Tue·Nov 4, 2025Tuesday·November 4, 2025

1. 01*

   Measurement of Transverse Single-Spin Asymmetries in ${\pi }^0$ and $\eta$ Meson Production in $\sqrt{s}$ = 200 GeV $p^{\uparrow }+p$ Collisions with sPHENIX

   Gregory Mattson🇺🇸

   The sPHENIX experiment is a next-generation collider detector at the Relativistic Heavy Ion Collider (RHIC) designed for rare jet and heavy-flavor probes of Au + Au, $p$ + Au, and polarized $p+p$ collisions. The experiment includes a large acceptance, granular electromagnetic calorimeter and very high-rate data acquisition plus trigger system. In RHIC Run-24, sPHENIX sampled 107 ${\mathrm{pb}}^{-1}$ of collision data with transversely polarized protons at $\sqrt{s}=200$ GeV using an efficient high-$p_T$ photon trigger. This dissertation describes the extraction of transverse single-spin asymmetries in inclusive production of ${\pi }^0$ and $\eta$ mesons decaying into two photons. Such observables are sensitive to multi-parton correlations in the proton, which are related to transverse-momentum dependent (TMD) effects. The new sPHENIX data set allows for significant extension of the kinematic range covered by previous RHIC mid-rapidity measurements. The results are corrected for background contributions and three different sources of systematic uncertainties are considered: the calculation method, the method of background subtraction, and contributions from possible false asymmetries due to instrumental effects. The results are presented and compared to existing measurements from the PHENIX experiment.

   nucl-ex0 citations
2. 02*

   First Study of Exclusive Production of Multi-Hadron Final States in Ultraperipheral Collisions

   Amrit Gautam (for the ALICE Collaboration)

   The study of exclusive photoproduction of multi-hadron final states in ultra-peripheral collisions (UPCs) provides a unique avenue to explore quantum chromodynamics (QCD) and the nature of resonances emerging from gluonic interactions. The ALICE Collaboration has recently performed measurements of exclusive four-pion photoproduction using Run 2 data, favoring the presence of two resonances. However, the underlying nature of these resonances remains poorly understood. The enhanced capabilities of the ALICE detector during Run 3 open new opportunities for the study of multi-pion final states, including four and six-pion systems, and processes involving charmonium decays into four-hadron final states. These studies provide an invaluable way to probe the dynamics of highly dense gluonic matter and the interplay between resonant and non-resonant contributions in hadronic systems. In this paper, we outline the ALICE program focused on these analyses.

   nucl-ex0 citations
3. 03*

   Investigating charm-quark dynamics in the QGP via the charm-hadron elliptic flow in Pb-Pb collisions with ALICE

   Marcello Di Costanzo (for the ALICE Collaboration)🇮🇹

   In these proceedings, the elliptic flow ($v_2$) measurement of prompt and non-prompt charm hadrons - originating respectively from the fragmentation of a charm quark and from the decay of hadrons with beauty-quark content - in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.36\text{TeV}$, using the latest data collected during LHC Run 3 by the ALICE detector, is presented. The analysis is performed at midrapidity ($|y|<0.8$), and hadronic decay channels are used to reconstruct the signal candidates. The $v_2$ coefficient is measured via the Scalar Product (SP) technique. The prompt $v_2$ in semicentral collisions is reported for the $D^0$, $D^{+}$, $D_s^{+}$ mesons and, for the first time, for the ${\Lambda }_c^{+}$ baryon. These results achieve unprecedented precision and low-$p_{\mathrm{T}}$ reach for the D mesons and highlight the first observation of the splitting of baryon and meson elliptic flow at intermediate $p_{\mathrm{T}}$ in the charm sector. The $v_2$ is also measured for prompt $D^0$, $D^{+}$ and $D_s^{+}$ in peripheral collisions, offering new insights into the features of the fireball generated in ultrarelativistic heavy-ion collisions. Lower $v_2$ values are observed for non-prompt $D^0$ and ${\Lambda }_c^{+}$ hadrons in semicentral collisions, as expected from the larger beauty-quark mass.

