Tue·Oct 14, 2025Tuesday·October 14, 2025

1. 01*

   Observation of suppressed charged-particle production in ultrarelativistic oxygen-oxygen collisions

   CMS Collaboration

   A hot and dense state of nuclear matter, known as the quark-gluon plasma, is created in collisions of ultrarelativistic heavy nuclei. Highly energetic quarks and gluons, collectively referred to as partons, lose energy as they travel through this matter, leading to suppressed production of particles with large transverse momenta ($p_{\mathrm{T}}$). Conversely, high-$p_{\mathrm{T}}$ particle suppression has not been seen in proton-lead collisions, raising questions regarding the minimum system size required to observe parton energy loss. Oxygen-oxygen (OO) collisions examine a region of effective system size that lies between these two extreme cases. The CMS detector at the CERN LHC has been used to quantify charged-particle production in inclusive OO collisions for the first time via measurements of the nuclear modification factor ($R_{\mathrm{AA}}$). The $R_{\mathrm{AA}}$ is derived by comparing particle production to expectations based on proton-proton (pp) data and has a value of unity in the absence of nuclear effects. The data for OO and pp collisions at a nucleon-nucleon center-of-mass energy $\sqrt{s_{\mathrm{NN}}}$ = 5.36 TeV correspond to integrated luminosities of 6.1 nb${}^{-1}$ and 1.02 pb${}^{-1}$, respectively. The $R_{\mathrm{AA}}$ is below unity with a minimum of 0.69 $\pm$ 0.04 around $p_{\mathrm{T}}$ = 6 GeV. The data exhibit better agreement with theoretical models incorporating parton energy loss as compared to baseline models without energy loss.

   nucl-exhep-exPRL(2026)·49 citations
2. 02*

   Realizing the Scientific Program with Polarized Ion Beams at EIC

   Grigor Atoian🇺🇸 · Nigel Buttimore🇮🇪 · Giuseppe Ciullo🇮🇹 · Ian Cloet🇺🇸 · Marco Contalbrigo🇮🇹 · Jaydeep Datta🇺🇸 · Abhay Deshpande🇺🇸 · Shubham Dutta🇮🇳 · Oleg Eyser🇺🇸 · Muhammad Farooq🇺🇸 · Renee Fatemi🇺🇸 · Ishara Fernando🇺🇸 and 58 other authors

   Polarized ion beams at the Electron Ion Collider are essential to address some of the most important open questions at the twenty-first century frontiers of understanding of the fundamental structure of matter. Here, we summarize the science case and identify polarized ${}^2$H, ${}^3$He, ${}^6$Li and ${}^7$Li ion beams as critical technology that will enable experiments which address the most important science. Further, we discuss the required ion polarimetry and spin manipulation in EIC. The current EIC accelerator design is presented. We identify a significant R\&D effort involving both national laboratories and universities that is required over about a decade to realize the polarized ion beams and estimate (based on previous experience) that it will require about 20 FTE over 10 years (or a total of about 200 FTE-years) of personnel, including graduate students, postdoctoral researchers, technicians and engineers. Attracting, educating and training a new generation of physicists in experimental spin techniques will be essential for successful realization. AI/ML is seen as having significant potential for both acceleration of R\&D and amplification of discovery in optimal realization of this unique quantum technology on a cutting-edge collider. The R\&D effort is synergistic with research in atomic physics and fusion energy science.

   nucl-exnucl-thphysics.acc-phphysics.ins-detPRC(2026)·7 citations
3. 03*

   Higher-Order Fluctuations: Unveiling the Final Frontier of QCD at the LHC with ALICE

   Ilya Fokin (for the ALICE Collaboration)🇩🇪

   Lattice QCD (LQCD) calculations predict that chiral symmetry is restored in a smooth crossover transition between a quark-gluon plasma and a hadron resonance gas (HRG) at vanishing net-baryon density, a condition realized in heavy-ion collisions at the LHC. In this regime, the net-baryon number cumulants computed using the HRG and LQCD partition functions are in good agreement up to third order. However, starting with the fourth-order cumulants, the LQCD results are significantly lower than the corresponding HRG results. This offers a unique opportunity to experimentally verify the full QCD partition function by measuring the fourth-order cumulants of the net-proton number distributions. We present net-proton number cumulants up to sixth order in proton-proton collisions at top LHC energy recorded by ALICE to search for effects of a possible chiral phase transition in this small system. An extension of the net-proton measurements in Pb-Pb collisions to fourth order is also presented. In addition to providing experimental access to the full QCD partition function, these measurements will, for the first time, allow to distinguish between different mechanisms of baryon production.

