Nuclear Experiment·nucl-ex

Wed·Jul 8, 2026Wednesday·July 8, 2026

5 papers—3 primary·2 cross-listed

01
$K^{*} (892)^{0}$ production and the time between freeze-outs in $^{40}$ Ar+ $^{45}$ Sc collisions by NA61/SHINE at the CERN SPS
NA61/SHINE Collaboration: P. Adrich · K.K. Allison · M. Bajda · Y. Balkova · D. Battaglia · M. Bielewicz · A. Blondel · M. Bogomilov · Y. Bondar · J. Brzychczyk · M. Buryakov · A.F. Camino and 99 other authors
The analysis of the production of strange $K^{*} (892)^{0}$ resonances allows us to better understand the temporal evolution of high-energy nucleus--nucleus collisions. In particular, the ratio of $K^{*} (892)^{0}$ to charged kaon yields is used to determine the time interval between chemical and kinetic freeze-outs. In this paper, the first measurements of $K^{*} (892)^{0}$ production in central $^{40}$ Ar+ $^{45}$ Sc collisions at the CERN Super Proton Synchrotron are reported. They were performed by NA61/SHINE at collision center-of-mass energies per nucleon pair $s_{NN}$ = 8.8, 11.9, 16.8 GeV. The obtained $⟨ K^{*} (892)^{0} ⟩ / ⟨ K^{+} ⟩$ and $⟨ K^{*} (892)^{0} ⟩ / ⟨ K^{-} ⟩$ mean multiplicity ratios are compared with corresponding results in $p$ + $p$ collisions, allowing for an estimate of the time interval between chemical and thermal freeze-outs in the $^{40}$ Ar+ $^{45}$ Sc system. These are the first such results reported for $^{40}$ Ar+ $^{45}$ Sc collisions.
nucl-exhep-ex0 citations
02
Interplay between Nuclear Shell Structure and Pairing around Doubly Magic $^{132}$ Sn
Rane Simpson · Georgios Palkanoglou · Ellen Brisley🇨🇦 · Jaime Cardona🇨🇦 · Annabelle Czihaly🇨🇦 · Sakshi Kakkar🇨🇦 · Makar Simonov · Ethan Taylor🇨🇦 · Coulter Walls🇨🇦 · Pavithra Weligampola🇨🇦 · Chris Chambers🇨🇦 · Fernando Maldonado Millan🇨🇦 and 11 other authors
Shell structure in finite quantum systems gives rise to sudden changes in observable properties, while pairing correlations often compete against such discontinuities. The region near the doubly magic nucleus $^{132}$ Sn provides a fertile ground for testing the combined effect of shell structure and pairing. Here, we provide a novel phenomenological interpretation of existing mass data in the vicinity of the $Z = 50$ and $N = 82$ shell closures, which we further investigate by performing original Hartree-Fock-Bogolyubov (HFB) mean-field calculations for even- $Z$ nuclei: we find that the proton shell structure enhances an asymmetry of the neutron odd-even staggering in binding energies. We also report mass measurements of $^{137, 138}$ Sb, including the first experimental mass determination of $^{138}$ Sb, performed using TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN). Together with existing experimental data, our results reveal an interplay between shell structure and pairing in odd- $Z$ nuclei which is more challenging to interpret phenomenologically or using HFB, thereby motivating future experimental and theoretical pairing studies in heavy neutron-rich nuclides.
nucl-exnucl-th1 citation
03
A New Low $Q^{2}$ Measurement of the Proton's $g_{1}$ Spin Structure Function from Longitudinal & Transverse Polarized Data
D. Ruth · R. Zielinski · C. Gu · M. Allada · T. Badman · M. Huang · J. Liu · P. Zhu · K. Allada · J. Zhang · A. Camsonne · J.P. Chen and 85 other authors
The proton's spin structure has proven to be far more complicated than was originally believed, and has been the subject of a number of experimental investigations. %Early measurements of the proton's spin structure function $g_{1}$ showed that the proton does not solely derive its spin from the spins of its quarks, starting the `proton spin crisis'. Of particular interest are the spin structure functions $g_{1}$ and $g_{2}$ , which can be used to generate moments to directly compare experimental results to Chiral Perturbation Theory and other theories of Quantum Chromodynamics (QCD). The proton's $g_{1}$ structure function has been the subject of two other recent low momentum transfer experiments, but there are currently no published low momentum transfer measurements which collected data on the proton structure functions using both a longitudinally-polarized and a transversely-polarized target at the same kinematics. In this paper, we present the longitudinally polarized results of the Jefferson Lab E08-027 experiment, along with linked moments which combine this new result with the previously published transversely-polarized data from the same experiment. These results provide a proton $g_{1}$ extraction measured with very high precision across the resonance region, and provide new information on the value of $g_{1}$ dependent sum rules and moments.
