Tue·Apr 8, 2025Tuesday·April 8, 2025

1. 01*

   Astrophysical significance of the isomer ${}^{119m}$Ag demonstrated through direct mass measurement

   F. Rivero🇺🇸 · M. Brodeur🇺🇸 · J.A. Clark🇺🇸 · B. Liu🇺🇸 · G.W. Misch · M.R. Mumpower🇺🇸 · W.S. Porter🇺🇸 · D. Ray🇨🇦 · G. Savard🇺🇸 · T.M. Sprouse🇺🇸 · A.A. Valverde🇺🇸 · D.P. Burdette🇺🇸 and 9 other authors

   The abundance of elements heavier than iron produced via the astrophysical rapid-neutron capture process depends sensitively on the atomic mass of the involved nuclei as well as the behavior of a few special types of nuclear isomers called astromers. High-precision mass measurements of ${}^{119}$Cd, ${}^{119}$Ag and their respective isomeric states have been performed with the Phase Imaging-Ion Cyclotron Resonance (PI-ICR) method with a precision of $\delta m/m\approx 10^{-8}$ using the Canadian Penning Trap (CPT). The ground state mass excess, as well as the excitation energy, agrees with recent Penning Trap measurements from JYFLTRAP. Network calculations using these new measurements revealed that, contrary to previous expectations, ${}^{119m}$Ag behaves as an astromer which significantly affects the population of ${}^{119}$Ag.

   nucl-exPRC(2025)·1 citation
2. 02*

   Nuclear Physics and the European Particle Physics Strategy Update 2026

   L.M. Fraile🇪🇸 · J.J. Gaardhøje🇩🇰 · U. van Kolck🇮🇹 · H. Moutarde🇫🇷 · N. Patronis🇬🇷 · M.T. Peña🇵🇹 · L. Popescu🇧🇪 · V. Wagner🇨🇿 · E. Widmann (on behalf of NuPECC)🇦🇹

   This document provides input to the update of the European Strategy for Particle Physics in fields that are related to Nuclear Physics as described in the NuPECC Long Range Plan 2024 (arXiv:2503.15575).

   nucl-exnucl-th0 citations
3. 03*

   Long-range transverse momentum correlations and radial flow in Pb$-$Pb collisions at the LHC with ALICE

   ALICE Collaboration

   This Letter presents measurements of long-range transverse-momentum correlations using a new observable, $v_0(p_{\mathrm{T}})$, serving as a probe of event-by-event radial-flow fluctuations, the underlying radial expansion, and the medium properties in heavy-ion collisions. Results are reported for inclusive charged particles, pions, kaons, and protons across various centrality intervals in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV, recorded by the ALICE detector. A pseudorapidity-gap technique, similar to that used in anisotropic-flow studies, is employed to suppress short-range correlations. At low $p_{\mathrm{T}}$, a characteristic mass ordering consistent with hydrodynamic collective flow is observed. At higher $p_{\mathrm{T}}$ ($>3$ GeV/$c$), protons exhibit larger $v_0(p_{\mathrm{T}})$ than pions and kaons, in agreement with expectations from quark-recombination models. Comparisons to viscous hydrodynamic calculations with varying bulk viscosity and equation of state demonstrate the sensitivity of the $v_0(p_{\mathrm{T}})$ observable to these key medium properties. The findings establish $v_0(p_{\mathrm{T}})$ as a valuable addition to the set of observables used in Bayesian analyses for extracting the transport properties and constraining the equation of state of strongly interacting matter, while also helping to systematically explore its sensitivity and impact within such global studies.

   nucl-exhep-exPRL(2026)·35 citations
4. 04*

   Measurement of substructure-dependent suppression of large-radius jets with charged particles in Pb+Pb collisions with ATLAS

