Mon·Jul 28, 2025Monday·July 28, 2025

1. 01*

   Overview of recent results from the STAR experiment

   Isaac Mooney (for the STAR Collaboration)🇺🇸

   We highlight the STAR experiment's recent measurements on electromagnetic and hard probes of nuclear collisions, which inform the field's understanding of these physical phenomena and by extension QCD. Results on vector meson production from the high electromagnetic fields in glancing heavy-ion collisions are presented. Observables related to jets, high-momentum hadrons, heavy quarks and quarkonia in vacuum and their modification in head-on heavy-ion collisions are also presented. Studies using electromagnetic probes of the medium created in these collisions are presented as well. Finally, we conclude and give an outlook for STAR data-taking and measurements in the coming years.

   nucl-exEPJ Web Conf.(2025)·0 citations
2. 02*

   Velocity dependence of the mass modifications of $\rho$ and $\omega$ mesons in 12 GeV $p+A$ reactions

   Wataru Nakai🇯🇵 · Kazuya Aoki🇯🇵 · Junsei Chiba🇯🇵 · Hideto En'yo🇯🇵 · Yoshinori Fukao🇯🇵 · Haruhiko Funahashi🇯🇵 · Hideki Hamagaki🇯🇵 · Masaharu Ieiri🇯🇵 · Masaya Ishino🇯🇵 · Hiroki Kanda🇯🇵 · Koki Kanno🇯🇵 · Masaaki Kitaguchi🇯🇵 and 17 other authors

   This study measured the invariant mass spectra of $\rho$ and $\omega$ mesons in the $e^{+}{e}^{-}$ decay channel for 12 GeV (12.9 GeV/$c$) $p+\mathrm{C}$ and $p+\mathrm{Cu}$ reactions (${\sqrt{s}}_{NN}=5.1$ GeV) at the KEK 12-GeV Proton Synchrotron. The measured spectra were divided into three $\beta \gamma$ regions to examine their velocity dependence. Across all regions, significant excesses were observed on the low-mass side of the $\omega$ meson peak, beyond the contributions of known hadronic sources, in the data of the C and Cu targets. Model calculations were subsequently performed to evaluate the magnitudes of the mass modifications of $\rho$ and $\omega$ mesons.

   nucl-exPTEP(2025)·0 citations
3. 03*

   Multiplicity dependence of K${}^{\ast }(892{)}^{\pm }$ production in pp collisions at $\sqrt{s}$ = 13 TeV

   ALICE Collaboration

   The first results of K${}^{\ast }$(892)${}^{\pm }$ production at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}=13$ TeV as a function of the event multiplicity are presented. The K${}^{\ast }$(892)${}^{\pm }$ has been reconstructed via its hadronic decay channel K${}^{\ast }$(892)${}^{\pm }\to {\pi }^{\pm }+K_{\mathrm{S}}^0$ using the ALICE detector at the LHC. For each multiplicity class the differential transverse momentum ($p_{\mathrm{T}}$) spectrum, the mean transverse momentum $⟨p_{\mathrm{T}}⟩$, the $p_{\mathrm{T}}$-integrated yield (d$N$/d$y$), and the ratio of the K${}^{\ast }$(892)${}^{\pm }$ to $K_{\mathrm{S}}^0$ yields are reported. These are consistent with previous K${}^{\ast }$(892)${}^0$ resonance results with a higher level of precision. Comparisons with phenomenological models such as PYTHIA6, PYTHIA8, EPOS-LHC, and DIPSY are also discussed. A first evidence of a significant K${}^{\ast }$(892)${}^{\pm }$/$K_{\mathrm{S}}^0$ suppression in pp collisions is observed at a 7$\sigma$ level passing from low to high multiplicity events. The ratios of the $p_{\mathrm{T}}$-differential yields of K${}^{\ast }$(892)${}^{\pm }$ and $K_{\mathrm{S}}^0$ in high and low multiplicity events are also presented along with their double ratio. For $p_{\mathrm{T}}\lesssim 2$ GeV/$c$ this double ratio persists below unity by more than $3\sigma$ suggesting that the suppression affects mainly low $p_{\mathrm{T}}$ resonances. The measured decreasing trend of the K${}^{\ast }$(892)${}^{\pm }$/$K_{\mathrm{S}}^0$ ratio with increasing multiplicity, which in heavy-ion collisions is typically attributed to the rescattering of decay particles of the short-lived resonances, is reproduced by the EPOS-LHC model without the use of hadronic afterburners.

