Fri·Jul 7, 2023Friday·July 7, 2023

1. 01*

   Effects of Hoyle state de-excitation on $\nu p$-process nucleosynthesis and Galactic chemical evolution

   Hirokazu Sasaki🇺🇸 · Yuta Yamazaki · Toshitaka Kajino🇨🇳 · Grant J. Mathews🇺🇸

   The partcle-induced hadronic de-excitation of the Hoyle state in ${}^{12}$C induced by inelastic scattering in a hot and dense plasma can enhance the triple-alpha reaction rate. This prevents the production of heavy nuclei within the neutrino-driven winds of core-collapse supernovae and raises a question as to the contribution of proton-rich neutrino-driven winds as the origin of $p$-nuclei in the solar system abundances. Here we study $\nu p$-process nucleosynthesis in proton-rich neutrino-driven winds relevant to the production of ${}^{92,94}\mathrm{Mo}$ and ${}^{96,98}\mathrm{Ru}$ by considering such particle-induced de-excitation. We show that the enhancement of the triple-alpha reaction rate induced by neutron inelastic scattering hardly affects the $\nu p$-process, while the proton scattering contributes to the nucleosynthesis in proton-rich neutrino-driven winds at low temperature. The associated enhanced triple-alpha reaction rate decreases the production of ${}^{92,94}\mathrm{Mo}$ and ${}^{96,98}\mathrm{Ru}$ in a wind model of ordinary core-collapse supernovae. On the other hand, the abundances of these $p$-nuclei increase in an energetic hypernova wind model. Hence, we calculate the galactic chemical evolution of ${}^{92,94}\mathrm{Mo}$ and ${}^{96,98}\mathrm{Ru}$ by taking account of both contributions from core-collapse supernovae and hypernovae. We show that the hypernova $\nu p$-process can enhance the calculated solar isotopic fractions of ${}^{92,94}\mathrm{Mo}$ and ${}^{96,98}\mathrm{Ru}$ and make a significant impact on the GCE of $p$-nuclei regardless of the particle-induced Hoyle state de-excitation.

   ↳ astro-ph.HEastro-ph.GAnucl-exnucl-thPLB(2024)·6 citations
2. 02*

   Pion PDFs confronted by Fixed-Target Charmonium Production

   Wen-Chen Chang🇹🇼 · Chia-Yu Hsieh🇹🇼 · Yu-Shiang Lian🇹🇼 · Jen-Chieh Peng🇺🇸 · Stephane Platchkov🇫🇷 · Takahiro Sawada🇯🇵

   The pion, as the Goldstone boson of the strong interaction, is the lightest QCD bound state and responsible for the long-range nucleon-nucleon interaction inside the nucleus. Our knowledge on the pion partonic structure is limited by the existing Drell-Yan data which are primarily sensitive to the pion valence-quark distributions. The recent progress of global analysis of pion's parton distribution functions (PDFs) utilizing various experimental approaches are introduced. From comparisons between the pion-induced $J/\psi$ and $\psi (2S)$ production data with theoretical calculations using the CEM and NRQCD models, we show how these charmonium production data could provide useful constraints on the pion PDFs.

   ↳ hep-phhep-exnucl-exAAPPS Bull.(2023)·2 citations
3. 03*

   Collective flow and the fluid behavior in p/d/${}^3$He+Au collisions at $\sqrt{s_{NN}}=200$ GeV

   Zeming Wu🇨🇳 · Baochi Fu🇨🇳 · Shujun Zhao🇨🇳 · Runsheng Liu🇨🇳 · Huichao Song🇨🇳

   By varying the intrinsic initial geometry, the p/d/${}^3$He+Au collisions at the Relativistic Heavy Ion Collider (RHIC) provide a unique opportunity to understand the collective behavior and probe the possible sub-nucleon fluctuations in small systems. In this paper, we employ the hybrid model iEBE-VISHNU with Trento initial conditions to study the collective flow and the fluid behavior in p/d/${}^3$He+Au collisions. With fine-tuned parameters, iEBE-VISHNU can describe the $v_2(p_T)$ and $v_3(p_T)$ data from the PHENIX and STAR collaborations. However, for some certain parameter sets with initial sub-nucleon fluctuation, the hydrodynamic simulations have already beyond their limits with the average Knudsen number $⟨K_n⟩$ obviously larger than one. Our calculations demonstrate that, for a meaningful evaluation of the fluid behavior in the small systems, model simulations should also pay attention to the validity range of hydrodynamics.

   ↳ nucl-thhep-phnucl-exCPC(2024)·6 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.