Physical Review C

High-precision measurements of nuclear decay energies can reveal rare low-Q transitions with enhanced sensitivity to the absolute neutrino mass. Using the JYFLTRAP double Penning trap and the PI-ICR technique, the electron-capture Q value of ${}^{113}$Sn was determined with an eightfold improvement in precision over the previous evaluation. Combining the new mass result with known excited states in ${}^{113}$In identifies two energetically allowed low-Q electron-capture branches. In particular, an allowed transition to the 1029.650-keV state has $Q{*}_{EC}=9.60(20)$ keV and lies close to the L-shell binding energies. Atomic and nuclear calculations show enhanced spectral sensitivity near the endpoint, making this decay an interesting complementary system for future direct neutrino-mass studies.

Photons and dileptons produced in high energy nuclear collisions contain undistorted information about the conditions at their point of emission, such as the local temperature, flow velocity, and chemical potential. Using state of the art modeling of the collision dynamics, which reproduce hadronic spectra, the authors find good agreement with measurements by the STAR Collaboration at the Relativistic Heavy Collider, but differ from measurements by the PHENIX Collaboration in terms of magnitude but not shape. This work shows that the multimessenger approach to heavy-ion collisions previously used at higher energy is amenable to baryon-rich environments at lower temperatures, and paves the way for more comprehensive studies of the QCD phase diagram.

We have demonstrated a new way to reveal the electrical ‘fingerprint’ left by a single nuclear decay. When a radioactive atom implanted just beneath a surface decays, its products can eject a shower of secondary electrons from the surrounding material. Often undetected by conventional laboratory instruments, these electrons can create a substantial background in experiments that rely on precise electron counting. To study this process, we use a microscopic glass sphere suspended by laser light as a highly isolated charge detector with sub-electron charge sensitivity. We pair the sphere with a conventional scintillation detector that records the emitted radiation. By matching the timing of the two signals, we can link each charge change to a specific decay. We found that one alpha decay can knock more than 100 electrons from a material’s surface, while beta decays release far fewer. Measuring these electrical fingerprints one decay at a time could help experiments searching for rare events, including future sterile neutrino searches, to distinguish genuine signals from electrons released by radioactive impurities near detector surfaces.

An enhanced Full-Potential Linear Augmented Plane Wave (FLAPW) method is introduced which incorporates the small Dirac components of valence states—specifically the 6p1/2 semicore states—in actinide solids such as Ac, Th, ThO${}_2$, and UO${}_2$. By accounting for these small components, it is demonstrated that the valence electron density at the nucleus increases by a factor of 2.4 to 4.3, correcting standard approximations in computational physics that omit significant valence electron density near the atomic nucleus. These refined relativistic Dirac calculations offer improved theoretical precision for nuclear phenomena such as internal conversion, Mossbauer spectroscopy, and electron bridge effects, providing foundational electronic structure insights relevant to technologies like ${}^{229}$Th-based solid-state nuclear clocks.

Nuclear effective field theories (EFTs) have had enormous impact on ab initio nuclear physics, yet many open questions remain regarding their development and application. This work studies Chiral EFT in a strictly RG-invariant formulation and applies it to the process of deuteron electrodisintegration, extending the reach of such calculations from static properties to breakup processes that probe a larger range of physics. To achieve this, the Lorentz Integral Transform (LIT) method is extended such that all subleading corrections, including those to the electromagnetic current operator, are included in perturbation theory, reaching second order in the EFT expansion. Finding good agreement with available data, this perturbative LIT framework paves the way for similar studies involving heavier nuclei.

Discovering new isotopes begins with knowing where to look. Predicting rare-isotope production is difficult because different nuclear-mass models can give substantially different results, making the planning of experiments uncertain. This work introduces a Bayesian-inspired model-averaging framework that combines abrasion–ablation calculations based on 12 nuclear mass tables into one statistically weighted prediction. Experimental data for krypton-78 and xenon-124 are used to determine which calculations are more reliable, and the resulting trends are transferred to molybdenum-92 and samarium-144 projectiles. The method provides predicted cross sections together with uncertainty estimates, giving a more reliable basis for selecting primary beams and estimating yields. Applied to proton-rich fragmentation at FRIB, the approach identifies several promising candidates for new-isotope searches with expected production rates above one event per day. It can help researchers plan experiments more effectively and explore still-unknown regions of the nuclear chart.

Variational methods employing symmetry-breaking intrinsic states offer alternative ways to tackle large-scale shell model calculations. While the latter provides a unified picture of the rotational motion and shell structure, the former has been known to provide a good approximation for the description of nuclear deformation. However, in such approaches, it is generally difficult to fully capture the effects of pairing correlations, for example in the backbending phenomena where the collective rotational motion is significantly disturbed. In this paper, the binding energies of levels coming from large-scale shell-model calculations are exactly reproduced using a discrete set of non-orthogonal Slater determinants, thus verifying their relevance for describing pairing properties as demonstrated in the ground-state band of 48Cr and the ground state of 78Ni, which is at the limit of conventional shell-model calculations. These results constitute a firm proof of the Broeckhove-Deumens theorem on the completeness property of non-orthogonal wave functions in realistic shell-model calculations.

The authors present both qualitative and quantitative advances in extracting transport coefficients and other parameters for the quark-gluon plasma formed in heavy ion collisions. The manuscript uses extensive data sets from all four of the original RHIC experiments to calibrate the input to a full 3-dimensional simulation based on relativistic hydrodynamics. The authors consider both a large system (Au+Au) as well as several small systems (d+Au, p+Au and ${}^3$He+Au). The success in describing small systems provides strong support for the hydrodynamic paradigm, and also helps resolve a long-standing puzzle between STAR and PHENIX measurements in such systems.

Spin utilization in large particle accelerators is a young quantum technology, with practical realization only emerging in the late twentieth century. Polarized ion beams at the future Electron Ion Collider (EIC) are essential to address some of the most important open questions at the twenty-first-century frontiers of our understanding of the fundamental structure of matter. How does the proton spin of $1/2$ arise from the highly relativistic constituent quarks and gluons and their interactions via QCD? Are the quark and gluon nucleon spin distributions modified inside the nucleus? Can exotic gluons exist in the nucleus? Beyond these questions, polarized electron and ion beams are crucial for unravelling the full three-dimensional structure of the nucleon and of nuclei. This Perspective paper summarizes the science case and identifies polarized ion beams as the critical technology enabling the experiments that address these questions. The authors further discuss the required ion polarimetry and spin manipulation at the EIC, and identify a significant R&D effort, involving both national laboratories and universities, that will be required over roughly a decade to realize the polarized ion beams.