Thu·Nov 14, 2024Thursday·November 14, 2024

1. 01*

   Neutrino mass experiments: current and future

   Larisa A. Thorne🇩🇪

   Nearly 70 years since the neutrino was discovered, and 25 years since discovery of neutrino oscillations established its non-zero mass, the absolute neutrino-mass scale remains unknown. Due to its unique characteristics, determining this neutrino property requires new measurement techniques to be developed. Currently, there are four measurement approaches: using cosmological models, inference from time-of-arrival from supernovae, through observation of neutrinoless double beta decay, and the kinematics of weak decay processes. I will review the theoretical basis underlying neutrino mass measurement and present key experiments in this field. I will highlight the current best upper limits, how neutrino mass experiments are complementary to other neutrino property searches, and summarize the challenges that lie ahead of the neutrino mass community.

   nucl-exEPJ Web Conf.(2024)·2 citations
2. 02*

   High-temperature ${}^{205}$Tl decay clarifies ${}^{205}$Pb dating in early Solar System

   G. Leckenby🇨🇦 · R. S. Sidhu🇩🇪 · R. J. Chen🇩🇪 · R. Mancino🇨🇿 · B. Szányi🇭🇺 · M. Bai🇩🇪 · U. Battino🇬🇧 · K. Blaum🇩🇪 · C. Brandau🇩🇪 · S. Cristallo🇮🇹 · T. Dickel🇩🇪 · I. Dillmann🇨🇦 and 47 other authors

   Radioactive nuclei with lifetimes on the order of millions of years can reveal the formation history of the Sun and active nucleosynthesis occurring at the time and place of its birth. Among such nuclei whose decay signatures are found in the oldest meteorites, ${}^{205}$Pb is a powerful example, as it is produced exclusively by slow neutron captures (the s process), with most being synthesized in asymptotic giant branch (AGB) stars. However, making accurate abundance predictions for ${}^{205}$Pb has so far been impossible because the weak decay rates of ${}^{205}$Pb and ${}^{205}$Tl are very uncertain at stellar temperatures. To constrain these decay rates, we measured for the first time the bound-state ${\beta }^{-}$ decay of fully ionized ${}^{205}$Tl${}^{81+}$, an exotic decay mode that only occurs in highly charged ions. The measured half-life is 4.7 times longer than the previous theoretical estimate and our 10% experimental uncertainty has eliminated the main nuclear-physics limitation. With new, experimentally backed decay rates, we used AGB stellar models to calculate ${}^{205}$Pb yields. Propagating those yields with basic galactic chemical evolution (GCE) and comparing with the ${}^{205}$Pb/${}^{204}$Pb ratio from meteorites, we determined the isolation time of solar material inside its parent molecular cloud. We find positive isolation times that are consistent with the other s-process short-lived radioactive nuclei found in the early Solar System. Our results reaffirm the site of the Sun's birth as a long-lived, giant molecular cloud and support the use of the ${}^{205}$Pb--${}^{205}$Tl decay system as a chronometer in the early Solar System.

   nucl-exastro-ph.EPastro-ph.SRNature(2024)·15 citations
3. 03*

   Triaxial nuclear shapes from simple ratios of electric-quadrupole matrix elements

   Elena Atanassova Lawrie🇿🇦 · José Nicolás Orce🇿🇦

   Theoretical models often invoke triaxial nuclear shapes to explain elusive collective phenomena, but such assumptions are usually difficult to confirm experimentally. The only direct measurements of the nuclear axial asymmetry $\gamma$ is based on rotational invariants of zero-coupled products of the electric-quadrupole (E2) operator, the Kumar-Cline sum rule analysis, which generally require knowledge of a large number of E2 matrix elements connecting the state of interest. We propose an alternative assumptions-free method to determine $\gamma$ of even-even rotating nuclei using only two E2 matrix elements, which are among the easiest to measure. This approach is based on a simple description of nuclear rotation, where the underlying assumptions of the Davydov-Filippov model are either empirically proven or unnecessary. The $\gamma$ values extracted here are found in agreement with the values deduced from Kumar-Cline sum rules measurements (where available), providing further evidence that the proposed approach represents a reliable, model-independent deduction of $\gamma$. The technique was applied to more than 60 deformed even-even rotating nuclei and the results indicate that rotating nuclei generally exhibit well-defined stable axially-asymmetric shapes.

