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Nuclear Theory·nucl-th

Tuesday·March 14, 2023

10 papers—7 primary·3 cross-listed

All10Primary7Cross-lists3
  1. 08

    The study of r-process nucleosynthesis in binary neutron star mergers: Nucleonic weak interactions and nuclear uncertainties

    Ina K. B. Kullmann🇺🇸

    A long-standing scientific puzzle has been to explain the origin of the heaviest elements in the Universe and, more particularly, the production of the elements heavier than iron up to uranium. The rapid neutron capture process (or r-process) is known to synthesize about 50\% of these heavy elements and the long-lived actinides observed in our solar system and so-called metal-poor r-process-enhanced stars. This thesis aims to study the r-process nucleosynthesis and some of the uncertainties that still govern our predictions, namely, nuclear yields and heating rates. Our focus will be on the r-process in neutron star (NS) mergers, which is in the spotlight after recent ``multi-messenger'' observations, including the combined detection of gravitational waves from a NS-NS merger event and its subsequent electromagnetic counterpart. In this work, we base our nucleosynthesis calculations on hydrodynamical simulations of NS merger systems, which estimate the amount of ejected mass and its properties during ejection. Through our r-process calculations, we estimate the composition of this gravitationally unbound material, which can contribute to the r-process enrichment of the Galaxy. This work is divided into two studies, each addressing a remaining open question regarding the r-process nucleosynthesis. First, a coherent study of the impact of neutrino interactions on the r-process element nucleosynthesis and the heating rate produced by the radioactive decay of nuclei synthesized in the dynamical ejecta of NS-NS mergers is presented. We have studied the material ejected from four NS-NS merger systems based on hydrodynamical simulations...

    ↳ astro-ph.HEnucl-thhttps://difusion.ulb.ac.be/vufind/Record/…·0 citations
  2. 09

    High energy nuclear physics meets Machine Learning

    Wan-Bing He🇨🇳 · Yu-Gang Ma🇨🇳 · Long-Gang Pang🇨🇳 · Huichao Song🇨🇳 · Kai Zhou🇩🇪

    Though being seemingly disparate and with relatively new intersection, high energy nuclear physics and machine learning have already begun to merge and yield interesting results during the last few years. It's worthy to raise the profile of utilizing this novel mindset from machine learning in high energy nuclear physics, to help more interested readers see the breadth of activities around this intersection. The aim of this mini-review is to introduce to the community the current status and report an overview of applying machine learning for high energy nuclear physics, to present from different aspects and examples how scientific questions involved in high energy nuclear physics can be tackled using machine learning.

    ↳ hep-phhep-exnucl-exnucl-thNucl.Sci.Tech.(2023)·105 citations
  3. 10

    Compositeness of and by considering decay and coupled-channels effects

    Tomona Kinugawa🇯🇵 · Tetsuo Hyodo🇯🇵

    The compositeness of weakly bound states is discussed using the effective field theory from the viewpoint of the low-energy universality. We introduce a model with coupling of the single-channel scattering to the bare state, and study the compositeness of the bound state by varying the bare state energy. In contrast to the naive expectation that the near-threshold states are dominated by the molecular structure, we demonstrate that a non-composite state can always be realized even with a small binding energy. At the same time, however, it is shown that a fine tuning is necessary to obtain the non-composite weakly bound state. In other words, the probability of finding a model with the composite dominant state becomes larger with the decrease of the binding energy in accordance with the low-energy universality. For the application to exotic hadrons, we then discuss the modification of the compositeness due to the decay and coupled-channels effects. We quantitatively show that these contributions suppress the compositeness, because of the increase of the fraction of other components. Finally, as examples of near-threshold exotic hadrons, the structures of and are studied by evaluating the compositeness. We find the importance of the coupled-channels and decay contributions for the structures of and , respectively.

    ↳ hep-phnucl-thPRC(2024)·38 citations

Affiliations

first authorsco-authorsvia INSPIRE