   nucl-exhep-exPLB(2026)·0 citations
4. 04*

   Multiplicity dependence of f${}_0$(980) production in pp collisions at $\sqrt{s}=13$ TeV

   ALICE Collaboration

   The dependence of ${\mathrm{f}}_0$(980) production on the final-state charged-particle multiplicity is reported for proton-proton (pp) collisions at the centre-of-mass energy, $\sqrt{s}=13$ TeV. The production of ${\mathrm{f}}_0$(980) is measured with the ALICE detector via the ${\mathrm{f}}_0(980)\to {\pi }^{+}{\pi }^{-}$ decay channel in a midrapidity region of $|y|<0.5$. The evolution of the integrated yields and mean transverse momentum of f${}_0$(980) as a function of charged-particle multiplicity measured in pp at $\sqrt{s}=13$ TeV follows the trends observed in pp at $\sqrt{s}=5.02$ TeV and in proton-lead (p-Pb) collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. Particle yield ratios of ${\mathrm{f}}_0$(980) to ${\pi }^{\pm }$ and ${\mathrm{K}}^{\ast }$(892)${}^0$ are found to decrease with increasing charged-particle multiplicity. These particle ratios are compared with calculations from the canonical statistical thermal model as a function of charged-particle multiplicity. The thermal model calculations provide a better description of the decreasing trend of particle ratios when no strange or antistrange quark composition for f${}_0$(980) is assumed, which suggests that the data do not support significant hidden strangeness in the f${}_0$(980).

   nucl-exhep-exEPJC(2026)·4 citations
5. 05*

   ${\mathrm{K}}_1(1270)$ production in pp collisions with ALICE

   Su-Jeong Ji (for the ALICE Collaboration)🇰🇷

   The study of chiral partners such as ${\mathrm{K}}_1$ and ${\mathrm{K}}^{\ast }$ mesons, which have vacuum widths below 100 MeV, provides an opportunity to explore chiral symmetry restoration in heavy-ion collisions. A recent theoretical model suggests that the ${\mathrm{K}}_1/{\mathrm{K}}^{\ast }$ ratio in heavy-ion collisions should be significantly larger than that predicted by the statistical hadronisation model. Investigating the ${\mathrm{K}}_1/{\mathrm{K}}^{\ast }$ ratio as a function of multiplicity across various collision systems, from pp to central heavy-ion collisions, can shed light on the impact of chiral symmetry restoration. However, the ${\mathrm{K}}_1$ meson has yet to be observed in hadron-hadron collisions. The ALICE detector's advanced particle identification capabilities enable the measurement of the ${\mathrm{K}}_1$ meson through hadronic decay modes, such as ${\mathrm{K}}_1^{-}\to {\rho }^0{\mathrm{K}}^{-}$ and ${\mathrm{K}}_1^{-}\to {\pi }^{-}{\bar{\mathrm{K}}}^{\ast 0}$. This presentation discusses the feasibility of measuring ${\mathrm{K}}_1$ mesons in pp collisions using the ALICE experiment.

   nucl-exJ.Subatomic Part.Cosmol.(2025)·0 citations
6. 06*

   Particle Correlations in Jets

   Wenbin Zhao🇺🇸 · Volker Koch🇺🇸 · Feng Yuan🇺🇸

   We study particle correlations in high energy jets by comparing the measured energy-energy correlator (EEC) with that constructed from two individual energy flows with respect to the jet axis. This comparison demonstrates that genuine correlations exists for small angle and moderate/large angle, indicating that they are coming from correlated splitting. This method will provide a unique tool to disentangle different physics, by comparing the genuine correlations in jet EEC between heavy ion collisions and proton-proton collisions. It will help to expose the medium modification of parton splitting in hot QCD medium. On the other hand, the medium responses are expected to be canceled out in the genuine correlations.

   ↳ hep-phnucl-exnucl-th8 citations
7. 07*

   Classification of flavor dependence of Chiral Magnetic Effect with Deep Neural Network using multiple correlators