   nucl-exhep-exPoS(2026)·2 citations
4. 04*

   sPHENIX measurements of heavy flavor production in $p$+$p$ collisions

   Xudong Yu (On behalf of the sPHENIX Collaboration)🇨🇳

   sPHENIX is the first new collider detector experiment dedicated to heavy-ion physics since the LHC began collecting data. Successfully commissioned in 2023-2024, one of its standout features is a streaming-capable tracking system that enables the collection of large, unbiased $p$+$p$ datasets-previously unattainable at the Relativistic Heavy Ion Collider (RHIC). Leveraging this capability, sPHENIX recorded over 100 billion unbiased $p$+$p$ collisions at 200 GeV during Run 24. This unprecedented dataset unlocks a high-precision open heavy flavor physics program with extended low-$p_T$ reach, spanning both charm and beauty sectors. These proceedings present the progress in the analysis of open heavy flavor in the $p$+$p$ dataset. From one hour of data and early-stage calibrations, we see observations of $D^0$ mesons and evidence of ${\Lambda }_c^{+}$ in $p$+$p$ collisions for the first time at RHIC. These resonances will allow for novel physics measurements to be performed for the first time at RHIC.

   nucl-exhep-exPoS(2026)·0 citations
5. 05*

   Observation of oscillations and near-barrier suppression in the fusion of ${}^{20}$O + p

   H. Desilets🇺🇸 · Rohit Kumar🇺🇸 · R. T. deSouza🇺🇸 · S. Hudan🇺🇸 · C. Ciampi🇫🇷 · A. Chbihi🇫🇷 · K. W. Brown🇺🇸 · Varinderjit Singh🇺🇸 · B. Pinheiro🇧🇷 · J. L. Ferreira🇧🇷 · J. Lubian🇧🇷

   Using an active target detector, the fusion excitation function for ${}^{20}$O + ${}^1$H was measured for the first time. Near the barrier, the fusion cross section manifests an oscillatory behavior with broad peaks $\sim$50-100 keV wide. The presence of these peaks likely reflects the low density of low-angular-momentum states in the quasibound regime. R-matrix coupled channel (CC) calculations that include the first excited 2${}^{+}$ state in ${}^{20}$O are able to reproduce the observed oscillations. However, one channel CC calculations fail to reproduce the decrease in the sub-barrier cross section experimentally observed.

   nucl-exPLB(2026)·1 citation
6. 06*

   Three-dimensional sizes and shapes of pion emission in heavy-ion collisions

   Daniel Kincses🇭🇺 · Emese Arpasi🇭🇺 · Laszlo Kovacs🇭🇺 · Marton Nagy🇭🇺 · Mate Csanad🇭🇺

   In the era of precision measurements in high-energy heavy-ion physics, there is an increasing expectation towards phenomenological and theoretical studies to provide a better description of data. In recent years, multiple experiments have confirmed through two-pion Bose-Einstein correlation measurements that the shape of the two-pion pair source can be well described by Levy-stable distributions. However, direct comparisons of new phenomenological results with the data are still needed to understand the underlying phenomena and learn more about the nature of pion emission. In this paper, we present a three-dimensional analysis of the two-pion source in Monte-Carlo simulations of Au+Au collisions at 200 GeV per nucleon collision energy, and discuss a detailed comparison with the most recent centrality-dependent measurements from the PHENIX Collaboration.

   nucl-exhep-phnucl-thEPJC(2026)·5 citations
7. 07*

   Search for dibaryon resonances in the reactions $dd\to dd\pi \pi$ and $pd\to pd\pi \pi$

   Yu.N. Uzikov🇷🇺 · A.A.Temerbayev🇰🇿 · N.T.Tursunbayev🇰🇿

   The isoscalar dibaryon resonance $D_{03}(2380)$, discovered at WASA@COSY in the total cross section of the reaction $pn\to d{\pi }^0{\pi }^0$ and in the elastic pn scattering in the energy range corresponding to the invariant mass of the pn system of 2380 MeV, can reveal itself in the $pd\to pd\pi \pi$ and $dd\to dd\pi \pi$ reactions at higher energies due to deuteron excitation in the $t$ channel. In this paper, the cross sections of these reactions are estimated based on the model of the reaction $pn\to d{\pi }^0{\pi }^0$, proposed earlier by Platonova and Kukulin.

