Nuclear Theory·nucl-th

Monday·May 5, 2025

11 papers—8 primary·3 cross-listed

01
[Submitted on 1 May 2025]
Connecting Relativistic Density Functional Theory to Microscopic Calculations
Brendan T. Reed🇺🇸 · Matthias Heinz🇺🇸 · Pierre Arthuis🇫🇷 · Achim Schwenk🇩🇪 · Ingo Tews🇺🇸
The development of systematic effective field theories (EFTs) for nuclear forces and advances in solving the nuclear many-body problem have greatly improved our understanding of dense nuclear matter and the structure of finite nuclei. For global nuclear calculations, density functional theories (DFTs) have been developed to reduce the complexity and computational cost required in describing nuclear systems. However, DFT often makes approximations and assumptions about terms included in the functional, which may introduce systematic uncertainties compared to microscopic calculations using EFTs. In this work, we investigate possible avenues of improving nuclear DFT using nonlinear relativistic mean-field (RMF) theory. We explore the impact of RMF model extensions by fitting the nonlinear RMF model to predictions of nuclear matter and selected closed-shell nuclei using four successful chiral EFT Hamiltonians. We find that these model extensions are impactful and important in capturing the physics present within chiral Hamiltonians, particularly for charge radii and neutron skins of closed-shell nuclei. However, there are additional effects that are not captured within the RMF model, particularly within the isoscalar sector of RMF theory. Additional model extensions and the reliability of the nonlinear RMF model are discussed.
Comments:
19 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.00828 [pdf]
PRC(2025)·8 citations
02
[Submitted on 1 May 2025]
Bayesian inferences on covariant density functionals from multimessenger astrophysical data: The impacts of likelihood functions of low density matter constraints
Jia-Jie Li🇨🇳 · Armen Sedrakian🇩🇪
We systematically investigate how the choice between Gaussian and uniform likelihood functions in Bayesian inference affects the inferred bulk properties of compact stars and nuclear matter within covariant density functional-based equations of state. To enable direct comparison between the two approaches, we designed the uniform likelihood function with a Gaussian-equivalent normalization factor and marginalization behavior. Across three representative astrophysical scenarios, both approaches yield nearly identical mass-radius relations, density-pressure relations, and overlapping 95.4\% confidence level regions. Although our inference analysis is carried out using parameters of the density functional, we subsequently determine the associated nuclear matter characteristic coefficients derived from the Taylor expansion of the energy density around the saturation density. We observe significant variation in the predicted isoscalar channel coefficients (e.g., the nuclear incompressibility) across different astrophysical scenarios, while the isovector channel (e.g., the slope of symmetry energy) exhibits only minimal variation.
Comments:
15 pages, 6 figures, matches published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.00911 [pdf]
PRC(2025)·10 citations
03
[Submitted on 2 May 2025]
Expanded calculations of pn-QRPA electron capture rates on $^{55}$ Co for presupernova and supernova physics
Jameel-Un Nabi · Muhammad Sajjad
Due to its abundance and its relatively high capture rates, $^{55}$ Co is one of the key nuclide that can control the dynamics of core collapse of a massive star. Previously we introduced our microscopic calculations of capture rates on $^{55}$ Co using the proton-neutron quasi-particle random phase approximation (pn-QRPA) theory. Here we present for the first time an expanded calculation of the electron capture rates on $^{55}$ Co on an extensive temperature-density scale. These type of scale is appropriate for interpolation purposes and of greater utility for simulation codes.
Comments:
20 pages, 2 Figures, 3 Tables. arXiv admin note: substantial text overlap with arXiv:1108.0826
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.01024 [pdf]
