Nuclear Theory·nucl-th

Monday·May 29, 2023

8 papers—3 primary·5 cross-listed

01
Machine learning transforms the inference of the nuclear equation of state
Yongjia Wang · Qingfeng Li
Our knowledge of the properties of dense nuclear matter is usually obtained indirectly via nuclear experiments, astrophysical observations, and nuclear theory calculations. Advancing our understanding of the nuclear equation of state (EOS, which is one of the most important properties and of central interest in nuclear physics) has relied on various data produced from experiments and calculations. We review how machine learning is revolutionizing the way we extract EOS from these data, and summarize the challenges and opportunities that come with the use of machine learning.
nucl-thnucl-exFront.Phys.(Beijing)(2023)·21 citations
02
The Fate of excited state of $^{4} He$
Mario Gattobigio🇫🇷 · Alejandro Kievsky🇮🇹
We investigate the properties of the excited state of $^{4} He$ , $^{4} He^{*}$ , within the framework of Efimov physics and its connection to the unitary point of the nuclear interaction. We explore two different approaches to track the trajectory of $^{4} He^{*}$ as it crosses the $^{3} H$ +p threshold and potentially becomes a resonant state. The first approach involves an analytical continuation of the energy with respect to the Coulomb coupling, while the second approach introduces an artificial four-body force that it is gradually released. By utilizing Padé approximants and extrapolation techniques, we estimate the energy and width of the resonance. Our results suggest a central energy value of $E_{R} = 0.060 (3)$ MeV and a width of $Γ/2 = 0.036 (6)$ MeV using the Coulomb analysis, and $E_{R} = 0.068 (1)$ MeV and $Γ/2 = 0.007 (5)$ MeV with the four-body force analysis. Interestingly, these results are consistent with calculations based on {\it ab-initio} nuclear interactions but differ from the accepted values of the $0^{+}$ resonance energy and width. This highlights the challenges in accurately determining the properties of resonant states in light nuclei and calls for further investigations and refinements in theoretical approaches.
nucl-thphysics.atm-clusFew Body Syst.(2023)·8 citations
03
Impact of initial fluctuations and nuclear deformations in isobar collisions
Jian-fei Wang🇨🇳 · Hao-jie Xu🇨🇳 · Fuqiang Wang🇨🇳
Relativistic isobar ( $_{44}^{96}$ Ru+ $_{44}^{96}$ Ru and $_{40}^{96}$ Zr+ $_{40}^{96}$ Zr) collisions have revealed intricate differences in their nuclear size and shape, inspiring unconventional studies of nuclear structure using relativistic heavy ion collisions. In this study, we investigate the relative differences in the mean multiplicity ( $R_{⟨ N_{ch} ⟩}$ ) and the second- ( $R_{ϵ_{2}}$ ) and third-order eccentricity ( $R_{ϵ_{3}}$ ) between isobar collisions using initial state models. It is found that initial fluctuations and nuclear deformations have negligible effects on $R_{⟨ N_{ch} ⟩}$ in most central collisions, while both are important for the $R_{ϵ_{2}}$ and $R_{ϵ_{3}}$ , the degree of which is sensitive to the underlying nucleonic or sub-nucleonic degree of freedom. These features, compared to real data, may probe the particle production mechanism and the physics underlying nuclear structure.
nucl-thnucl-exNucl.Sci.Tech.(2024)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE

Machine learning transforms the inference of the nuclear equation of state

The Fate of excited state of 4He

Impact of initial fluctuations and nuclear deformations in isobar collisions

Affiliations

The Fate of excited state of $^{4} He$