   ↳ nucl-thnucl-ex0 citations
8. 08*

   In-medium mass shifts of $B_c^{(\ast )},B_s^{(\ast )}$ and $D_s^{(\ast )}$ mesons

   K. Tsushima🇧🇷 · S.L.P.G. Beres🇧🇷 · G.N. Zeminiani🇧🇷

   We present our predictions for the Lorentz scalar mass shifts of two-flavored heavy mesons, $B_c^{(\ast )},B_s^{(\ast )}$ and $D_s^{(\ast )}$ in symmetric nuclear matter. The in-medium mass shifts are estimated by evaluating the lowest order one-loop self-energies of the mesons based on a flavor-SU(5) effective Lagrangian approach. In-medium properties necessary for the estimates are calculated by the quark-meson coupling (QMC) model. The enhanced self-energies of the mesons in symmetric nuclear matter relative to those in free space, yield the negative mass shifts of these mesons.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJ Web Conf.(2026)·0 citations
9. 09*

   Large-scale shell-model investigation of $2\nu$ECEC in ${}^{132}$Ba and ${}^{78}$Kr

   Deepak Patel🇮🇳 · Praveen C. Srivastava🇮🇳

   We present a theoretical investigation of two-neutrino double electron capture ($2\nu$ECEC) in ${}^{132}$Ba and ${}^{78}$Kr based on large-scale shell-model calculations. The nuclear matrix elements (NMEs) for the $2\nu$ECEC process in ${}^{132}$Ba and ${}^{78}$Kr are calculated using the SN100PN and GWBXG effective interactions, respectively. The reliability of the employed interactions is first examined through a comparison of the calculated and experimental spectroscopic properties of the parent, intermediate, and granddaughter nuclei involved in the decay. We also examine the cumulative contribution of the $2\nu$ECEC NME with respect to the $1^{+}$ state energies in the intermediate nuclei. The present results provide an updated and improved shell-model estimate of the $2\nu$ECEC NME and half-life for ${}^{78}$Kr relative to earlier studies, and a baseline theoretical prediction for ${}^{132}$Ba that may assist future experimental efforts in constraining this rare decay mode.

   ↳ nucl-thnucl-exEPJA(2026)·0 citations
10. 10*

    Skewness-dependent moments of the pion GPD from nonlocal quark-bilinear correlators

    Xiang Gao🇺🇸 · Swagato Mukherjee🇺🇸 · Qi Shi🇺🇸 · Fei Yao🇺🇸 · Yong Zhao🇺🇸

    We present lattice QCD calculations of the odd Mellin moments of pion valence-quark generalized parton distribution (GPD) up to fifth order, $⟨x^4⟩$, and for the skewness range $[-0.33,0]$ using operator product expansion of bilocal quark-bilinear operators. The calculations are performed on an ensemble with lattice spacing $a=0.04\mathrm{fm}$ and valence pion mass $300$ $\mathrm{MeV}$, employing boosted pion states with momenta up to 2.428 GeV and momentum transfers reaching 2.748 GeV${}^2$. We employ ratio-scheme renormalization and next-to-leading-logarithmic resummed perturbative matching. At zero skewness, our results are consistent with previous lattice studies. By combining matrix elements at multiple values of skewness and momentum transfer, skewness-dependent moments are obtained through simultaneous polynomiality-constrained fits.

    ↳ hep-lathep-phnucl-exnucl-thPRD(2026)·14 citations
11. 11*

    Accurate and Efficient Emulation of Proton-Deuteron Scattering via the Reduced Basis Method and Active Learning

    Alex Gnech🇺🇸 · Xilin Zhang🇺🇸 · Christian Drischler🇺🇸 · R. J. Furnstahl🇺🇸 · Alessandro Grassi🇮🇹 · Alejandro Kievsky🇮🇹 · Laura E. Marcucci🇮🇹 · Michele Viviani🇮🇹

    We introduce highly accurate and efficient emulators for proton-deuteron scattering below the deuteron breakup threshold. We explore two different reduced-basis method strategies: one based on the Kohn variational principle and another on Galerkin projections of the underlying system of linear equations. We use the adaptive greedy algorithm previously developed for two-body scattering for optimal selection of high-fidelity training points in the input parameter space. We demonstrate that these emulators reproduce ab initio hyperspherical harmonics calculations of $R$-matrix elements with remarkable precision, achieving relative errors as low as $10^{-7}$ with a small number of training points, even in regions of strong nonlinear parameter dependence. They also dramatically accelerate the exploration of the scattering predictions in the parameter space, a capability highly desired for calibrating (chiral) three-nucleon forces against scattering measurements. Our formalism can be further generalized to handle nucleon-deuteron scattering above the breakup threshold. These emulator developments will provide valuable tools to accelerate uncertainty quantification and rigorous parameter inference in the study of nuclear forces.