   Somdeep Dey🇮🇳 · Abhisek Saha🇨🇳 · Soma Sanyal🇮🇳

   We study the flavor dependence of the Chiral Magnetic Effect (CME) by analyzing two key charge-separation correlators used to characterize the charge separation effect: the conventional $\Delta \gamma$ and the recently proposed $R_{{\psi }_2}$. Using the AMPT (A Multiphase Transport) model with an initial-state centrality-dependent charge separation, we evaluate the sensitivity of these correlators to 2-flavor ($u,d$) and 3-flavor ($u,d,s$) quark scenarios. While both correlators exhibit modest flavor dependence in mid-central (30-50\%) collisions, their discriminative power varies significantly with centrality and transverse momentum ($p_T$), limiting their utility disentangling the flavor dependent scenarios. To overcome these limitations, we develop a neural network classifier trained on final-state hadronic observables (e.g., $d{N}_{ch}/d\eta$, $p_T$ spectra). The model achieves $>90\%$ accuracy in flavor classification by leveraging multi-observable correlations, with $p_T$-differential features proving particularly discriminative. Crucially, by incorporating background contributions directly into the training data, our approach provides more reliable flavor estimates than correlator-only methods.

   ↳ nucl-thhep-phnucl-exPRC(2026)·2 citations
8. 08*

   Adressing the p{\Omega}- interaction and di-baryonic states via femtoscopy

   Marta Piscitelli · Otón Vázquez Doce🇮🇹

   Motivated by recent experimental measurements of the p${\Omega }^{-}$ correlation function and the concurrent theoretical efforts to describe the strong interaction among hadrons in the strangeness sector, we present a data-driven approach for fine tuning of a meson-exchanges potential for the p${\Omega }^{-}$ system. Using femtoscopy data from the ALICE and STAR collaborations, we constrain the strength of the interaction, encoded in the tunable short-range parameter introduced in the potential. The resulting model provides a good description of the measured correlation functions and favors the existence of a bound state in the \({}^5S_2\) channel with a binding energy of approximately \(0.5\,\mathrm{MeV}\). The role of the \({}^3S_1\) channel, however, remains poorly constrained due to the absence of an accurate model accounting for its inelastic contributions.

   ↳ nucl-thnucl-exPoS(2026)·1 citation
9. 09*

   Machine Learning Based Efficiency Calculator (MaLBEC) for Nuclear Fusion Diagnostics

   Kimberley Lennon · Chantal Shand · Gemma Wilson🇺🇸 · Robin Smith🇬🇧

   Diagnostics are critical for commercial and research fusion machines, since measuring and understanding plasma features is important to sustaining fusion reactions. The neutron flux (and therefore fusion power) can be indirectly calculated using neutron activation analyses, where potentially large numbers of activation foils are placed in the neutron flux, and delayed gammas from key reactions are measured via gamma spectrometry. In gamma spectrometry, absolute efficiency forms part of the activity calculation, and equals to the ratio of the total number of photons detected to the number emitted by a radioactive sample. Hence, it is imperative that they are calculated efficiently and accurately. This paper presents a novel digital efficiency calculation algorithm, the Machine Learning Based Efficiency Calculator (MaLBEC), that uses state-of-the-art supervised machine learning techniques to calculate efficiency values of a given sample, from only four inputs. In this paper, the performance of the MaLBEC is demonstrated with a fusion sample and compares the values to a traditional efficiency calculation method, Monte Carlo N-Particle (MCNP). The efficiencies from the MaLBEC were within an average 5\% of the ones produced by MCNP, but with an exceptional reduction in computation time of 99.96\%. When the efficiency values from both methods were used in the activity calculation, the MaLBEC was within 3\% of the MCNP results.

   ↳ physics.ins-detnucl-ex0 citations
10. 10*

    Modeling direct and pre-equilibrium processes of neutron-induced reactions with noniterative finite amplitude method and distorted-wave Born approximation

    Hirokazu Sasaki🇺🇸 · Toshihiko Kawano🇺🇸 · Marc Dupuis🇫🇷

    We develop a calculation method for describing the direct and pre-equilibrium processes in neutron-induced reactions based on the framework of noniterative finite amplitude method (FAM) and distorted-wave Born approximation (DWBA). The noniterative FAM is used to derive equations of quasiparticle random-phase approximation (QRPA) for neutron-induced inelastic scatterings to both the discrete and continuum states in a consistent manner. The Skyrme force is employed as an interaction between the projectile neutron with nucleons inside the target nucleus. We apply this method to the neutron-induced reaction on 208Pb. We demonstrate that the calculated differential inelastic scattering cross sections to low-lying states reproduce available experimental data without any phenomenological parameters that are often introduced in conventional DWBA calculations. The calculated double differential cross section to the continuum state also agrees with the experimental data in the energy region relevant to the direct and pre-equilibrium processes. These results are used to investigate the spin distribution of the populated states in the residual nucleus.

    ↳ nucl-thastro-ph.HEnucl-exPRC(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.