Tue·Sep 17, 2024Tuesday·September 17, 2024

1. 01*

   Imaging the structure of atomic nuclei in high-energy nuclear collisions from STAR experiment

   Chunjian Zhang (for the STAR Collaboration)🇨🇳

   In relativistic heavy-ion collisions, the extractions of properties of quark-gluon plasma (QGP) are hindered by a limited understanding of its initial conditions, where the nuclear structure of the colliding ions play a significant role. In these proceedings, we present the first quantitative demonstration using ``collective flow assisted nuclear shape imaging" method to extract the quadrupole deformation and triaxiality from ${}^{238}$U using data from the Relativistic Heavy Ion Collider (RHIC). We achieve this by comparing bulk observables in ${}^{238}$U+${}^{238}$U collisions with nearly spherical ${}^{197}$Au+${}^{197}$Au collisions. A similar comparative measurement performed in collisions of ${}^{96}$Ru+${}^{96}$Ru and ${}^{96}$Zr+${}^{96}$Zr, suggests the presence of moderate quadrupole deformation of ${}^{96}$Ru, large octupole deformation of ${}^{96}$Zr, as well as an apparent neutron skin difference between these two species. The prospect of this nuclear shape imaging method as a novel tool for the study of nuclear structure is also elaborated.

   nucl-exhep-exNPA(2025)·2 citations
2. 02*

   N${}^3$LL + $\mathcal{O}({\alpha }_s^2)$ predictions of lepton-jet azimuthal angular distribution in deep-inelastic scattering

   Shen Fang🇨🇳 · Mei-Sen Gao🇨🇳 · Hai Tao Li🇨🇳 · Ding Yu Shao🇨🇳

   We present an analysis of lepton-jet azimuthal decorrelation in deep-inelastic scattering (DIS) at next-to-next-to-next-to-leading logarithmic (N${}^3$LL) accuracy, combined with fixed-order corrections at $\mathcal{O}({\alpha }_s^2)$. In this study, jets are defined in the lab frame using the anti-$k_T$ clustering algorithm and the winner-take-all recombination scheme. The N${}^3$LL resummation results are derived from the transverse-momentum dependent factorization formula within the soft-collinear effective theory, while the $\mathcal{O}({\alpha }_s^2)$ fixed-order matching distribution is calculated using the {\tt NLOJET++} event generator. The azimuthal decorrelation between the jet and electron serves as a critical probe of the three-dimensional structure of the nucleon. Our numerical predictions provide a robust framework for precision studies of QCD and the nucleon's internal structure through jet observables in DIS. These results are particularly significant for analyses involving jets in HERA data and the forthcoming electron-ion collider experiments.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2025)·11 citations
3. 03*

   Multiple-models prediction for light neutron-rich isotopes cross section by $Q_g$ systematics in ${}^{40}$Ar projectile fragmentation reactions

   X. B. Wei · H. L. Wei🇨🇳 · C. W. Ma · C. Y. Qiao · Y. F. Guo🇨🇳 · J. Pu🇨🇳 · K. X. Cheng🇹🇼 · Y. T. Wang · Z. X. Wang🇨🇳 · T. R. Zhou · D. Peng🇬🇧 · S. T. Wang🇨🇳 and 11 other authors

   Precise predictions for nuclei near drip lines are crucial for experiments in new generation of rare isotope facilities. A multi-models investigation of the $Q_g$ systematics for fragments production cross sections, with $Q_g$ defined as the difference of mass excess (ME) between the projectile ($Z_p,A_p$) and the fragment ($Z_f,A_f$) nuclei $Q_g=ME(Z_p,A_p)-ME(Z_f,A_f)$, has been performed to verify the model prediction abilities for light neutron-rich isotopes in measured ${}^{40}$Ar + ${}^9$Be projectile fragmentation reactions from 57$A$ MeV to 1$A$ GeV. The models used are the FRACS parametrizations and the newly developed Bayesian neural networks (BNN) model. %method The results show that FRACS, BNN, and $Q_g$ extrapolations are generally consistent, except for fragments near the nuclear mass of the projectile. Additionally, both measured data and model extrapolations provide evidence for a shell closure at $N=$ 16 in fluorine and neon, as well as the disappearance of the traditional magic number $N=$ 20 in neon, sodium and magnesium.

