Fri·Oct 10, 2025Friday·October 10, 2025

1. 01*

   Carbon burning at stellar energies

   S. Courtin🇫🇷 · M. Heine🇫🇷 · E. Monpribat🇫🇷 · J. Nippert🇫🇷

   Fusion reactions with light nuclei play an essential role in understanding the energy production, the nucleosynthesis of chemical elements and the evolution of massive stars. The measurement of key fusion reactions at stellar energies is thus of interest, but highly challenging since the associated cross sections are extremely small, of the sub-nanobarn range. Among these reactions, the fusion of carbon nuclei, which drives the stellar carbon burning phase, is deeply connected with essential microscopic features such as the impact of symmetries, the access to quantum states, emerging of resonances or Pauli repulsion effects. These may manifest themselves in exceptional behaviour of the S-factor of this particular system and the precision of extrapolations to deep sub-barrier energies is limited. The present contribution discusses recent experimental results of the nuclear astrophysics community on the measurement of the carbon + carbon fusion reaction down to the astrophysics region. The interplay between nuclear structure, nucleosynthesis and stellar evolution is addressed.

   nucl-exJ.Phys.Conf.Ser.(2023)·0 citations
2. 02*

   Spectrometry of Captured Highly Charged Ions Produced Following Antiproton Annihilations

   F. P. Gustafsson🇨🇭 · M. Volponi · J. Zielinski🇵🇱 · A. Asare · I. Hwang · S. Alfaro Campos · M. Auzins · D. Bhanushali · A. Bhartia · M. Berghold · R. S. Brusa · K. Calik and 52 other authors

   We report a proof-of-principle study demonstrating the first capture and time-of-flight spectrometry of highly charged ions (HCIs) produced following antiproton annihilations in a Penning-Malmberg trap. A multi-step nested-trap technique was developed using the \aegis\ experiment to identify annihilation-linked captured ions. The trapping and spectrometry of helium and argon ions demonstrates the approach. This work establishes a foundation for the in-trap synthesis of radioactive HCIs and the study of cold nuclear annihilation fragments, with the long-term goal of enabling a sensitive tool for probing the outer nuclear periphery.

   nucl-exphysics.atom-phPRResearch(2026)·1 citation
3. 03*

   Angular Geometry of Atomic Multipole Transitions

   Wesley C. Campbell

   A simple way to calculate Rabi frequencies is outlined for interactions of atomic or nuclear multipole moments with laser fields that focuses on their relative geometry. The resulting expression takes the form of a dot product between the laser polarization and a vector spherical harmonic, thereby naturally connecting to the multipole's far-field spontaneous-emission pattern and providing a way to visualize the interaction. Since the vector spherical harmonics are not yet a standard tool in quantum science, their relevant properties are reviewed. This approach is illustrated in the calculation of a variety of beam effects, yielding both perturbative corrections and some nontrivial cases with non-vanishing coupling.

   ↳ quant-phnucl-exphysics.atom-ph0 citations
4. 04*

   Characterization of a 28 nm $\text{smartpixels}$ ASIC With On-Chip ML for Particle Tracking Detectors

   Benjamin Parpillon · Anthony Badea · Danush Shekar · Cristian Gingu · Giuseppe Di Guglielmo · Tom Deline · Sergey Los · Adam Quinn · Michele Ronchi · Daniel Abadjiev · Doug Berry · Arghya Ranjan Das and 26 other authors

   We present a 28 nm CMOS pixel readout integrated circuit implementing in-pixel analog signal processing and on-chip machine learning data filtering for particle tracking detectors. Our ASIC comprises two $32\times 8$ pixel matrices with a pixel pitch of $25\times 25\mu {\mathrm{m}}^2$, in which each pixel integrates a charge-sensitive amplifier with synchronous auto-zero offset cancellation and a 2-bit flash ADC with programmable thresholds. Two analog front-end architectures, single-ended and differential, are implemented and characterized. Digitized pixel data are combined into row-wise projections and processed by an on-chip, fully combinational neural network classifier for data reduction. Measurements at room temperature using charge injection demonstrate an equivalent noise charge of $54.6{\mathrm{e}}^{-}$ and a threshold dispersion of $\sim$78.2~\unit{\electron} at nominal bias, linear response up to several~\unit{\kilo\electron}, and stable operation at a 10~MHz clock frequency. The neural network output is compared with offline RTL predictions and agrees for $99.06\%$ of $1.5\times 10^5$ test inputs.

