Thu·Apr 17, 2025Thursday·April 17, 2025

1. 01*

   Charge radii of neutron-rich scandium isotopes and the seniority symmetry in the $0f_{7/2}$ shell

   S. W. Bai🇨🇳 · X. F. Yang🇨🇳 · Á. Koszorús🇧🇪 · J. C. Berengut🇦🇺 · J. Billowes🇬🇧 · M. L. Bissell🇬🇧 · K. Blaum🇩🇪 · A. Borschevsky🇳🇱 · P. Campbell🇬🇧 · B. Cheal🇬🇧 · C. S. Devlin🇬🇧 · K. T. Flanagan🇬🇧 and 21 other authors

   Nuclear charge radii of neutron-rich ${}^{47-49}$Sc isotopes were measured using collinear laser spectroscopy at CERN-ISOLDE. The new data reveal that the charge radii of scandium isotopes exhibit a distinct trend between $N=20$ and $N=28$, with ${}^{41}$Sc and ${}^{49}$Sc isotopes having similar values, mirroring the closeness of the charge radii of ${}^{40}$Ca and ${}^{48}$Ca. Theoretical models that successfully interpret the radii of calcium isotopes could not account for the observed behavior in scandium radii, in particular the reduced odd-even staggering. Remarkably, the inclusion of the new ${}^{49}$Sc radius data has unveiled a similar trend in the charge radii of $N=28$ isotones and $Z=20$ isotopes when adding the neutrons atop the ${}^{40}$Ca core and the protons atop the ${}^{48}$Ca core, respectively. We demonstrate that this trend is consistent with the prediction of the seniority model.

   nucl-exnucl-thPRL(2025)·20 citations
2. 02*

   Low-energy neutrino responses for 71Ga by electron capture rates, charge exchange reactions and shell model calculations

   Yoritaka Iwata🇯🇵 · Hiroyasu Ejiri🇯🇵 · Shahariar Sarkar🇮🇳

   Weak Gamow-Teller (GT) responses for low-lying states in ${}^{71}\mathrm{Ga}$ are crucial for studying low-energy solar neutrinos and the Ga anomaly, i.e., the possible transition to the sterile state. The responses for the ground state, the first excited state, and the second excited state are evaluated for the first time using the experimental electron capture rates, the experimental charge exchange reaction (CER) rates corrected for the tensor-interaction effect and the theoretical interacting shell model (ISM) calculations. The contributions from the two excited states to the solar and ${}^{51}\mathrm{Cr}$ neutrinos are found to be $4.2\pm 1.2\%$ of that for the ground state. This is slightly larger than the ISM values but little smaller than the CER values without corrections for the tensor interaction effect. The Ga anomaly is far beyond the uncertainty of the obtained nuclear responses.

   ↳ nucl-thhep-phnucl-exPRC(2026)·0 citations
3. 03*

   Global $\Lambda$ polarization in heavy-ion collisions at high baryon density

   Yu. B. Ivanov🇷🇺

   Based on the model of three-fluid dynamics (3FD), the global $\Lambda$ polarization ($P_{\Lambda }$) is calculated in Au+Au collisions at 3 $\le \sqrt{s_{NN}}\le$ 9 GeV, in which high baryon density is achieved. Various contributions to $P_{\Lambda }$ are considered: those from the thermal vorticity, meson field, thermal shear and spin-Hall effect. Feed-down from higher-lying resonances is also taken into account. The results are compared with available data. Special attention is payed to the collision energies of $\sqrt{s_{NN}}=$ 3, 3.2, 3.5, 3.9, and 4.5 GeV, for which a thorough scan of the energy, rapidity, and centrality dependence of $P_{\Lambda }$ is performed. The results for 3 GeV reasonably well reproduce the corresponding STAR data. While the results at $\sqrt{s_{NN}}=$ 3.2, 3.5, 3.9, and 4.5 GeV can be considered as predictions for results of measurements within the STAR fixed-target (STAR-FXT) programthat are expected in the nearest future. It is predicted that a broad maximum of $P_{\Lambda }$ is reached at $\sqrt{s_{NN}}\approx$ 3--3.9 GeV, exact position of which depends on the centrality and width of the midrapidity range of observation. Impact of the meson-field, thermal-shear and spin-Hall-effect contributions to $P_{\Lambda }$ is also studied.

   ↳ nucl-thhep-phnucl-exPRC(2025)·4 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.