Tue·Sep 9, 2025Tuesday·September 9, 2025

1. 01*

   Bayesian Analysis of the ${}^{86}$Sr$(\alpha ,\alpha )$ Reaction to Constrain the ${}^{86}$Sr$(\alpha ,n)$ Cross Section at Astrophysical Energies

   Caleb Marshall🇺🇸 · Taliah Lansing · David Gribble · Richard Longland🇺🇸 · Athanasios Psaltis🇨🇦 · Kiana Setoodehnia🇺🇸

   The Alpha Optical Model Potential (\aomp \!) is a phenomenological approach used to describe elastic scattering where multiple reaction channels are open. It is one of the most critical inputs for the calculation of thermonuclear reaction rates in explosive stellar environments, but uncertainties within the $\alpha$-OMP lead to imprecise predictions hindering comparisons between calculations and observations. In order to improve the precision of the $\alpha$-OMP, additional nuclear physics data are required. In this paper, a measurement of the ${}^{86}$Sr($\alpha$, $\alpha$) elastic scattering cross section at multiple energies is reported. A local optical potential is constructed via a fully Bayesian analysis of the elastic scattering data. The resulting uncertainties on the low energy cross sections relevant to nuclear astrophysics are then calculated and shown to be on the order of $50\%$.

   nucl-exastro-ph.SRnucl-thPRC(2025)·3 citations
2. 02*

   Extending the low-$Z$ "border'' of the $A=100$ region of deformation with precision mass spectrometry of ${}^{96-98}$Kr

   D. Lunney🇫🇷 · V. Manea🇫🇷 · M. Mougeot🇫🇮 · L. Nies🇨🇭 · N.A. Althubiti🇸🇦 · D. Atanasov🇩🇪 · K. Blaum🇩🇪 · A. Herlert🇩🇪 · W.-J. Huang🇫🇷 · J. Karthein🇩🇪 · I. Kulikov🇩🇪 · Yu. A. Litvinov🇩🇪 and 8 other authors

   The onset of collective nuclear behavior in the $N=60$, $A\sim 100$, region is examined through high-precision mass measurements of ${}^{96-98}$Kr, performed with the ISOLTRAP mass spectrometer at ISOLDE, CERN. Our results for ${}^{96-97}$Kr agree with previous measurements, with our new ${}^{97}$Kr Penning-trap mass value three times more precise. The mass value of ${}^{98}$Kr is measured for the first time. The new mass surface, together with comparisons to beyond-mean-field theoretical predictions, suggests that collectivity persists for the $Z=36$ isotopes, blurring the apparent ``low-$Z$ boundary'' of this deformed region.

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

   Quarkonia collectivity in large collision systems with ALICE

   Chi Zhang (for the ALICE collaboration)🇫🇷

   Quarkonium production is one of the golden probes to study the quark--gluon plasma (QGP). Among many observables, the measurement of azimuthal anisotropies in quarkonium production sheds light on the collective behavior of heavy-flavor particles in a strongly interacting medium. In particular, the measurements of the elliptic flow ($v_2$) of quarkonia in Pb--Pb collisions at the LHC provide us direct evidence of heavy quark thermalization in the QGP. In these proceedings, new results of inclusive $J/\psi$ elliptic flow measurement in Pb--Pb collisions carried out by the ALICE collaboration in Run 3 using three methods including event-plane, scalar-product and multi-particle correlation (cumulant) will be presented. The method of cumulant will give access to the $J/\psi$ flow fluctuations at forward rapidity. Alongside the new flow measurements of $J/\psi$, new results of $\mathrm{{\rm Y}}(1S)$ flow measurement at forward rapidity in ALICE Run 3 will be presented as well with comparison to model calculations.

   nucl-exhep-exhep-phEPJ Web Conf.(2026)·1 citation
4. 04*

   Evidence of nuclear geometry-driven anisotropic flow in OO and Ne$-$Ne collisions at $\sqrt{{\text{s}}_{\mathbf{NN}}}$ = 5.36 TeV

