Wed·Oct 15, 2025Wednesday·October 15, 2025

1. 01*

   The mass of ${}^{101}$Sn and Bayesian extrapolations to the proton drip line

   Christian M. Ireland🇺🇸 · Georg Bollen🇺🇸 · Scott E. Campbell🇺🇸 · Xiangcheng Chen🇺🇸 · Hannah Erington🇺🇸 · Nadeesha D. Gamage🇺🇸 · Kyle Godbey🇺🇸 · Alicen M. Houff🇺🇸 · Christopher Izzo🇺🇸 · Bailey Knight · Sudhanva Lalit🇺🇸 · Erich Leistenschneider🇺🇸 and 14 other authors

   The favorable energy configurations of nuclei at magic numbers of $N$ neutrons and $Z$ protons are fundamental for understanding the evolution of nuclear structure. The $Z=50$ (tin) isotopic chain is a frontier for such studies, with particular interest at and around the doubly-magic \textsuperscript{100}Sn isotope, for which the mass is a topic of debate. Precise mass values for neutron-deficient isotopes provide necessary anchor points for mass models to test extrapolations near the proton drip line, where experimental studies remain out of reach. In this work, we report the first Penning trap mass measurement of \textsuperscript{101}Sn. The determined mass excess of $-59889.89(96)$~keV for \textsuperscript{101}Sn represents a factor of 300 improvement over the current precision and indicates that \textsuperscript{101}Sn is less bound than previously thought. Mass predictions from a recently developed Bayesian model combination (BMC) framework employing statistical machine learning and nuclear masses computed within seven global models based on nuclear Density Functional Theory (DFT) agree within 1$\sigma$ with experimental masses from the $48\le Z\le 52$ isotopic chains. The framework's resilience to new mass data gave confidence in the extrapolation of tin masses down to $N=46$. Our calculations suggest that \textsuperscript{96}Sn is a two-proton drip line nucleus and predict a mass excess of $-58090(800)$~keV for ${}^{100}$Sn, showing a preference within 1$\sigma$ for the mass of \textsuperscript{100}Sn derived from the $\beta$-delayed $Q$-value measured at GSI.

   nucl-exnucl-thPRC(2026)·6 citations
2. 02*

   Stellar s-process neutron capture cross sections on A-Se and A-Ce

   R. N. Sahoo · M. Tessler · S. Halfon · Y. Kashiv · D. Kijel · A. Kreisel · M. Paul · A. Shor · L. Weissman

   We report on experiments at the Soreq Applied Research Accelerator Facility - Liquid-Lithium Target (SARAF-LiLiT) laboratory dedicated to the study of s-process neutron capture reactions. The kW-power proton beam at 1.92 MeV (1-2 mA) from SARAF Phase I yields high-intensity 30 keV quasi-Maxwellian neutrons (3-5x10^10 n/s). The high neutron intensity enables Maxwellian averaged cross sections (MACS) measurements of samples with short-lived decay products. Neutron capture reactions on nat-Se and nat-Ce were investigated by activation in the LiLiT neutron beam and {\gamma}-spectrometry measurements of their decay products.

   nucl-exEPJ Web Conf.(2023)·1 citation
3. 03*

   CE$\nu$NS Search with Cryogenic Sapphire Detectors at MINER: Results from the TRIGA reactor data and Future Sensitivity at HFIR

   D. Mondal🇮🇳 · W. Baker🇺🇸 · M. Chaudhuri🇮🇳 · J. B. Dent🇺🇸 · R. Dey🇮🇳 · B. Dutta🇺🇸 · V. Iyer🇨🇦 · A. Jastram🇺🇸 · V. K. S. Kashyap🇮🇳 · A. Kubik🇨🇦 · K. Lang🇺🇸 · R. Mahapatra🇺🇸 and 11 other authors

   We report on a search for coherent elastic neutrino--nucleus scattering (CE$\nu$NS) using cryogenic sapphire (Al${}_2$O${}_3$) detectors deployed at the Mitchell Institute Neutrino Experiment at Reactor (MINER), located near the 1~MW${}_{\text{th}}$ TRIGA research reactor at Texas A\&M University. The experiment operated with a primary detector mass of 72~g and achieved a baseline energy resolution of $\sim 40$~eV. Using exposures of 158~g-days (reactor-on) and 381~g-days (reactor-off), we performed a statistical background subtraction in the energy region of 0.25--3~keV. A GEANT4 simulation has been performed to understand the reactor-correlated background present in the data and it agrees with our observations. The resulting best-fit ratio of the observed CE$\nu$NS rate to the Standard Model prediction after rejecting the reactor induced background from the data with the help of simulation, is $\rho =0.26\pm 1534.74(\mathrm{stat})\pm 0.05(\mathrm{sys})$ with a significance of $0.007\pm 0.022(\mathrm{stat})\pm 0.001(\mathrm{sys})$. This low significance indicates a high background rate at low energies. To have enhanced sensitivity, the MINER collaboration plans to relocate the experiment to the 85~MW${}_{\text{th}}$ High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). With improved shielding, increased detector mass, and higher antineutrino flux, the upgraded setup is projected to achieve a 3$\sigma$ CE$\nu$NS detection within 30~kg$\cdot$days of exposure.

   nucl-exhep-exnucl-thphysics.ins-detPRD(2026)·6 citations
4. 04*

   New Spallation Background Rejection Techniques to Greatly Improve the Solar Neutrino Sensitivity of JUNO

   Obada Nairat🇺🇸 · John F. Beacom🇺🇸 · Shirley Weishi Li🇺🇸

   While the potential of the Jiangmen Underground Neutrino Observatory (JUNO) to measure solar neutrinos is known, realizing this potential requires new techniques to reduce detector backgrounds. One of the most serious backgrounds is due to the beta decays of unstable nuclei produced through muon breakup (spallation) of nuclei. This background is much more significant in JUNO compared to Super-Kamiokande due to JUNO's shallower depth and its lack of directional information. We present the first detailed theoretical calculations of spallation backgrounds in JUNO, showing the underlying physical processes and new ways to cut backgrounds while preserving signals. A key point is showing the importance of neutron tagging to identify hadronic showers, which are rare but produce almost all of the dangerous isotopes. With our new techniques, JUNO will be able to reduce deadtime (signal loss) by a factor of about 4.5 and to reduce the running time needed to meet sensitivity goals by a factor of two. This will give JUNO greatly improved sensitivity to ${}^8$B and $hep$ solar neutrinos, as we will explore in a separate paper.

   ↳ hep-phastro-ph.HEhep-exnucl-ex+2PRD(2026)·3 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.