    ↳ nucl-thhep-phnucl-ex6 citations
12. 12*

    Uncertainties in the production of iron-group nuclides in core-collapse supernovae from Monte Carlo variations of reaction rates

    Nobuya Nishimura🇯🇵 · Carla Froehlich · Thomas Rauscher🇨🇭

    Core-collapse supernovae, occurring at the end of massive star evolution, produce heavy elements, including those in the iron peak. Although the explosion mechanism is not yet fully understood, theoretical models can reproduce optical observations and observed elemental abundances. However, many nuclear reaction rates involved in explosive nucleosynthesis have large uncertainties, impacting the reliability of abundance predictions. To address this, we have previously developed a Monte Carlo-based nucleosynthesis code that accounts for reaction rate uncertainties and has been applied to nucleosynthesis processes beyond iron. Our framework is also well suited for studying explosive nucleosynthesis in supernovae. In this paper, we investigate 1D explosion models using the "PUSH method", focusing on progenitors with varying metallicities and initial masses around $M_{\mathrm{ZAMS}}=16M_{\odot }$. Detailed post-process nucleosynthesis calculations and Monte Carlo analyses are used to explore the effects of reaction rate uncertainties and to identify key reaction rates in explosive nucleosynthesis. We find that many reactions have little impact on the production of iron-group nuclei, as these elements are primarily synthesized in the nuclear statistical equilibrium. However, we identify a few "key reactions" that significantly influence the production of radioactive nuclei, which may affect astrophysical observables. In particular, for the production of ${}^{44}$Ti, we confirm that several traditionally studied nuclear reactions have a strong impact. However, determining a single reaction rate is insufficient to draw a definitive conclusion.

    ↳ astro-ph.SRnucl-exnucl-thMNRAS(2026)·1 citation
13. 13*

    Search for Double Beta Plus Decays with NuDoubt++

    Stefan Schoppmann (for the NuDoubt++ Collaboration)🇩🇪

    Double beta plus decay is a rare nuclear disintegration process. Difficulties in its measurement arise from suppressed decay probabilities, experimentally challenging decay signatures and low natural abundances of suitable candidate nuclei. In this presentation, we propose NuDoubt++, a new detector concept to overcome these challenges. It is based on the first-time combination of hybrid and opaque scintillation detector technology paired with novel light read-out techniques. This approach is particularly suitable detecting positron (beta plus) signatures. We expect to discover two-neutrino double beta plus decay modes within 1 tonne-week exposure and are able to probe neutrinoless double beta plus decays at several orders of magnitude improved significance compared to current experimental limits.

    ↳ physics.ins-dethep-exnucl-exPoS(2025)·1 citation
14. 14*

    Incoherent Particle Production in Ultraperipheral Heavy Ion Collisions

    L. A. Harland-Lang🇬🇧

    In this paper, we present the first complete treatment of incoherent photon-initiated production in ultraperipheral heavy ion collisions, focussing on the dilepton and diphoton final states. In the former case we compare to the ATLAS measurement of dielectron production and find that our predictions match the data very well. In the latter case we show that this contribution is too small to explain the observed broad in diphoton acoplanarity background to the purely coherent light-by-light scattering signal. We in addition consider a new `quark emission' topology, which while naively might be expected to dominate the incoherent diphoton production channel, is in fact found to be kinematically suppressed. Finally, we revisit QCD-initiated diphoton production and issue of theoretical uncertainties in this case. We find that this again cannot explain the observed size of the higher acoplanarity background. The production mechanism leading to this background to light-by-light production, and the reason for its observed enhancement in comparison to the dilepton case, therefore remains unclear.

    ↳ hep-phhep-exnucl-exnucl-thPRD(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.