   ATLAS Collaboration

   Measurements of jet substructure in Pb+Pb collisions provide key insights into the mechanism of jet quenching in the hot and dense QCD medium created in these collisions. This Letter presents a measurement of the suppression of large-radius jets with a radius parameter of $R=1.0$ and its dependence on the jet substructure. The measurement uses 1.72 nb${}^{-1}$ of Pb+Pb data and 255 pb${}^{-1}$ of $pp$ data, both at $\sqrt{s_{{}_{\mathrm{NN}}}}=5.02$ TeV, recorded with the ATLAS detector at the Large Hadron Collider. Large-radius jets are reconstructed by reclustering $R=0.2$ calorimetric jets and are measured for transverse momentum above $200$ GeV. Jet substructure is evaluated using charged-particle tracks, and the overall level of jet suppression is quantified using the jet nuclear modification factor ($R_{\mathrm{AA}}$). The jet $R_{\mathrm{AA}}$ is measured as a function of jet $p_{\mathrm{T}}$, the charged $k_t$ splitting scale ($\sqrt{d_{12}}$), and the angular separation ($\Delta R_{12}$) of two leading sub-jets. The jet $R_{\mathrm{AA}}$ gradually decreases with increasing $\sqrt{d_{12}}$, implying significantly stronger suppression of large-radius jets with larger $k_t$ splitting scale. The jet $R_{\mathrm{AA}}$ gradually decreases for $\Delta R_{12}$ in the range $0.01-0.2$ and then remains consistent with a constant for $\Delta R_{12}\gtrsim 0.2$. The observed significant dependence of jet suppression on the jet substructure will provide new insights into its role in the quenching process.

   nucl-exhep-exPLB(2025)·12 citations
5. 05*

   Observation of coherent $\varphi$(1020) meson photoproduction in ultraperipheral PbPb collisions at $\sqrt{s_{\text{NN}}}$ = 5.36 TeV

   CMS Collaboration

   The first observation of coherent $\varphi$(1020) meson photoproduction off heavy nuclei is presented using ultraperipheral lead-lead collisions at a center-of-mass energy per nucleon pair of 5.36 TeV. The data were collected by the CMS experiment and correspond to an integrated luminosity of 1.62 $\mu$b${}^{-1}$. The $\varphi$(1020) meson signals are reconstructed via the K${}^{+}$K${}^{-}$ decay channel. The production cross section is presented as a function of the $\varphi$(1020) meson rapidity in the range 0.3 $<$ $|y|$ $<$ 1.0, probing gluons that carry a fraction of the nucleon momentum ($x$) around $10^{-4}$. The observed cross section exhibits little dependence on rapidity and is significantly suppressed, by a factor of $\sim$5, compared to a baseline model that treats a nucleus as a collection of free nucleons. Theoretical models that incorporate the nuclear shadowing effect generally provide a better description of the $\varphi$(1020) data than those incorporating gluon saturation. This study establishes a powerful new tool for exploring nuclear effects and nuclear gluonic structure in the small-$x$ regime at a unique energy scale bridging the perturbative and nonperturbative quantum chromodynamics domains.

   nucl-exhep-exPRL(2025)·15 citations
6. 06*

   Fragmentation functions for axial-vector heavy tetraquarks: A TQ4Q1.1 update

   Francesco Giovanni Celiberto🇪🇸

   We present and discuss the release of novel sets of collinear, variable-flavor-number-scheme fragmentation functions for axial-vector, fully heavy $T_{4c}(1^{+-})$ and $T_{4b}(1^{+-})$ tetraquarks. Working within the single-parton approximation at leading power and employing nonrelativistic QCD factorization adapted for tetraquark Fock states, we model the initial-scale fragmentation input using a recent calculation for the constituent heavy-quark channel. Standard DGLAP evolution is then applied, ensuring consistent implementation of evolution thresholds. To support phenomenology, we investigate NLL/NLO${}^{+}$ rates for tetraquark-jet systems at the HL-LHC and FCC from (sym)JETHAD. This study further integrates exotic matter explorations with precision QCD calculations.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2025)·18 citations
7. 07*

   Physics with high-luminosity proton-nucleus collisions at the LHC

   D. d'Enterria🇨🇭 · C. A. Flett🇫🇷 · I. Grabowska-Bold🇵🇱 · C. Hadjidakis🇫🇷 · P. Kotko🇵🇱 · A. Kusina🇵🇱 · J.P. Lansberg🇫🇷 · R. McNulty🇮🇪 · M. Rinaldi🇮🇹 · L. Bonechi🇮🇹 · R. Bruce🇨🇭 · C. Da Silva🇺🇸 and 20 other authors