   ↳ nucl-thnucl-ex0 citations
4. 04*

   Pion-nucleon scattering with decuplet contribution in heavy baryon SU(3) chiral perturbation theory

   Jing Ou-Yang🇨🇳 · Bo-Lin Huang🇨🇳

   We calculate the complete $T$ matrices with decuplet contributions for pion-nucleon scattering to order $\mathcal{O}({ϵ}^3)$ in heavy baryon SU(3) chiral perturbation theory. The baryon mass in the chiral limit $M_0$ and the low-energy constants are determined by fitting to phase shifts of $\pi N$, the experimental octet-baryon masses, and the value of ${\sigma }_{\pi N}$ simultaneously. By using these constants, we obtain the $KN$ $\sigma$ terms, ${\sigma }_{KN}^{(1)}=(375.07\pm 33.02)$ MeV and ${\sigma }_{KN}^{(2)}=(275.32\pm 32.24)$ MeV, with the errors being only statistical. An excellent description of the phase shifts is obtained for all partial waves. We also present results for scattering lengths and scattering volumes. In addition, the convergence of the approach is also discussed.

   ↳ nucl-thhep-lathep-phnucl-exPRD(2024)·4 citations
5. 05*

   Fuzzy logic for reconstructing arbitrary moments of multiplicity distributions

   Anar Rustamov🇩🇪

   The Identity Method is a statistical technique developed to reconstruct moments of multiplicity distributions of particles produced in high-energy nuclear collisions. The method leverages principles from fuzzy logic, allowing for a more nuanced representation of particle identification by assigning degrees of membership to different particle types based on detector signals. In this contribution, a new framework, based on a multivariate moment generation function, is developed that allows the derivation of the formulas used in the Identity Method in a more robust way. Moreover, within the introduced framework, the Identity Method is easily extended to cope with arbitrarily higher-order moments. The techniques developed here offer significant potential for improving the accuracy of multiplicity distribution analyses in high-energy nuclear collisions. While the primary focus of the work presented is on applications in high-energy particle and nuclear physics, it can also be applied in other areas where signal identification is probabilistic and data are noisy, such as in medical imaging, remote sensing, and various other fields of experimental science.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2024)·5 citations
6. 06*

   The Current State of the Controversy over Screening in Nuclear Reactions

   Werner Däppen

   A controversy about the possibility of dynamic effects in nuclear screening has been around for several decades. On the one hand, there is the claim that there are no dynamic effects, and that the classic Salpeter correction based on static Debye screening is all that is needed for astrophysical applications. The size of the correction is on the order of 5% in typical solar fusion reactions. On the other hand, numerical simulations have shown that there is a dynamical effect, which essentially cancels the Salpeter correction. The results of the numerical simulations were later independently confirmed. The astrophysical community, however, has so far largely ignored the possibility of dynamical screening. The present paper is meant to serve as a reminder of the controversy. Not only does the claim of an absence of a dynamical effect equally warrant an independent confirmation, but there is motivation for further investigation, such as the assessment of current laboratory experiments and a quantitative study of the dynamical effect in case it will turn out to be real.

   ↳ astro-ph.SRnucl-exnucl-thSolar Phys.(2024)·1 citation
7. 07*

   Multiple rescattering effects in the hard knockout reaction ${}^2\text{mbox}\mathbf{H}(\mathbf{p},2p)\mathbf{n}$

   A.B. Larionov🇷🇺

   The interaction of a proton with a deuteron is the simplest nuclear reaction. However, it allows the study of precursors of nuclear medium effects such as initial-state/final-state interactions (ISI/FSI). In case of hard proton knockout, the deviation of ISI/FSI from the 'standard' values may carry a signal of color transparency. In this regard, it is important to define the 'standard' as precisely as possible. This work continues previous studies within the framework of the Generalized Eikonal Approximation (GEA). The focus is on processes where the participating protons experience multiple soft rescattering on the spectator neutron. It is shown that correct treatment of deviations of the trajectories of outgoing protons from the longitudinal direction leads to a significant modification of partial amplitudes with soft rescattering of two outgoing protons and non-vanishing amplitudes with rescattering of incoming and outgoing protons. The new treatment of multiple rescattering is important in kinematics with a forward spectator neutron.

