Mon·Apr 21, 2025Monday·April 21, 2025

1. 01*

   Refinement of an analytical capture cross section formula

   Ning Wang🇨🇳

   An analytical formula with high accuracy is proposed for a systematic description of the capture cross sections at near-barrier energies from light to superheavy reaction systems. Based on the empirical barrier distribution (EBD) method, three key input quantities are refined by introducing nuclear surface correction to the Coulomb parameter $z$ for calculating the barrier height, incorporating the reaction $Q$-value and shell correction into the barrier distribution width calculations, and considering the deep inelastic scattering effects of superheavy systems on the barrier radius. With these refinements, not only the accuracy of the calculated barrier height but also the accuracy of the predicted capture cross sections, is substantially improved. The average deviation (in logarithmic scale) between the predicted cross sections and the experimental data for a total of 426 reaction systems with $35<Z_1{Z}_2<2600$ is sharply reduced from 3.485 to 0.113.

   ↳ nucl-thnucl-exCPC(2025)·3 citations
2. 02*

   GeV-level $\gamma$-ray and positron beams produced by collisions of ultra-intense ultra-short laser on high-energy electron beam

   Wanqing Su · Chunwang Ma🇨🇳 · Xiguang Cao · Guoqiang Zhang · Yuting Wang

   Based on collisions between the 100 PW laser and 8 GeV superconducting linear accelerator constructing at the Shanghai hard X-ray free electron laser system (SHINE), the building of GeV-level $\gamma$-ray as well as positron beams are proposed according to particle-in-cell simulations. Key processes are considered involving the nonlinear inverse Compton scattering for $\gamma$-ray generation and the multiphoton Breit-Wheeler process for electron-positron pair production. Regardless of laser polarization, the simulations indicate that $\gamma$-ray beams achieve energy up to 8 GeV, brilliance around 10${}^{27}$ photons/(s mm${}^2$ mrad${}^2$), and emittance as low as 0.1 mm mrad, while positron beams reach energy up to 7 GeV, brilliance around 4 $\times$ 10${}^{24}$ positrons/(s mm${}^2$ mrad${}^2$), and emittance as low as 0.1 mm mrad. Various applications could benefit from the possible high-energy $\gamma$-ray and positron beams built at the SHINE facility, including fundamental physics of strong-field quantum electrodynamics theory validation, nuclear physics, radiopharmaceutical preparation, and imaging, etc.

   ↳ physics.acc-phnucl-ex0 citations
3. 03*

   Productions of ${}_{\Lambda }^3$H, ${}_{\Lambda }^4$H and ${}_{\Lambda }^4$He in different coalescence channels in Au-Au collisions at $\sqrt{s_{NN}}=3$ GeV

   Rui-Qin Wang🇨🇳 · Jun Song🇨🇳 · Mao-Yan Wu🇨🇳 · Huai-Tong Xue🇨🇳 · Feng-Lan Shao🇨🇳

   We study the productions of $\Lambda$-hypernuclei ${}_{\Lambda }^3$H, ${}_{\Lambda }^4$H and ${}_{\Lambda }^4$He in the coalescence mechanism in Au-Au collisions at $\sqrt{s_{NN}}=3$ GeV. Considering the abundance and great importance of baryons and light (hyper-)nuclei on the collision dynamics, we include not only nucleon$+\Lambda$ coalescence but also nucleus+nucleon($\Lambda$) coalescence. We present contributions from different coalescence channels for ${}_{\Lambda }^3$H, ${}_{\Lambda }^4$H and ${}_{\Lambda }^4$He in their productions. We predict the production asymmetry between ${}_{\Lambda }^4$H and ${}_{\Lambda }^4$He, characterized by yield ratios ${}_{\Lambda }^4\text{He}{/}_{\Lambda }^4\text{H}$ and ${(}_{\Lambda }^4\text{H}{-}_{\Lambda }^4\text{He})/{(}_{\Lambda }^4\text{H}{+}_{\Lambda }^4\text{He})$, which can shed light on the existence constraints of the possible neutron-$\Lambda$ bound states ${}_{\Lambda }^{2}n(n\Lambda )$ and ${}_{\Lambda }^{3}n(nn\Lambda )$.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2025)·2 citations
4. 04*

   Expected statistical uncertainties at future $e^{+}{e}^{-}$ colliders

   Hieu Minh Tran🇻🇳 · Sang Quang Dinh🇻🇳 · Trang Quynh Trieu🇻🇳

   In future colliders, the frontiers of luminosity and energy are extended to explore the physics of elementary particles at extremely high precision, and to discover new phenomena suggested from current experimental anomalies. In this letter, we present a simple method to estimate the expected statistical uncertainties of scattering cross sections at future colliders using their conceptual design reports. In particular, the expected statistical uncertainties of muon pair production cross section at the Future Circular Collider (FCC-ee) and the Circular Electron-Positron Collider (CEPC) are calculated. The results can be used to set a goal for systematic uncertainty improvement, to determine the standard model parameters accurately, and to identify the viable parameter space of new physics models.

   ↳ hep-phhep-exnucl-exEPL(2025)·1 citation
5. 05*

   The impact of new ($\alpha$, n) reaction rates on the weak s-process in metal-poor massive stars

   Wenyu Xin · Chun-Ming Yip · Ken'ichi Nomoto · Xianfei Zhang · Shaolan Bi

   Massive stars are significant sites for the weak s-process (ws-process). ${}^{22}$Ne and ${}^{16}$O are, respectively, the main neutron source and poison for the ws-process. In the metal-poor stars, the abundance of ${}^{22}$Ne is limited by the metallicity, so that the contribution of ${}^{22}$Ne($\alpha$, n)${}^{25}$Mg reaction on the s-process is weaker. Conversely, the ${}^{17}$O($\alpha$, n)${}^{20}$Ne reaction becomes more prominent in these stars due to the most abundant ${}^{16}$O in all metallicities. In this work, we calculate the evolution of four metal-poor models ($Z=10^{-3}$) for the Zero-Age Main-Sequence (ZAMS) masses of $M(\mathrm{ZAMS})=$ 15, 20, 25, and 30 M${}_{\odot }$ to investigate the effect of reaction rates on the ws-process. We adopt the new ${}^{17}$O($\alpha$, n)${}^{20}$Ne and ${}^{17}$O($\alpha ,\gamma$)${}^{21}$Ne reaction rates suggested by Best et al. (2013) and ${}^{22}$Ne($\alpha$, n)${}^{25}$Mg and ${}^{22}$Ne($\alpha ,\gamma$)${}^{26}$Mg from Wiescher et al. (2023). The yields of the s-process isotope with updated reaction rates are compared with the results using default reaction rates from JINA REACLIB. We find that the new ${}^{17}$O+$\alpha$ reaction rates increase the ws-process mainly in all the stages, while the new ${}^{22}$Ne+$\alpha$ reaction rates only increase the ws-process in C and Ne burning stages. Updating these new reaction rates would increase the production of ws-process isotopes by tens of times. We also note that for more massive stars, the enhancement by new ${}^{17}$O+$\alpha$ reaction rates become more significant.

   ↳ astro-ph.SRnucl-exnucl-thNucl.Sci.Tech.(2026)·1 citation

* 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.