   The physics case for the operation of high-luminosity proton-nucleus ($pA$) collisions during Run 3 and 4 at the LHC is reviewed. The collection of $\mathcal{O}$(1-10 pb${}^{-1}$) of proton-lead ($p$Pb) collisions at the LHC will provide unique physics opportunities in a broad range of topics including proton and nuclear parton distribution functions (PDFs and nPDFs), generalised parton distributions (GPDs), transverse momentum dependent PDFs (TMDs), low-$x$ QCD and parton saturation, hadron spectroscopy, baseline studies for quark-gluon plasma and parton collectivity, double and triple parton scatterings (DPS/TPS), photon-photon collisions, and physics beyond the Standard Model (BSM); which are not otherwise as clearly accessible by exploiting data from any other colliding system at the LHC. This report summarises the accelerator aspects of high-luminosity $pA$ operation at the LHC, as well as each of the physics topics outlined above, including the relevant experimental measurements that motivate -- much -- larger $pA$ datasets.

   ↳ hep-phhep-exnucl-exnucl-thJ.Phys.G(2025)·6 citations
8. 08*

   Transverse-momentum-dependent pion structures from lattice QCD: Collins-Soper kernel, soft factor, TMDWF, and TMDPDF

   Dennis Bollweg🇺🇸 · Xiang Gao🇺🇸 · Jinchen He🇺🇸 · Swagato Mukherjee🇺🇸 · Yong Zhao🇺🇸

   We present the first lattice quantum chromodynamics (QCD) calculation of the pion valence-quark transverse-momentum-dependent parton distribution function (TMDPDF) within the framework of large-momentum effective theory (LaMET). Using correlators fixed in the Coulomb gauge (CG), we computed the quasi-TMD beam function for a pion with a mass of 300 MeV, a fine lattice spacing of $a=0.06$ fm and multiple large momenta up to 3 GeV. The intrinsic soft functions in the CG approach are extracted from form factors with large momentum transfer, and as a byproduct, we also obtain the corresponding Collins-Soper (CS) kernel. Our determinations of both the soft function and the CS kernel agree with perturbation theory at small transverse separations ($b_{\perp }$) between the quarks. At larger $b_{\perp }$, the CS kernel remains consistent with recent results obtained using both CG and gauge-invariant TMD correlators in the literature. By combining next-to-leading logarithmic (NLL) factorization of the quasi-TMD beam function and the soft function, we obtain $x$-dependent pion valence-quark TMDPDF for transverse separations $b_{\perp }\gtrsim 1$ fm. Interestingly, we find that the $b_{\perp }$ dependence of the phenomenological parameterizations of TMDPDF for moderate values of $x$ are in reasonable agreement with our QCD determinations. In addition, we present results for the transverse-momentum-dependent wave function (TMDWF) for a heavier pion with 670 MeV mass.

   ↳ hep-lathep-exhep-phnucl-ex+1PRD(2025)·33 citations
9. 09*

   Identifying $\alpha$-cluster configurations in ${}^{20}$Ne via ultracentral Ne+Ne Collisions

   Pei Li🇨🇳 · Bo Zhou🇨🇳 · Guo-Liang Ma🇨🇳

   The initial-state geometry in relativistic heavy-ion collisions provides a novel probe to nuclear cluster structure. For ${}^{20}$Ne, a novel approach is proposed to distinguish between the cluster configurations (5$\alpha$ versus $\alpha {+}^{16}$O) in order to gain insight into nuclear structure transitions governed by many-body quantum correlations. Through analytical calculations with the microscopic Brink model and event-by-event simulations using the hydrodynamic framework, we establish the normalized symmetric cumulant NSC (3, 2) and the Pearson coefficient ${\rho }_2(v_2^2,\delta [p_{\mathrm{T}}])$ as quantitative discriminators to reveal enhanced cluster degrees of freedom in the ground state of ${}^{20}$Ne. The ultracentral Ne+Ne collisions at the LHC can experimentally identify these two competing configurations via these flow correlation observables, opening a new paradigm for probing clustering in light nuclei.