   ↳ nucl-thnucl-exAtom.Data Nucl.Data Tabl.(2025)·3 citations
4. 04*

   Pion Nuclear Fragmentation Functions Revisited

   Matias Doradau🇦🇷 · Ramiro Tomas Martinez🇦🇷 · Rodolfo Sassot🇦🇷 · Marco Stratmann🇩🇪

   We revisit the notion of nuclear parton-to-pion fragmentation functions at next-to-leading order accuracy as an effective description of hadroproduction in nuclear environments such as in semi-inclusive lepton-nucleus deep-inelastic scattering and in single inclusive proton-nucleus collisions. We assess their viability in the face of very precise data collected for the latter at the CERN-LHC over the past decade as well as recent measurements of the former carried out by the CLAS experiment at JLab.

   ↳ hep-phhep-exnucl-exPRD(2025)·6 citations
5. 05*

   Investigating the possibility of extracting neutron-skin thickness in nuclei by their collisions at intermediate energies

   Tian-Ze Li · Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Zhong-Zhou Ren🇨🇳

   Inspired by various studies on extracting the density distributions of nuclei from their collisions at ultrarelativistic energies, in the present work we investigate the possibility of extracting the neutron-skin thickness $\Delta r_{np}$ in nuclei by their collisions at intermediate energies. We have analyzed the free neutron-to-proton yield ratio $n/p$ as a candidate probe at both midrapidities and forward rapidities in peripheral and central ${}^{124}$Sn+${}^{124}$Sn collisions based on an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, and found that the resulting $n/p$ yield ratio is more sensitive to the symmetry potential in the collision dynamics than to the initial $\Delta r_{np}$ in colliding nuclei in most cases. The largest effect on the $n/p$ yield ratio from the initial $\Delta r_{np}$ is observed for nucleons at large transverse or longitudinal momenta in central collisions at the collision energy of a few GeV/nucleon.

   ↳ nucl-thnucl-exPRC(2024)·1 citation
6. 06*

   Multiple shape coexistence in the $N=Z$ ${}^{84}$Mo nucleus

   Tomás R. Rodríguez🇪🇸

   The structure of the nucleus ${}^{84}$Mo has been studied using the projected generator coordinate method (PGCM) with the Gogny D1S interaction. The calculations incorporate a mixing of particle-number and angular-momentum projected intrinsic wave functions, defined over triaxial quadrupole degrees of freedom. This approach yields an excellent agreement with the scarce experimental data for this nucleus and several bands based on different shapes are predicted.

   ↳ nucl-thnucl-exEPJ Web Conf.(2025)·0 citations
7. 07*

   Imaging Freeze-out Sources and Extracting Strong Interaction Parameters in Relativistic Heavy-Ion Collisions

   Junhuai Xu🇨🇳 · Zhi Qin🇨🇳 · Renjie Zou🇨🇳 · Dawei Si🇨🇳 · Sheng Xiao🇨🇳 · Baiting Tian🇨🇳 · Yijie Wang🇨🇳 · Zhigang Xiao

   By combining femtoscopic interferometry with an optical deblurring algorithm, we present a novel method to image the source in heavy-ion collisions (HICs) while simultaneously determining the interaction strength between particle pairs. The spatial distribution of the emission source has been reconstructed for protons ($p$) and antiprotons ($\bar{p}$) from the respective $pp$ and $\bar{p}\bar{p}$ correlation functions in Au+Au collisions at $\sqrt{S_{\mathrm{NN}}}=200$ GeV. Within experimental uncertainties, protons and antiprotons share the same freeze-out distribution showing higher density in the center compared to the widely assumed Gaussian shape. The results evidence the matter-antimatter symmetry in coordinate space at the moment of freeze-out before the nucleons are fully randomized in the collisions.

   ↳ nucl-thnucl-exChin.Phys.Lett.(2025)·19 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.