   ALICE Collaboration

   A central question in strong-interaction physics, governed by quantum chromodynamics (QCD), is whether femto-scale droplets of quark$-$gluon plasma (QGP) form in small collision systems involving projectiles significantly smaller than heavy ions. Collisions of light ions such as ${}^{16}$O and ${}^{20}$Ne offer a unique opportunity to probe the emergence of collective behavior in QCD matter. This Letter presents the first measurements of elliptic ($v_2$) and triangular ($v_3$) flow of charged particles in ${}^{16}$O$-$${}^{16}$O and ${}^{20}$Ne$-$${}^{20}$Ne collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_{{}_{\mathrm{NN}}}}=5.36$ TeV with the ALICE detector. The hydrodynamic model predictions, explicitly incorporating the nuclear structures of ${}^{16}$O and ${}^{20}$Ne, exhibit a good agreement with the flow measurements presented. The observed increase of $v_2$ in central Ne$-$Ne collisions relative to OO collisions, driven by the nuclear geometries, highlights the importance of utilizing light nuclei with well-defined geometric shapes to constrain the initial conditions. These findings support the presence of nuclear geometry-driven hydrodynamic flow in light-ion collisions at the LHC.

   nucl-exhep-exPRL(2026)·61 citations
5. 05*

   First Constraint on P-odd/T-odd Cross Section in Polarized Neutron Transmission through Transversely Polarized ${}^{139}$La

   Rintaro Nakabe🇯🇵 · Clayton J. Auton🇺🇸 · Shunsuke Endo🇯🇵 · Hiroyuki Fujioka🇯🇵 · Vladimir Gudkov🇺🇸 · Katsuya Hirota🇯🇵 · Ikuo Ide🇯🇵 · Takashi Ino🇯🇵 · Motoyuki Ishikado🇯🇵 · Wataru Kambara🇯🇵 · Shiori Kawamura🇯🇵 · Atsushi Kimura🇯🇵 and 18 other authors

   We report the first constraint on time-reversal invariance violating (TRIV) effects in polarized neutron transmission through a transversely polarized ${}^{139}$La target. We formulate the transmission asymmetry within the density matrix formalism, explicitly incorporating the forward scattering amplitude of ${}^{139}$La including tensor polarization terms up to third-rank. The formalism is applied to existing transmission data originally obtained to measure the spin-dependent cross section near the $0.75$~eV $p$-wave resonance. Since these data were not optimized for P-odd/T-odd observables, the attainable sensitivity is intrinsically limited; nevertheless, they provide a useful test of the formalism on real experimental data. No statistically significant TRIV signal is observed. By analyzing the global ${\chi }^2$ structure in the parameter space, we obtain an upper limit of $|W_T|<15\mathrm{eV}$ at the 90\% confidence level. This corresponds to an upper limit on the resonance-averaged TRIV cross section of $|\Delta {\sigma }_{/T/P}|<8.3\times 10^2\mathrm{b}$. These results validate the present theoretical framework and provide guidance for future dedicated TRIV searches in polarized neutron transmission experiments.

   nucl-exhep-exPTEP(2026)·1 citation
6. 06*

   Proceedings of Dielectron production in pp and Pb-Pb collisions with ALICE in Run 3, Quark Matter 2025

   Florian Eisenhut (for the ALICE Collaboration)🇩🇪

   The measurement of dielectron production is a fundamental piece of the puzzle in the understanding of the hot and dense matter produced in ultra-relativistic heavy-ion collisions. The dielectron spectrum provides information that penetrates the veil of final-state hadronic interactions and gives direct access to the early phases of the collision. However, the interpretation of the measured spectra relies on a precise understanding of all the contributing sources. The measurement of dielectron production in proton-proton collisions, collected with the upgraded ALICE detector at $\sqrt{s}$ = 13.6 TeV is presented together with the status of the Pb-Pb analysis at $\sqrt{s_{\mathrm{NN}}}$ = 5.36 TeV. In particular, the extraction of prompt (and non-prompt) dielectron spectra over a wide mass range is explained. In addition it is discussed, in which way such analysis could help to understand the Drell-Yan process in a non-perturbative regime and to investigate the onset of thermal radiation.

   nucl-exhep-exEPJ Web Conf.(2026)·1 citation
7. 07*

   Probing the cluster structure of ${}^6$Li with the nuclear reaction ${}^6$Li + ${}^{12}$C at 68 MeV

   B. A. Urazbekov · E. K. Almanbetova · A. Azhibekov · B. S. Baimurzinova · K. Dyussebayeva · T. Issatayev · D. M. Janseitov · S. M. Lukyanov · Yu. E. Penionzhkevich · K. Mendibayev · T. K. Zholdybayev