   ↳ nucl-thhep-phnucl-exPRL(2026)·15 citations
10. 10*

    Investigation of the baryon time-like electromagnetic form factors in the electron-positron annihilation reactions

    Ju-Jun Xie🇨🇳 · Cheng Chen🇨🇳

    Based on the experimental measurements of the electron-positron annihilation reactions into a baryon ($B$) and anti-baryon ($\bar{B}$) pair, the electromagnetic form factors of hyperons in the time-like region can be investigated within the vector meson dominance model. The theoretical model parameters are determined by fitting them to the total cross sections of the process $e^{+}{e}^{-}\to B\bar{B}$, and it is found that the current experimental data on the baryon electromagnetic form factors in the time-like region can be well reproduced. In addition to the total cross sections, the electromagnetic form factors $G_E$ and $G_M$, and the charge radii of those baryons are also estimated, which are in agreement with the experimental data. On the other hand, we have also investigated the nonmonotonic behavior of the time-like baryon electromagnetic form factors, and it is found that the previously proposed periodic behaviour of the nucleon time-like electromagnetic form factor is not confirmed. However, we do observe the nonmonotonic structures in the line shape of the baryon effective form factors or the ratio $|G_E/G_M|$ for the charmed baryon ${\Lambda }_c^{+}$. These features can be naturally explained by incorporating contributions from excited vector states. More precise measurements of the $e^{+}{e}^{-}\to B\bar{B}$ reaction offer a valuable opportunity to probe the properties of excited vector states, which are at present poorly known. Additionally, comprehensive theoretical and experimental studies of baryon timelike electromagnetic form factors can provide critical insights into the underlying mechanisms of electron-positron annihilation processes.

    ↳ hep-phhep-exnucl-exnucl-thPoS(2025)·0 citations
11. 11*

    The role of the screening potential in the deuteron-deuteron thermonuclear reaction rates

    Faisal Etminan🇮🇷

    The deuteron-deuteron (D-D) thermonuclear reaction rates in metallic environments (considering the electron screening effects) is calculated using the S-factor functions which were obtained by fitting to low-energy data on D-D reactions. For this purpose, a fitted S-factor model based on the NACRE compilation is employed. This limited the energy range of Big Bang nucleosynthesis (BBN) for the ${}^2\text{H}{\left(d,p\right)}^3\text{H}$ and ${}^2\text{H}{\left(d,n\right)}^3\text{He}$ reactions. The corresponding Maxwellian-averaged thermonuclear reaction rates of relevance in astrophysical plasmas at temperatures in the range from $10^6$ K to $10^{10}\left(\text{or }1.3\times 10^8\right)$ K are provided in tabular formats. In these evaluations, the screening energy ($U_e$) is assumed to be $100,400,750,1000$ eV and $1250$ eV. This series of values has been selected based on theoretical and experimental studies conducted so far. % Eventually, our numerical analysis suggests that the ratio of the reaction rate with the screening potential to the reaction rate without the screening potential, can be described by the term $\exp \left(4.70+6.50U_e/T_9\right)$ for both ${}^2\text{H}{\left(d,p\right)}^3\text{H}$ and ${}^2\text{H}{\left(d,n\right)}^3\text{He}$ reactions. This series of values has been selected based on theoretical and experimental studies conducted so far.

    ↳ nucl-thnucl-exNPA(2026)·0 citations
12. 12*

    Finite density signatures of confining and chiral dynamics in QCD thermodynamics and fluctuations of conserved charges

    Yi Lu🇨🇳 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳 · Jan M. Pawlowski🇩🇪

    We evaluate thermodynamic observables such as pressure, baryon number, entropy and energy density, as well as the second and fourth order baryon number cumulants in the phase structure of QCD. The intertwined confinement and chiral dynamics is resolved within functional QCD, aiming for quantitative accuracy at larger densities. Specifically it is shown that the self-consistent resolution of the confining gluonic background is crucial in particular for even the qualitative properties of the cumulants. Our results are in quantitative agreement with lattice and functional QCD benchmarks at vanishing and small chemical potentials. Moreover, they offer novel insights in the dynamics at larger chemical potentials including the regime of the critical end point. A welcome by-product of this analysis is the computation of the Polyakov loop potential in finite density QCD, which, alongside the aforementioned observables, can be used as input and benchmark for effective theory computations at finite density.

    ↳ hep-phhep-thnucl-exnucl-thPRD(2026)·31 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.