Fri·Oct 25, 2024Friday·October 25, 2024

1. 01*

   Measurement of the mass-changing, charge-changing and production cross sections of ${}^{11}$C, ${}^{11}$B and ${}^{10}$B nuclei in ${}^{12}$C+p interactions at 13.5 GeV/c per nucleon

   NA61/SHINE Collaboration

   We report results from a 2018 pilot run to study the feasibility of nuclear fragmentation measurements with the NA61/SHINE experiment at the CERN SPS. These results are important for the interpretation of the production of light secondary cosmic-ray nuclei (Li, Be, and B) in the Galaxy. The specific focus here is on cross sections important for the production of boron in the Galaxy from the interactions of ${}^{12}$C nuclei with hydrogen in the interstellar medium, including the contribution from the decay of the short-lived ${}^{11}$C fragments. The data were taken with the secondary ${}^{12}$C beam at beam momentum of 13.5 GeV/c per nucleon and two fixed targets, polyethylene (CH${}_2$) and graphite (C), from which we derive the cross sections of carbon on hydrogen. We present the measurement of the fragmentation cross sections of ${}^{11}$C, ${}^{11}$B, and ${}^{10}$B as well as the mass- and charge-changing cross sections.

   nucl-exastro-ph.HEPRC(2025)·8 citations
2. 02*

   Effects of incompressibility on the neutron-proton equilibration in ${}^{70}$Zn + ${}^{70}$Zn collisions at 35 MeV/nucleon

   Erxi Xiao🇨🇳 · Yu Yang · Yingge Huang🇨🇳 · Zhen Zhang🇨🇳 · Long Zhu🇨🇳 · Jun Su🇨🇳

   Background: The primary goal of studying isospin dynamics via heavy-ion reactions is to explore the isospin dependence of effective interactions within the nuclear equation of state (EOS). Purpose: This work aims to investigate the effects of nuclear incompressibility ($K_0$) on neutron-proton equilibration in projectile-like fragments (PLFs). Method: We simulate ${}^{70}$Zn + ${}^{70}$Zn collisions at 35 MeV/nucleon using the isospin-dependent quantum molecular dynamics (IQMD) model, coupled with the statistical decay code GEMINI. Results: The IQMD simulations not only reproduce experimental data patterns but also reveal the dynamic mechanisms underlying the binary breakup of PLFs. The rotation of PLFs is influenced by the transformation of angular momentum, which is connected to the isoscalar component of the EOS. This connection explains why shifts in $K_0$ affect the description of neutron-proton equilibration as measured by PLF rotation. The simulations demonstrate that a model with a smaller $K_0$ paired with a softer symmetry energy, or a larger $K_0$ with a slightly stiffer symmetry energy, both offer better indications of neutron-proton equilibration. Conclusion: Considering the uncertainty in $K_0$, the slope of the symmetry energy is constrained within the range of $L=20\sim 40$ MeV, providing valuable insights into the nuclear equation of state.

   ↳ nucl-thnucl-exPRC(2025)·0 citations
3. 03*

   Long term remote reactor power and fuel composition monitoring using antineutrinos

   I. Alekseev🇷🇺 · V. Belov🇷🇺 · A. Bystryakov🇷🇺 · M. Danilov🇷🇺 · D. Filosofov🇷🇺 · M. Fomina🇷🇺 · P. Gorovtsov🇷🇺 · Ye. Iusko🇷🇺 · S. Kazartsev🇷🇺 · V. Khvatov🇷🇺 · S. Kiselev🇷🇺 · A. Kobyakin🇷🇺 and 22 other authors

   Electron antineutrinos are emitted in the decay chains of the fission products inside a reactor core and could be used for remote monitoring of nuclear reactors. The DANSS detector is placed under the core of the 3.1 GW power reactor at the Kalinin Nuclear Power Plant (KNPP) and collects up to 5000 antineutrino events per day. DANSS measured changes of the reactor power by antineutrino counting rates over 7 years with 1.0% accuracy in one week periods. The fission fractions of four major isotopes for the reactor power calculations were provided by KNPP. The systematic uncertainty of this measurement is less than 0.8%. It is comparable to the accuracy of conventional methods of the reactor power measurements while it is based on completely different approach. For the first time the 239Pu and 235U fission fractions were reconstructed using antineutrino inverse beta-decay spectrum which is a completely new technique. This method was applied to the data from three reactor fuel campaigns (approximately 1.5 year each). The reconstructed fission fractions in about two-week measurements and the fission fractions provided by KNPP coincide within better than 3% accuracy. This provides confidence in both completely different approaches of the fission fraction determination.

   ↳ hep-exnucl-exphysics.ins-detPLB(2025)·5 citations
4. 04*

   Optimizing Spin Dressing Sensitivity for the nEDMSF Experiment

   V. Cianciolo🇺🇸

   nEDMSF aims to measure the neutron electric dipole moment ($d_n$) with unprecedented precision. In this paper we explore the experiment's sensitivity when operating with an implementation of the critical dressing method in which the angle between the neutron and Helium-3 spins (${\varphi }_{3n}$) is subjected to a square modulation by an amount ${\varphi }_d$ (the "dressing angle"). Several parameters can be tuned to optimize sensitivity. We find roughly 10% improvement over a previous estimate, resulting primarily from the addition of a waiting period between the $\pi /2$ pulse that initiates $d_n$-driven ${\varphi }_{3n}$ growth and the start of ${\varphi }_{3n}$ modulation. We find negligible further improvement by allowing ${\varphi }_d$ to vary continuously over the course of a run, and no degradation resulting from the addition of an in situ background measurement into each ${\varphi }_{3n}$ modulation sequence. A complete simulation confirms a 300 live-day sensitivity of $\sigma =1.45\times 10^{-28}e\cdot \mathrm{cm}$. At this level of sensitivity, ${\sigma }_{{\varphi }_{3n0}}=1\mathrm{mrad}$ precision on the initial $n{/}^3\mathrm{He}$ angle difference is not negligible.

   ↳ physics.ins-detnucl-exJINST(2025)·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.