Thu·Oct 23, 2025Thursday·October 23, 2025

1. 01*

   HADES experimental overview

   Hanna Zbroszczyk (for the HADES Collaboration)🇵🇱

   We report the recent results from the HADES experiment obtained in Au+Au and Ag+Ag collisions at center-of-mass energies per nucleon pair of 2.42 and 2.55 GeV, respectively. In particular, measurements of hadronic and dilepton observables are presented, and prospects for the future experimental program are outlined.

   nucl-exEPJ Web Conf.(2026)·0 citations
2. 02*

   Engineering the shapes of quark-gluon plasma droplets by comparing anisotropic flow in small symmetric and asymmetric collision systems

   STAR Collaboration

   The observation of collective flow phenomena in small collision systems challenges our understanding of quark-gluon plasma (QGP) formation and evolution. This complexity lies in the initial geometries, which are influenced by both nucleon configuration and subnucleonic fluctuations, introducing uncertainties in interpreting flow patterns. We disentangle these contributions through comparative measurements of elliptic ($v_2$) and triangular ($v_3$) flow in asymmetric $d$+Au and symmetric ${}^{16}$O+${}^{16}$O collisions at $\sqrt{s_{NN}}=200$ GeV, which produce medium of comparable sizes but with vastly different initial geometries. The larger $v_2$ in $d$+Au reflects its dominant elliptic geometry, while the similar $v_3$ in both systems is better explained by considering subnucleonic fluctuations. These contrasting flow patterns are quantitatively described by a state-of-the-art hydrodynamic model tuned to large-system Au+Au data, indicating efficient transformation of initial geometries to final-state anisotropies. These results provide evidence for droplet formation in small systems with transport properties that are similar to those observed in large collision systems, consistent with QGP-like behavior.

   nucl-exhep-phnucl-th18 citations
3. 03*

   Beta-decay Half Lives beyond ${}^{54}$Ca: A Systematic Survey of Decay Properties approaching the Neutron Dripline

   W.-J. Ong🇺🇸 · Z. Y. Xu🇺🇸 · R. Grzywacz🇺🇸 · A. Ravlić🇺🇸 · I. Cox🇺🇸 · J. M. Allmond🇺🇸 · T. T. King🇺🇸 · B. C. Rasco🇺🇸 · K. P. Rykaczewski🇺🇸 · H. Schatz🇺🇸 · B. M. Sherrill🇺🇸 · B. Tarasov🇺🇸 and 74 other authors

   In an experiment performed at the Facility for Rare Isotope Beams (FRIB) using the FRIB Decay Station initiator (FDSi), 15 new half lives of isotopes near ${}^{54}$Ca were measured. A new method of extracting lifetimes from experimental data, taking into account the unknown $\beta$-delayed neutron emission branches of very neutron-rich nuclei, was developed to enable systematic uncertainty analysis. The experiment observed a dramatic change in the half-life systematics for the isotopes with neutron number N =34. Beyond N =34, the decline of nuclear lifetime is much slower, leading to longer than anticipated lifetimes for near-dripline nuclei. State-of-the-art shell-model calculations can explain the experimental results for Z$>$19 nuclei, revealing the imprint of shell effects and the need for modification of single-particle neutron states. The results from a newly developed QRPA model with potential for making global predictions were also tested against the experimental results and good agreement was found.

   nucl-exnucl-thPRL(2026)·3 citations
4. 04*

   The strong coupling from the IR to the UV extremes: Determination of ${\alpha }_s$ and prospects from EIC and JLab at 22 GeV

   A. Deur🇺🇸

   We discuss how the Bjorken sum rule allows access to the QCD running coupling ${\alpha }_s$ at any scale, including in the deep infrared IR domain. The Bjorken sum data from Jefferson Lab, together with the world data on ${\alpha }_s$ reported by the Particle Data Group, allow us to determine the running of ${\alpha }_s(Q)$ over five orders of magnitude in four-momentum $Q$. We present two possible future measurements of the running of ${\alpha }_s(Q)$ using the Bjorken sum rule: the first at the EIC, covering the range $1.5<Q<8.7$ GeV, and the second at Jefferson Lab at 22 GeV, covering the range $1.0<Q<4.7$ GeV.

   ↳ hep-phhep-exnucl-exPoS(2026)·1 citation
5. 05*

   The Regulated GeAs Cycles with the New ${}^{63}$Ga(p,$\gamma$)${}^{64}$Ge and ${}^{64}$Ge(p,$\gamma$)${}^{65}$As Reaction Rates and Their Impact on the GS 1826$-$24 Clocked Bursts and SAX J1808.4$-$3658 Photospheric Radius Expansion Bursts

   Yi Hua Lam🇨🇳 · Ning Lu🇨🇳 · Alexander Heger🇦🇺 · Zi Xin Liu🇨🇳 · Zac Johnston🇺🇸 · Hidetoshi Yamaguchi🇯🇵

   The ${}^{63}$Ga(p,$\gamma$)${}^{64}$Ge and ${}^{64}$Ge(p,$\gamma$)${}^{65}$As thermonuclear reactions connect the ZnGa and GeAs cycles by diverting the flow of the rapid proton capture process from ${}^{63}$Ga to ${}^{65}$As. Changes in these two reaction rates regulate the ZnGa and GeAs cycles and may affect the modeled properties matching with the observed counterparts of a type I X-ray burster. We implement the latest ${}^{63}$Ga(p,$\gamma$)${}^{64}$Ge and ${}^{64}$Ge(p,$\gamma$)${}^{65}$As reaction rates to the state-of-the-art self-consistent one-dimensional multi-zone thermo-hydrodynamic code, KEPLER, to study the influence of these new reaction rates on the models of the GS 1826$-$24 clocked burster and SAX J1808.4$-$3658 photospheric radius expansion burster. Both new reaction rates obtained by Lu et al. [Phys. Rev. C 110, 065804 (2024)] are determined from complementing the experimental input with the nuclear spectroscopic information deduced from the full pf-shell space configuration-interaction shell-model calculations. By constraining the models on reproducing the observed burst peak, light-curve profile, fluence, and recurrence time, we find that the impact of the newly measured proton thresholds and respective proton-capture reactions on the burst light-curve profile of the GS 1826$-$24 clocked burster is, in fact, not as significant as claimed by Zhou et al. [Nat. Phys. 19, 1091 (2023)]. With or without the inclusion of the newly determined reaction rate of the highly influential ${}^{22}$Mg($\alpha$,p)${}^{25}$Al reaction, the impact of the new ${}^{63}$Ga(p,$\gamma$)${}^{64}$Ge and ${}^{64}$Ge(p,$\gamma$)${}^{65}$As reaction rates on SAX J1808.4$-$3658 photospheric radius expansion bursts is evident. Our finding indicates that the models reproducing the 2002 October epoch of SAX J1808.4$-$3658 photospheric radius expansion burster is more sensitive to the uncertainties of thermonuclear reaction rates.

   ↳ astro-ph.HEnucl-exnucl-thApJ(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.