   This work presents a combined experimental and theoretical investigation of the nuclear reaction ${}^6$Li + ${}^{12}$C at a laboratory energy of 68 MeV. The reaction products are identified via the standard $\Delta$E-E technique. Angular distributions are constructed for the elastic, inelastic, and deuteron transfer channels by detecting emitted particles -- ${}^6$Li and $\alpha$. Elastic and inelastic scattering of ${}^6$Li on ${}^{12}$C are analyzed using both the Optical Model and Coupled channels approaches, with the interaction described by a double-folding potential. This potential is calculated based on the three-body wave function of ${}^6$Li. Pronounced coupled-channel effects are observed, which modify the potential and allow accurate reproduction of the experimental cross sections. The resulting polarized potentials provide a more precise description of the initial-state interaction for further reaction modelling. The deuteron transfer channel, ${}^{12}$C(${}^6$Li, $\alpha$)${}^{14}$N, is studied using the Coupled Reaction Channels method. The coupling between the transfer and elastic channels is implemented using the three-body wave function of ${}^6$Li. As an alternative, a regular wave function constructed with a phenomenological Woods-Saxon potential is also employed. Comparison between the calculated differential cross sections and experimental data reveals a more complex and nuanced reaction mechanism, which supports the cluster structure of ${}^6$Li.

   nucl-exnucl-thCPC(2026)·2 citations
8. 08*

   Collective effects in O-O and Ne-Ne collisions at $\sqrt{s_{\mathrm{NN}}}$=5.36 TeV from a hybrid approach

   Lucas Constantin🇩🇪 · Niklas Götz🇩🇪 · Carl B. Rosenkvist🇩🇪 · Hannah Elfner🇩🇪

   Many features of heavy-ion collisions are well described by hybrid approaches, where the droplet of strongly coupled quark gluon plasma (QGP) is modeled by hydrodynamics and the subsequent dilute stage is performed with a hadronic transport model. Conventionally, the formation of a QGP is well established in larger collision systems like lead and gold. However, hints of collectivity were found even in proton-proton collisions, raising the question where the onset of QGP formation lays. This study aims at making predictions for the light-ions run at the CERN Large Hadron Collider in July 2025, in order to explore the applicability of hybrid approaches in smaller collision systems. We employ three different models: the SMASH-vHLLE hybrid approach, the pure hadronic cascade of SMASH, and Angantyr to simulate O-O collisions at a center-of-mass energy of $\sqrt{s_{\mathrm{NN}}}$=5.36 TeV. This setup allows us to compare evolutions with and without a hydrodynamic description on an equal basis, while Angantyr serves as a baseline for no collective effects.

   ↳ nucl-thnucl-exPRC(2026)·5 citations
9. 09*

   Longitudinal Spin Transfer to $\Lambda$ Hyperons in Semi-Inclusive Deep Inelastic Scattering with CLAS12

   M. McEneaney · A. Vossen (for the CLAS Collaboration)

   The polarization of $\Lambda$ hyperons is preserved in the angular distribution of their decay products. This property allows one to study the spin structure of the $\Lambda$. In Semi-Inclusive Deep Inelastic Scattering where a high energy lepton interacts with a nucleon target and one or more hadrons and the scattered lepton are detected in the final state, the probability for a struck quark to impart the polarization of the lepton to the $\Lambda$ may be measured. In particular, in electron-proton scattering this quantity may be related to the longitudinal light quark polarization of the $\Lambda$. Currently, limited experimental data cannot discriminate between different models of $\Lambda$ spin structure. This work reports on the measurement of the longitudinal spin transfer $D_{L{L}^{\prime }}^{\Lambda }$ to the $\Lambda$ using data taken by the CLAS12 spectrometer at Jefferson Lab with a $10.6$ GeV longitudinally polarized electron beam and an unpolarized hydrogen target. This measurement is the most precise to date, and, in comparison with theory predictions, it offers valuable insight into the relative dominance of current and target fragmentation in $\Lambda$ production.

