Wed·Nov 8, 2023Wednesday·November 8, 2023

1. 01*

   First measurement of the low-energy direct capture in 20Ne(p, {\gamma})21Na and improved energy and strength of the Ecm = 368 keV resonance

   E. Masha🇩🇪 · L. Barbieri · J. Skowronski🇮🇹 · M. Aliotta🇬🇧 · C. Ananna🇮🇹 · F. Barile · D. Bemmerer🇩🇪 · A. Best🇮🇹 · A. Boeltzig🇮🇹 · C. Broggini🇮🇹 · C.G. Bruno🇬🇧 · A. Caciolli🇮🇹 and 39 other authors

   The ${}^{20}\mathrm{Ne}(\mathrm{p},\gamma {)}^{21}\mathrm{Na}$ reaction is the slowest in the NeNa cycle and directly affects the abundances of the Ne and Na isotopes in a variety of astrophysical sites. Here we report the measurement of its direct capture contribution, for the first time below $E{}_{\mathrm{cm}}=352$~keV, and of the contribution from the $E_{cm}^{}=368$~keV resonance, which dominates the reaction rate at $T=0.03-1.00$~GK. The experiment was performed deep underground at the Laboratory for Underground Nuclear Astrophysics, using a high-intensity proton beam and a windowless neon gas target. Prompt $\gamma$ rays from the reaction were detected with two high-purity germanium detectors. We obtain a resonance strength $\omega \gamma =(0.112\pm 0.002_{\mathrm{stat}}\pm 0.005_{\mathrm{sys}})$~meV, with an uncertainty a factor of $3$ smaller than previous values. Our revised reaction rate is 20\% lower than previously adopted at $T<0.1$~GK and agrees with previous estimates at temperatures $T\ge 0.1$~GK. Initial astrophysical implications are presented.

   nucl-exastro-ph.SRPRC(2023)·15 citations
2. 02*

   Observation of the distribution of nuclear magnetization in a molecule

   S. G. Wilkins🇺🇸 · S. M. Udrescu🇺🇸 · M. Athanasakis-Kaklamanakis🇨🇭 · R. F. Garcia Ruiz🇺🇸 · M. Au🇨🇭 · I. Belošević🇨🇦 · R. Berger🇩🇪 · M. L. Bissell🇬🇧 · A. A. Breier🇩🇪 · A. J. Brinson🇺🇸 · K. Chrysalidis🇨🇭 · T. E. Cocolios🇧🇪 and 24 other authors

   Rapid progress in the experimental control and interrogation of molecules, combined with developments in precise calculations of their structure, are enabling new opportunities in the investigation of nuclear and particle physics phenomena. Molecules containing heavy, octupole-deformed nuclei such as radium are of particular interest for such studies, offering an enhanced sensitivity to the properties of fundamental particles and interactions. Here, we report precision laser spectroscopy measurements and theoretical calculations of the structure of the radioactive radium monofluoride molecule, ${}^{225}$Ra${}^{19}$F. Our results allow fine details of the short-range electron-nucleus interaction to be revealed, indicating the high sensitivity of this molecule to the distribution of magnetization, currently a poorly constrained nuclear property, within the radium nucleus. These results provide a direct and stringent test of the description of the electronic wavefunction inside the nuclear volume, highlighting the suitability of these molecules to investigate subatomic phenomena.

   nucl-exphysics.atom-phphysics.chem-phphysics.comp-phScience(2025)·15 citations
3. 03*

   Estimate magnetic field strength in heavy-ion collisions via the direct photon elliptic flow

   Jing-An Sun🇨🇳 · Li Yan🇨🇳

   There must be electromagnetic fields created during high-energy heavy-ion collisions. As the quark-gluon plasma (QGP) starts to evolve hydrodynamically, although these fields may become weak comparing to the energy scales of the strong interaction, they are potentially important to some electromagnetic probes. In this work, we focus on the dissipative corrections in QGP due to the presence of a weak external magnetic field, and calculate accordingly the induced photon radiation in the framework of viscous hydrodynamics. By event-by-event hydrodynamical simulations, the experimentally measured direct photon elliptic flow can be well reproduced. Correspondingly, the direct photon elliptic flow implies a magnetic field strength around 0.1$m_{\pi }^2\sim 10^{16}$ G. This is indeed a weak field in heavy-ion physics that is compatible to the theoretical predictions, however, it is still an ultra-strong magnetic field in nature.

   ↳ nucl-thhep-phnucl-exPRC(2024)·20 citations
4. 04*

   An extended Skyrme momentum dependent potential in asymmetric nuclear matter and transport models

   Junping Yang🇨🇳 · Xiang Chen🇨🇳 · Ying Cui🇨🇳 · Yangyang Liu🇨🇳 · Zhuxia Li🇨🇳 · Yingxun Zhang🇨🇳

   Based on an extended Skyrme momentum-dependent interaction (MDI), we derive an isospin asymmetric equation of state, isospin-dependent single-particle potential and the Hamiltonian which can be used in the Boltzmann-Uehling-Uhlenbeck (BUU) model and the quantum molecular dynamics (QMD) model at the beam energy less than 1 GeV/u. As an example of the applications of extended Skyrme MDI, we also present the results obtained with the extended Skyrme momentum-dependent interaction in the improved quantum molecular dynamics model (ImQMD), and the influence of the effective mass splitting on the isospin sensitive observables, i.e., the single and double neutron-to-proton ratios, is discussed again.

   ↳ nucl-thnucl-exPRC(2024)·9 citations
5. 05*

   A multi-reflection time-of-flight mass spectrometer for the offline ion source of the PUMA experiment

   M. Schlaich🇩🇪 · J. Fischer🇩🇪 · P. Fischer🇩🇪 · C. Klink🇩🇪 · A. Obertelli🇩🇪 · A. Schmidt🇩🇪 · L. Schweikhard🇩🇪 · F. Wienholtz🇩🇪

   The antiProton Unstable Matter Annihilation experiment (PUMA) at CERN aims at investigating the nucleon composition in the matter density tail of radioactive as well as stable isotopes by use of low-energy antiproton-nucleon annihilation processes. For this purpose, antiprotons provided by the Extra Low ENergy Antiproton (ELENA) facility will be trapped together with the ions of interest. While exotic ions will be obtained by the Isotope mass Separator On-Line DEvice (ISOLDE), stable ions will be delivered from an offline ion source setup designed for this purpose. This allows the proposed technique to be applied to a variety of stable nuclei and for reference measurements. For beam purification, the ion source setup includes a multi-reflection time-of-flight mass spectrometer (MR-ToF MS). Supported by SIMION simulations, an earlier MR-ToF MS design has been modified to meet the requirements of PUMA. During commissioning of the new MR-ToF device with Ar${}^{+}$ ions, mass resolving powers in excess of 50,000 have been obtained after 150 revolutions, limited by the chopping of the continuous beam from an electron impact ionisation source.

   ↳ physics.ins-detnucl-exInt.J.Mass Spectrometry(2024)·8 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.