Mon·Aug 25, 2025Monday·August 25, 2025

1. 01*

   News from NA61/SHINE

   Katarzyna Grebieszkow (for the NA61/SHINE Collaboration)🇵🇱

   The main goal of the NA61/SHINE strong interaction program is to search for the critical point in the phase diagram of strongly interacting matter and to investigate phenomena related to the onset of deconfinement. In recent years, the program has expanded to include the study of open charm, aiming to understand the mechanisms of its production in heavy-ion collisions. This article presents a selection of recent results from the NA61/SHINE strong interaction program, including findings on particle spectra and yields, as well as fluctuations and correlations. Plans for the near future are also discussed.

   nucl-exEPJ Web Conf.(2026)·0 citations
2. 02*

   First Full Dalitz Plot Measurement in Neutron $\beta$-Decay using the Nab Spectrometer and Implications for New Physics

   Francisco M. Gonzalez · Jin Ha Choi · Himal Acharya · Skylar Clymer · Andrew Hagemeier · David G. Mathews · August Mendelsohn · Austin Nelsen · Hitesh Rahangdale · Love Richburg · Ricardo Alarcon · Ariella Atencio and 80 other authors

   Precision measurements of observables in neutron $\beta$-decay are used to test the Standard Model description of the weak interaction and search for evidence of new physics. The Nab experiment at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source was constructed to measure correlations in neutron decay by utilizing an asymmetric spectrometer and novel detection system to accurately reconstruct the proton momentum and electron energy for each $\beta$-decay. This work describes the detection of neutron $\beta$-decay products in the Nab spectrometer and presents the first full Dalitz plot representation of the phase space of neutron $\beta$-decay for all electrons >100 keV. In addition, new constraints are placed on a possible excited neutron state, hypothesized to explain the disagreement between the appearance and disappearance neutron lifetime techniques.

   nucl-exhep-exPRC(2026)·4 citations
3. 03*

   Precision Measurements of the Neutron Magnetic Form Factor to High Momentum Transfer using Durand's Method

   Provakar Datta🇺🇸

   Elastic electron-nucleon scattering provides insights into the spatial distributions of charge and current within nucleons through their electromagnetic form factors. Accurate knowledge of these form factors over a broad range of $Q^2$, the squared four-momentum transfer in the scattering process, reveals details about the nucleon's internal structure. However, high-$Q^2$ data of the nucleon electromagnetic form factor is scarce due to the challenges associated with such measurements. This thesis reports preliminary results from high-precision measurements of the neutron magnetic form factor ($G_M^n$) to unprecedented $Q^2$ using Durand's method, also known as the "ratio" method. Systematic errors are greatly reduced by extracting $G_M^n$ from the ratio of neutron-coincident ($D(e,e^{\prime }n)$) to proton-coincident ($D(e,e^{\prime }p)$) quasi-elastic electron scattering from deuteron. The scattered electrons were detected in the BigBite spectrometer, which features multiple Gas Electron Multiplier (GEM) layers with large active area for high-precision tracking at very high rates. Simultaneous nucleon detection was performed by the Super BigBite spectrometer, which utilizes a dipole magnet with large solid angle acceptance at forward angles and a novel hadron calorimeter with very high and comparable detection efficiencies for both protons and neutrons. This setup could handle very high luminosity, making high-$Q^2$ measurements feasible. Data were collected at five $Q^2$ points: $3,$ $4.5,$ $7.4,$ $9.9,$ and $13.6$ (GeV/c)${}^2$. Preliminary results are reported for all, with the lowest two $Q^2$ points in good agreement with existing world data, while the higher points significantly extend the $Q^2$ range in which $G_M^n$ is known accurately. The precision of the highest $Q^2$ point is expected to remain unmatched for years to come.

   nucl-exhep-ex1 citation
4. 04*

   Detectability of Covert Fissile Material Production in Nuclear Fusion Reactors via Antineutrino Emissions

   Alexander Glaser · Robert J. Goldston · Patrick Huber🇺🇸

   Fusion power systems can in principle be used to make significant amounts of fissile material. To do so, an operator would have to introduce fertile material, such as uranium-238, in a suitable region of the reactor where it is exposed to an intense neutron flux. The possibility of using a fusion reactor for this purpose has raised the question of how these facilities can be monitored to ensure their peaceful use. This study examines whether covert production of fissile material in a declared fusion plant could be detected with an onsite antineutrino detector. We find that even a relatively small detector should be able to confirm production rates of a few kilograms of plutonium over 30 days, despite the cosmogenic background and the antineutrino emissions associated with neutron activation of reactor components.

   ↳ physics.ins-detnucl-exPhys.Rev.Applied(2026)·1 citation

* 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.