in the form of axion-like particles (ALPs), anapole dark matter, and dark photons in nuclear transitions. Predictions are made for EC-decay rates of 2${}^{nd}$-forbidden unique (FU) and 2${}^{nd}$-forbidden non-unique (FNU) EC transitions that can potentially mimic dark-matter-particle detection in dedicated underground experiments designed to observe the absence of the corresponding nuclear electromagnetic transitions.

   ↳ nucl-thhep-exhep-phnucl-exPRL(2024)·2 citations

* 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.