   ↳ nucl-thhep-exhep-phnucl-exEPJA(2025)·1 citation
8. 08*

   Ab initio calculations of anomalous seniority breaking in the $\pi g_{9/2}$ shell for the $N=50$ isotones

   Q. Yuan🇨🇳 · B. S. Hu🇨🇦

   We performed \textit{ab initio} valence-space in-medium similarity renormalization group (VS-IMSRG) calculations based on chiral two-nucleon and three-nucleon interactions to investigate the anomalous seniority breaking in the neutron number $N=50$ isotones: ${}^{92}$Mo, ${}^{94}$Ru, ${}^{96}$Pd, and ${}^{98}$Cd. Our calculations well reproduced the measured low-lying spectra and electromagnetic $E2$ transitions in these nuclei, supporting partial seniority conservation in the first $\pi g_{9/2}$ shell. Recent experiments have revealed that, compared to the symmetric patterns predicted under the conserved seniority symmetry, the $4_1^{+}\to 2_1^{+}$ $E2$ transition strength in ${}^{94}$Ru is significantly enhanced and that in ${}^{96}$Pd is suppressed. In contrast, the $6_1^{+}\to 4_1^{+}$ and $8_1^{+}\to 6_1^{+}$ transitions exhibit the opposite trend. We found that this anomalous asymmetry is sensitive to subtle seniority breaking effects, providing a stringent test for state-of-the-art nucleon-nucleon interactions and nuclear models. We analyzed the anomalous asymmetry using VS-IMSRG calculations across various valence spaces. Our \textit{ab initio} results suggest that core excitations of both proton and neutron across the $Z=50$ shell are ascribed to the observed anomalous seniority breaking in the $N=50$ isotones.

   ↳ nucl-thnucl-exPLB(2024)·9 citations
9. 09*

   Neutron Tagging Can Greatly Reduce Spallation Backgrounds in Super-Kamiokande

   Obada Nairat🇺🇸 · John F. Beacom🇺🇸 · Shirley Weishi Li🇺🇸

   Super-Kamiokande's spallation backgrounds - the delayed beta decays of nuclides following cosmic-ray muons - are nearly all produced by the small fraction of muons with hadronic showers. We show that these hadronic showers also produce neutrons; their captures can be detected with high efficiency due to the recent addition of dissolved gadolinium to Super-Kamiokande. We show that new cuts based on the neutron tagging of showers could reduce spallation backgrounds by a factor of at least four beyond present cuts. With further work, this could lead to a near-elimination of detector backgrounds above about 6 MeV, which would significantly improve the sensitivity of Super-Kamiokande. These findings heighten the importance of adding gadolinium to Hyper-Kamiokande, which is at a shallower depth. Further, a similar approach could be used in other detectors, for example, the JUNO liquid-scintillator detector, which is also at a shallower depth.

   ↳ hep-phastro-ph.HEhep-exnucl-ex+1PRD(2025)·13 citations
10. 10*

    The ALICE 3 detector concept for LHC Runs 5 and 6 and its physics performance

    Robert Vertesi (for the ALICE Collaboration)🇭🇺

    The LHC Run 5 and 6 data taking phases will bring unprecedented luminosity in high-energy proton-proton and in heavy-ion collisions. The ALICE Collaboration proposes a next-generation experiment, ALICE 3, specifically designed to operate with the future LHC. ALICE 3 will feature a large pixel-based tracking system covering eight units of pseudorapidity, complemented by advanced particle identification systems. These include silicon time-of-flight layers, a ring-imaging Cherenkov detector, a muon identification system, and an electromagnetic calorimeter. By placing the vertex detector on a retractable plate inside the beam pipe, a track pointing resolution better than 10 microns can be achieved for the transverse momentum range $p_T$>200 MeV/c. ALICE 3 will be capable of innovative measurements of the quark-gluon plasma (QGP) and explore new frontiers in quantum chromodynamics (QCD). The detailed study of thermal and dynamical properties of QGP will be made possible by measuring low-$p_T$ heavy-flavour production, including beauty hadrons, multi-charm baryons, and charm-charm correlations. Precise multi-differential measurements of dielectron emission will allow for the exploration of chiral-symmetry restoration and the time-evolution of QGP temperature. In addition to QGP studies, ALICE 3 will make unique contributions to the physics of the hadronic phase, through femtoscopic studies of charm meson interaction potentials and searches for nuclei containing charm. This contribution covers the detector design, expected physics performance, and the current status of detector research and development.

    ↳ physics.ins-detnucl-exEur.Phys.J.ST(2025)·2 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.