   ↳ physics.ins-dethep-exnucl-ex4 citations
5. 05*

   Probing the Neutron Skin with Extreme Collision Geometries in Heavy-Ion Collisions

   Hui Zhang🇨🇳 · Alex Akridge🇺🇸 · Charles J. Horowitz🇺🇸 · Jinfeng Liao🇺🇸 · Hongxi Xing🇨🇳

   Understanding how protons and neutrons are located differently in an atomic nucleus can provide fundamental information on nuclear structure and have far-reaching implications for astrophysics. A precise determination of this important difference, often quantified by the so-called neutron skin thickness, is challenging both theoretically and experimentally. Here we show how one can use a new category of observables in heavy ion collisions to probe the neutron skin thickness of nuclei like ${}^{208}$Pb and ${}^{48}$Ca, by utilizing the asymmetry between neutrons and protons of spectator nucleons in super-central collisions as well as that of participant nucleons in peripheral collisions. Using quantitative simulations, we demonstrate their sensitivity and great potential in constraining neutron skin thickness for both ${}^{208}$Pb and ${}^{48}$Ca nuclei in these extreme event geometries. Furthermore, we propose the asymmetric collisions between ${}^{48}$Ca and ${}^{40}$Ca nuclei as a unique and powerful way to nail down the neutron skin thickness.

   ↳ nucl-thhep-exhep-phnucl-ex5 citations
6. 06*

   Collectivity and isomers in the Pb isotopes

   Praveen C. Srivastava🇮🇳 · Sakshi Shukla🇮🇳

   In the present work, we aim to study collectivity in the Pb isotopes in the framework of nuclear shell model. We have performed shell-model calculations using KHH7B effective interaction. The model space of KHH7B interaction consists of 14 orbitals. We have reported results for even-even ${}^{196-206}$Pb isotopes for spectra and electromagnetic properties. The shell model results for isomeric states are also reported. Our results will be useful to compare upcoming experimental data.

   ↳ nucl-thnucl-ex2 citations
7. 07*

   Determining the \Xi-Nucleus Potential from the Measured Binding Energies of ^15_\Xi^C

   Paing Thit Nyein🇮🇳 · Kyaw Kyaw Naing🇮🇳 · Htun Htun Oo🇲🇲 · M. Yamaguchi🇯🇵 · Hiroyuki Kamada🇯🇵

   The recent observation of the deeply bound \Xi - hypernucleus ^15_\Xi^-C through the IRRAWADDY and KINKA events provided a crucial benchmark for determining the \Xi-nucleus interaction. This work aims to constrain the depth of this potential by calculating the binding energy B_\Xi of the ^15_\Xi C system, which forms a \Xi^- -^14 N bound state. We achieve this by numerically solving the Schroedinger equation for a \Xi hyperon within a phenomenological Woods-Saxon potential, using the stable Numerov method, incorporating the Coulomb interaction. For a potential well depth V_0 = 12 MeV, our calculations yield a 0^+_1 state binding energy of 6.35 MeV and a 1^-_1 state energy of 0.87 MeV. These results are in excellent agreement with the IRRAWADDY event (B_\Xi = 6.27 \pm 0.27 MeV) and the shallower 1^-_1 states (KISO/IBUKI events, B_\Xi \approx 1 MeV), respectively. Assuming \Xi^0 instead of \Xi^-, we predict the ground state 0^+ of _{\Xi^0}^{15}N with (B_{\Xi^0} = 2.636 MeV) by omitting the Coulomb interaction as a first approximation.

   ↳ nucl-thnucl-ex0 citations
8. 08*

   On fluctuation properties of MACS

   Milan Krticka🇨🇿 · Aaron Couture

   The Maxwellian Average Cross Section (MACS) is usually calculated with help of the statistical codes that do not take into account fluctuations of individual resonance parameters. The actual MACS can substantially deviate from its expectation value. This work focuses on description of various sources and aspects of these fluctuations. Simulated resonance sequences considering all the fluctuations involved in the statistical model are used for this purpose. Contribution of various sources of the fluctuations and neutrons with different orbital momenta are thoroughly investigated and described. Impact of available cross section data at low neutron energies is also checked. Based on this analysis simple empirical formulae for estimating relative fluctuations of MACS using solely $s$-wave resonance spacing $D_0$ and the temperature of the stellar environment are derived. It is shown that real nuclei follow the proposed formula well. The expected MACS fluctuations increase with $D_0$ and can be significant. While for isotopes with $D_0$ in eV range the possible deviation from calculated values are small, for nuclei with $D_0$ in the keV range the full-width half-maximum of the expected distribution is larger than about 25\% and 10\% for astrophysically relevant temperatures of $kT=8$ and 30 keV. At least for these nuclei the predictions from statistical codes must be taken with caution.

   ↳ nucl-thnucl-ex0 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.