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

   Investigating subnucleonic structures via new measurements of incoherent J/$\psi$ photoproduction in ultra-peripheral Pb--Pb collisions with ALICE

   Vendulka Humlová (on behalf of the ALICE Collaboration)🇨🇿

   Ultra-peripheral collisions of heavy ions provide a unique environment to study the gluon structure of nuclei through photon-induced reactions. In particular, the incoherent photoproduction of J/$\psi$ vector meson is sensitive to event-by-event fluctuations of the gluon field at nucleon and subnucleonic scales. We report new ALICE measurement of incoherent J/$\psi$ production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV, differential in both photon-nucleus energy and Mandelstam-$|t|$. At low $|t|$, the cross section rises with increasing photon-nucleus energy, while at larger $|t|$ the growth is suppressed with respect to the trend at low $|t|$. This measurement represents the first study of incoherent photoproduction at the LHC performed as a function of both $W_{\gamma \mathrm{Pb},n}$ and $|t|$.

   nucl-exhep-exEPJ Web Conf.(2026)·0 citations
5. 05*

   Triaxiality and shape dynamics in ${}^{70}$Ge

   T. M. Kowalewski · A. D. Ayangeakaa🇺🇸 · N. Sensharma🇺🇸 · R. V. F. Janssens🇺🇸 · Y. M. Wang · Q. B. Chen🇨🇳 · J. M. Allmond🇺🇸 · C. M. Campbell · S. Carmichael · M. P. Carpenter🇺🇸 · P. Copp · C. Cousins and 22 other authors

   The electromagnetic properties of low-lying states in ${}^{70}$Ge were investigated via multi-step Coulomb excitation of a ${}^{70}$Ge beam impinging on a ${}^{208}$Pb target at the ATLAS facility of the Argonne National Laboratory. A total of 27 transitional elements and six diagonal matrix elements coupling 11 low-lying states, were extracted from the measured cross sections. These were used to calculate reduced transition probabilities, spectroscopic quadrupole moments, and rotational invariant shape parameters, providing enhanced precision and expanding on previous studies. The experimental data were compared within several theoretical frameworks, including the generalized triaxial rotor model, configuration interaction shell-model calculations, and computations within the combined frameworks of relativistic density functional theory and the five-dimensional collective Hamiltonian. The results demonstrate a good agreement with the experimental data and, in conjunction with calculations using a two-state mixing model, support significant triaxiality and strong mixing between the $0_1^{+}$ and $0_2^{+}$ states. This results in the magnitudes of their respective quadrupole deformations $[{\beta }_{\text{rms}}(0_1^{+})=0.228(3),{\beta }_{\text{rms}}(0_2^{+})=0.273(1)]$ being more similar than previously observed. The implications of these results for understanding the complex shape coexistence phenomena, the role of triaxiality, and shape evolution along the Ge isotopic chain are discussed.

   nucl-exPRC(2025)·1 citation
6. 06*

   Pseudoscalar heavy-quarkonium hadroproduction from nonrelativistic fragmentation at NLL/NLO${}^{+}$

   Francesco Giovanni Celiberto🇪🇸 · Francesca Lonigro🇪🇸

   We investigate the inclusive hadroproduction of pseudoscalar heavy quarkonia, ${\eta }_c$ and ${\eta }_b$ mesons, in high-energy proton collisions. Our framework bases on the single-parton collinear fragmentation within a variable-flavor number scheme, tailored to describe the moderate to large transverse momentum regime. To this end, we construct a new set of collinear fragmentation functions, denoted as NRFF1.0, which evolve via standard DGLAP equations with a consistent treatment of flavor thresholds. Initial conditions for all parton-induced channels are computed using next-to-leading-order nonrelativistic QCD. We perform our analysis within the NLL/NLO${}^{+}$ hybrid factorization framework, employing the JETHAD numerical interface together with the symJETHAD symbolic engine. These tools allow us to deliver predictions for high-energy observables sensitive to quarkonium final states at 13 TeV LHC. To the best of our knowledge, the NRFF1.0 sets represent the first-ever release of collinear fragmentation functions for heavy quarkonia that consistently includes all partonic channels within collinear factorization.