   ↳ hep-exnucl-exPRD(2026)·2 citations
10. 10*

    Upgrades of the ATLAS Zero Degree Calorimeter System for Run 3 at the Large Hadron Collider

    Giulio Avoni🇮🇹 · Marco Bruschi🇮🇹 · Gianluca Canale🇨🇭 · Zvi Citron🇮🇱 · Brian Cole🇺🇸 · Eitan Dahle🇺🇸 · Bartosz Dziedzic🇨🇭 · Bar Glik🇮🇱 · Matthias Grosse-Perdekamp🇺🇸 · Yhan Guo🇺🇸 · Krzysztof Korcy🇵🇱 · Matthew Hoppesch🇺🇸 and 20 other authors

    Experimental studies of ultra-relativistic heavy ion collisions at the Large Hadron Collider (LHC) depend crucially on Zero Degree Calorimeters (ZDCs) that measure neutrons produced at near-beam rapidity in nucleus-nucleus collisions. In hadronic nuclear collisions these neutrons are mainly spectator neutrons, those that do not scatter from opposing nucleons during the collision. As a result, the ZDCs provide a vital probe of heavy ion collision geometry. The ZDCs are also essential in the study of ultra-peripheral collisions that are initiated by photons associated with the electric fields of one or both nuclei. Coherent photon emission typically leaves the photon emitter intact, making the observation of no ZDC signal, on one or both sides, a tag of such processes. The ATLAS ZDCs, built prior to Run 1 were substantially upgraded for LHC Run 3. The primary upgrades included replacement of the quartz Cherenkov radiator with ${\text{H}}_2$-doped fused silica rods; installation of fast air-core signal cables between the ZDC and the ATLAS USA15 cavern; new LED-based calibration system; and new electronics implemented for readout and fully-digital triggering. The ZDCs were also augmented with new "Reaction Plane Detectors" (RPDs) designed to measure the transverse centroid of multi-neutron showers to allow event-by-event reconstruction of the directed-flow plane in nuclear collisions. The Run~3 ZDC detectors, including the RPDs, are described in detail with emphasis on aspects that are new for Run~3.

    ↳ physics.ins-dethep-exnucl-exJINST(2025)·12 citations
11. 11*

    Ab initio calculations of beta-decay half-lives for $N=50$ neutron-rich nuclei

    Zhen Li🇩🇪 · Takayuki Miyagi🇩🇪 · Achim Schwenk🇩🇪

    Beta-decay rates of extreme neutron-rich nuclei remain largely unknown experimentally, while they are critical inputs for $r$-process nucleosynthesis. We present first ab initio calculations of total beta-decay half-lives, with a focus on $N=50$ nuclei. Starting from nuclear forces and currents based on chiral effective field theory, we use the in-medium similarity renormalization group to consistently derive valence-space Hamiltonians and weak operators, from which we calculate the nuclear states involved and the Gamow-Teller transition strengths, without phenomenological adjustments. In addition, we explore effects of first-forbidden contributions. Our results show that the inclusion of two-body currents increases the total half-lives, which then show good agreement with the existing experimental data, thereby validating the predictive capability of our approach.

    ↳ nucl-thastro-ph.HEnucl-exPRL(2026)·14 citations
12. 12*

    Energy loss baseline for light hadrons in oxygen-oxygen collisions at $\sqrt{s_{\mathrm{NN}}}=5.36\text{TeV}$

    Aleksas Mazeliauskas🇩🇪

    I present predictions for inclusive charged hadron spectra in minimum-bias proton-proton and oxygen-oxygen collisions at a centre-of-mass energy of $\sqrt{s_{\mathrm{NN}}}=5.36\text{TeV}$, assuming no final-state interactions. Using next-to-leading order perturbative QCD matrix elements, along with state-of-the-art (nuclear) parton distribution and fragmentation functions, I establish a baseline for the nuclear modification factor $R_{\text{AA}}^h$ in oxygen-oxygen collisions in the absence of quenching. Theoretical uncertainties in this baseline are found to be substantial for transverse momenta below $20\text{GeV}$. In the intermediate range $20\text{GeV}\lesssim p_T^h\lesssim 70\text{GeV}$, these uncertainties are significantly reduced to approximately 5\%. At higher momenta ($p_T^h\gtrsim 70\text{GeV}$), however, predictions exhibit a marked spread due to differences between fragmentation functions, reflecting varying assumptions about isospin symmetry. Finally, I show that considering neon-neon collisions in the initial state or neutral pions in the final state does not appreciably change the nuclear modification factor.

    ↳ hep-phnucl-exnucl-thPLB(2026)·10 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.