Nuclear Experiment·nucl-ex

Mon·Aug 17, 2026Monday·August 17, 2026

3 papers—2 primary·1 cross-listed

01
Observing the effects of numbers of valence nucleons on $0_{g s}^{+} \to 2_{1}^{+}$ transitions in deformed nuclei by comparing proton and neutron transition matrix elements
P. D. Cottle🇺🇸 · L. A. Riley🇺🇸 · A. Gade🇺🇸 · K. W. Kemper🇺🇸 · M. Spieker🇺🇸
We examined the ratios of neutron and proton transition matrix elements, $M_{n} / M_{p}$ , for the $0_{g s}^{+} \to 2_{1}^{+}$ transitions in 48 even-even stable nuclei with $N > 20$ for which electromagnetic matrix elements were compiled by Pritychenko \textit{et al.} and for which high-quality inelastic proton scattering data were available. Several deformed rare earth nuclei have $(M_{n} / M_{p}) / (N / Z)$ values significantly below 1.0, which is not consistent with a simple liquid drop picture. However, this phenomenon can be explained using a schematic picture in which $M_{p}$ reaches a maximum at proton mid-shell ( $Z = 66$ ) and $M_{n}$ reaches its maximum at neutron mid-shell ( $N = 104$ ). Several mid-mass vibrational nuclei have $M_{n} / M_{p}$ values significantly below $N / Z$ , which is not consistent with the expectation that $M_{n} / M_{p} = N / Z$ in such nuclei. A shell model investigation of these observations might yield insights about this behavior.
nucl-exPRC(2026)·0 citations
02
Extraction of Neutron-Skin Parameters in Zr+Zr and Ru+Ru Collisions at $s_{NN}$ = 200 GeV
Junjian Zhou🇨🇳 · Dongsheng Li🇨🇳 · Fan Si🇨🇳 · Xiujun Li🇨🇳 · Yifei Zhang🇨🇳
The initial nuclear geometry of colliding nuclei, manifested in proton and neutron density profiles, plays a key role in determining final-state effects in high-energy heavy-ion collisions. We study $^{96} Ru +^{96} Ru$ and $^{96} Zr +^{96} Zr$ collisions at $s_{NN} = 200$ GeV incorporating an isospin-dependent Woods-Saxon distribution to account for neutron-skin effects in the UrQMD model. By systematically scanning the proton surface diffuseness parameter $a_{p,Zr}$ of the $^{96} Zr$ nucleus and performing a $χ^{2}$ analysis by comparing with STAR experimental data, we extract the relative neutron-skin thickness difference $0.278 \pm 0.018$ fm between the two isobaric systems using the net-charge yield difference $Δ Q$ . We further show that the neutron-skin effect evidently modifies the baryon-to-charge transport ratio $R_{B / Q} = ⟨ B ⟩ /Δ Q \times Δ Z / A$ , and substantially influences the observed $R_{B / Q} > 1$ behavior in central collisions. This work indicates that nuclear structure effects contribute non-negligibly to baryon transport observables without a baryon junction hypothesis, and underscores the importance of precise initial-state geometry constraints for exploring novel QCD phenomena in relativistic heavy-ion collisions.
nucl-ex0 citations
03
Optical Characterization Measurements of Commercial Polyvinyltoluene Scintillators for Accurate Geant4 Detector Modeling
Fergus Martin Huggins · Micah S. Johnson · Matthew Quinn Buckner
Accurate Monte Carlo simulation of plastic scintillator detectors requires precise wavelength-dependent optical properties. We present the first comprehensive measurements of wavelength-dependent refractive index $n (λ)$ and bulk absorption length $L_{abs} (λ)$ for six commercial polyvinyltoluene (PVT)-based scintillators (Saint Gobain BC-400, BC-404, BC-408, BC-418, BC-422, and BC-430) across the 370-660 nm range. Using a precision refraction apparatus and variable-thickness transmission measurements, we characterize material-specific dispersion that deviates substantially from both the manufacturer specification and literature values for pure PVT. Validation simulations of a BC-422 detector demonstrate a 7.2% reduction in detected photon counts when using our measured $n (λ)$ compared to the constant manufacturer value, highlighting the practical importance of accurate optical property data for detector design and calibration. We successfully measure absorption lengths for BC-430 across most of the visible spectrum (2.2-12.4 mm) and for all materials at 372 nm (21-38 mm), while establishing lower bounds exceeding 750 mm for weakly absorbing formulations at longer wavelengths.
↳ physics.ins-dethep-exnucl-exphysics.optics0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Observing the effects of numbers of valence nucleons on 0gs+​→21+​ transitions in deformed nuclei by comparing proton and neutron transition matrix elements

Extraction of Neutron-Skin Parameters in Zr+Zr and Ru+Ru Collisions at sNN​​ = 200 GeV

Optical Characterization Measurements of Commercial Polyvinyltoluene Scintillators for Accurate Geant4 Detector Modeling

Affiliations

Observing the effects of numbers of valence nucleons on $0_{g s}^{+} \to 2_{1}^{+}$ transitions in deformed nuclei by comparing proton and neutron transition matrix elements

Extraction of Neutron-Skin Parameters in Zr+Zr and Ru+Ru Collisions at $s_{NN}$ = 200 GeV