   ↳ hep-phhep-exhep-thnucl-ex+1PRD(2025)·17 citations
7. 07*

   Unlocking New Frontiers: The Versatile Potential of the Brazilian Multipurpose Reactor

   Luiz P. de Oliveira · Alexandre P.S. Souza · Carlos G.S. Santos · Iberê R.S. Júnior · Barbara P.G. Silva · Marco A.S. Pereira · Frederico A. Genezini · José A. Perrotta

   The multipurpose nature of nuclear research reactors has been investigated. This class of reactors has gained momentum within the international community, given the multiple benefits of nuclear technology in medicine, agriculture, industry, and the development of new materials, being characterized by the simultaneous use of several applications. In this context, Brazil has recently joined the group of countries with multipurpose reactor projects. The Brazilian Multipurpose Reactor (RMB) will be Brazil's new neutron source, with a thermal power of $30$ $MW$, with a core flux on the order of $\varphi =4\times 10^{14}$ $n/c{m}^{2}s$ and a power density of $312.5$ $W/c{m}^3$, ensuring the production of radioisotopes, material and fuel irradiation testing, and neutron beam applications. In this work, the demand for neutron fluxes in different irradiation targets is investigated by Monte Carlo simulations under a perturbation caused by a highly neutron-absorbing material, the Gadolinium-157 (Gd-157) isotope. The results show that Molybdenum-99 (Mo-99) production is not affected by the Gd-157 target, and the minimum proposed thermal neutron flux for the reactor's activity (${\varphi }_{min}=5.1\times 10^{12}$ $n/c{m}^{2}s$) is guaranteed even at maximum operational capacity. The potential production of Terbium (Tb) isotopes for nuclear medicine applications in the RMB is briefly discussed.

   ↳ physics.ins-detnucl-ex2 citations
8. 08*

   Microscopic description of the proton halo in ${}^{12}$N

   K. Y. Zhang🇨🇳 · X. X. Lu🇬🇧

   The year 2025 marks the 40th anniversary of the discovery of halo nuclei and the 15th anniversary of the development of the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). In this work, we present the first DRHBc description of the proton halo phenomenon. The available experimental proton separation energies and empirical matter root-mean-square (rms) radii are reasonably well reproduced for the $N=5$ isotones, ranging from the stable nucleus ${}^9$Be to the drip-line nucleus ${}^{12}$N. In particular, the DRHBc theory captures the abrupt increase in rms radii at ${}^{12}$N, unambiguously corroborating its proton halo structure. The formation of this halo is attributed to the occupation of a weakly bound orbital with dominant $1p$ components by the valence proton, which contributes approximately $90\%$ to the diffused proton density of ${}^{12}$N at large distances from the nuclear center. A shape decoupling between the prolate core and the oblate halo in ${}^{12}$N is predicted.

   ↳ nucl-thnucl-exPLB(2025)·9 citations
9. 09*

   Enhancing the mass resolving power of FRIB's proposed high-voltage MR-ToF mass separator and spectrometer: addressing non-ideal conditions

   Christian Michael Ireland🇺🇸 · Franziska Maria Maier🇺🇸 · Einstein Dhayal · Erich Leistenschneider🇺🇸 · Ryan Ringle🇺🇸 · Austin Sjaarda

   Multi-reflection time-of-flight mass separators and spectrometers (MR-ToF MSs) are indispensable tools at radioactive ion beam (RIB) facilities. These electrostatic ion beam traps act as highly selective mass separators and high-precision mass spectrometers for rare and exotic nuclei. When well-tuned and designed to minimize higher-order flight-time aberrations, state-of-the-art MR-ToF MSs approach, and slightly exceed, mass resolving powers of \( m / \Delta m = 10^6 \). Achieving \( m / \Delta m > 3 \cdot 10^6 \) would provide the ability to resolve \( >90\% \) of all known isomeric states with half-lives above 10~\text{ms}. However, the ability to mass separate in all practical setups is limited by non-ideal conditions which place such resolving powers out of reach. To this end, we present a simulated analysis of these conditions in the newly proposed high-voltage MR-ToF MS for the Facility for Rare Isotope Beams (FRIB). It is expected to store ions at 30~\text{keV} beam energy and increase ion throughput by two orders of magnitude compared to current devices. Existing efforts to mitigate the effects of non-ideal conditions employed for current MR-ToF devices storing ions at \( <3~\text{keV} \) beam energy will already enable mass resolving powers approaching \( 10^6 \) for FRIB's high-voltage MR-ToF device. Simulations of newly proposed mitigation strategies show that even mass resolving powers approaching \( 10^7 \) might become feasible.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2026)·2 citations
10. 10*

    Efficiency correction of particle-averaged quantities

    Masakiyo Kitazawa🇯🇵 · ShinIchi Esumi🇯🇵 · Takafumi Niida🇯🇵 · Toshihiro Nonaka🇯🇵

    We derive analytic formulas to reconstruct particle-averaged quantities from experimental results that suffer from the efficiency loss of particle measurements. These formulas are derived under the assumption that the probabilities of observing individual particles are independent. The formulas do not agree with the conventionally used intuitive formulas.

    ↳ physics.data-anhep-exhep-phnucl-ex+1PTEP(2026)·0 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.