nucl-exhep-ex0 citations
04
Full configuration interaction quantum Monte Carlo for accurate $ab initio$ nuclear structure calculations: algorithms and calculation details
Rongzhe Hu🇨🇳 · Furong Xu🇨🇳 · Baishan Hu🇺🇸 · Ali Alavi🇮🇷
Full configuration interaction quantum Monte Carlo (FCIQMC) is a stochastic many-body solver that has been widely applied to electronic, molecular, and condensed-matter systems. In this work we apply FCIQMC to $ab initio$ nuclear structure calculations using interactions derived from chiral effective field theory. We describe the algorithm in detail, including imaginary-time propagation, excitation generation, estimator choices, the initiator approximation with adaptive shift correction, and reduced-density-matrix (RDM) sampling. Benchmark calculations in small model spaces, where deterministic full configuration interaction (FCI) results are available, validate the stochastic calculation of energies, radii, and RDM-based pure estimators. For large model spaces, we analyze the residual finite-walker bias through systematic walker-number convergence and infinite-walker extrapolations. We also demonstrate that FCIQMC can be extended beyond ground-state calculations by computing the low-lying spectrum of $^{6}$ Li.
↳ nucl-thnucl-ex0 citations
05
Gamma Backgrounds for Experiments at the High Flux Isotope Reactor
M. Andriamirado🇺🇸 · A. B. Balantekin🇺🇸 · C. Baldenegro🇮🇹 · C. D. Bass🇺🇸 · O. Benevides Rodrigues🇺🇸 · E. P. Bernard🇺🇸 · N. S. Bowden🇺🇸 · C. D. Bryan🇺🇸 · R. Carr🇺🇸 · T. Classen🇺🇸 · A. J. Conant🇺🇸 · N. Craft🇺🇸 and 44 other authors
This article describes the deployment of a germanium detector at Oak Ridge National Lab's High Flux Isotope Reactor (HFIR) for the purpose of understanding the energy and spatial distribution of the gamma field in the experiment hall where the Precision Reactor Oscillation and Spectrum Experiment (PROSPECT) took data and future neutrino experiments could be located. The sources from both the reactor and the neutron beamlines are described in detail, along with their temporal variations due to reactor power and their spatial variations due to the geometry of the beamlines and building materials in the vicinity. Additionally, a shielding study was performed to assess the amount that backgrounds in tens of keV range can be mitigated. This work helps inform backgrounds for future experiments at reactors such as IBD-based neutrino measurements and CEvNS measurements.
↳ hep-exnucl-ex0 citations

Affiliations

first authorsco-authorsvia INSPIRE

K∗(892)0 production and the time between freeze-outs in 40Ar+45Sc collisions by NA61/SHINE at the CERN SPS

Interplay between Nuclear Shell Structure and Pairing around Doubly Magic 132Sn

A New Low Q2 Measurement of the Proton's g1​ Spin Structure Function from Longitudinal & Transverse Polarized Data

Full configuration interaction quantum Monte Carlo for accurate ab initio nuclear structure calculations: algorithms and calculation details

Gamma Backgrounds for Experiments at the High Flux Isotope Reactor

Affiliations

$K^{*} (892)^{0}$ production and the time between freeze-outs in $^{40}$ Ar+ $^{45}$ Sc collisions by NA61/SHINE at the CERN SPS

Interplay between Nuclear Shell Structure and Pairing around Doubly Magic $^{132}$ Sn

A New Low $Q^{2}$ Measurement of the Proton's $g_{1}$ Spin Structure Function from Longitudinal & Transverse Polarized Data

Full configuration interaction quantum Monte Carlo for accurate $ab initio$ nuclear structure calculations: algorithms and calculation details