Can.J.Phys.(2008)·1 citation
04
[Submitted on 2 May 2025]
Study of electron capture rates on chromium isotopes for core-collapse simulations
Muhammad Majid · Jameel-Un Nabi
Electron capture rates on \emph{fp}-shell nuclei play a pivotal role in the dynamics of stellar evolution and core collapse. These rates play a crucial role in the gravitational collapse of the core of a massive star activating the supernova explosion. As per simulation results, capture rates on chromium isotopes have a major impact on controlling the lepton-to-baryon fraction of the stellar core during the late phases of evolution of massive stars. In this paper we calculate the electron capture rates on isotopes of chromium with mass range $42 \leq A \leq 65$ , including neutron-deficient and neutron-rich isotopes. For the calculation of weak rates in stellar matter, we used the pn-QRPA model with separable Gamow-Teller forces and took deformation of nucleus into consideration. A recent study proved this form of pn-QRPA to be the best for calculation of GT strength distributions amongst the pn-QRPA models. The stellar weak rates are calculated over a broad range of temperature $(0.01 \times 1 0^{9} - 30 \times 1 0^{9} (K))$ and density $(10 - 1 0^{11} (g / c m^{3}))$ domain. We compare our electron capture rates with the pioneering calculation of Fuller, Fowler, and Newman (FFN) and with the large-scale shell model (LSSM) calculation. Our electron capture rates are enhanced compared to the FFN and shell model rates.
Comments:
20 Pages , 4 Tables, 5 Figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.01025 [pdf]
Rom.Rep.Phys.(2016)·4 citations
05
[Submitted on 2 May 2025]
Gamma Ray Heating and Neutrino Cooling Rates due to Weak Interaction Processes on sd-shell Nuclei in Stellar Cores
Muhammad Fayaz · Jameel-Un Nabi · Muhammad Majid
Gamma ray heating and neutrino cooling rates, due to weak interaction processes, on $s d$ -shell nuclei in stellar core are calculated using the proton neutron quasiparticle random phase approximation theory. The recent extensive experimental mass compilation of \citep{Wang12}, other improved model input parameters including nuclear quadrupole deformation \citep{Ram01}, \citep{Mol16} and physical constants are taken into account in the current calculation. The purpose of this work is two fold, one is to improve the earlier calculation of weak rates performed by \citep{Nabi99} using the same theory. We further compare our results with previous calculations. The selected $s d$ -shell nuclei, considered in this work, are of special interest for the evolution of O-Ne-Mg core in 8-10 M $_{⊙}$ stars due to competitive gamma ray heating rates and cooling by URCA processes. The outcome of these competitions is to determine, whether the stars end up as a white dwarf \citep{Nabi08}, an electron-capture supernova \citep{Jones13} or Fe core-collapse supernova \citep{Suz16}. The selected $s d$ -shell nuclei for calculation of associated weak-interaction rates include $^{20, 23}$ O, $^{20, 23}$ F, $^{20, 23, 24}$ Ne, $^{20, 23 - 25}$ Na, and $^{23 - 25}$ Mg. The cooling and heating rates are calculated for density range ( $10 \leq ρ ($ \;g.cm $^{- 3}) \leq$ 10 $^{11}$ ) and temperature range ( $0.01 \times 1 0^{9}$ $\leq$ $T (K)$ $\leq$ $30 \times 1 0^{9}$ ). The calculated gamma heating rates are orders of magnitude bigger than the shell model rates (except for $^{25}$ Mg at low densities). At high temperatures the gamma heating rates are in reasonable agreement. The calculated cooling rates are up to an order of magnitude bigger for odd-A nuclei.
Comments:
25 Pages, 13 Tables, 6 Figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.01029 [pdf]
Astrophys.Space Sci.(2017)·23 citations
06
[Submitted on 2 May 2025]
Nuclear structure study using a hybrid approach of shell model and Gogny-type density functionals
Kota Yoshinaga · Noritaka Shimizu · Takashi Nakatsukasa
Nuclear density functional theory (DFT) is able to reproduce the saturation properties of nuclear matter, as well as properties of finite nuclei. Consequently, the DFT calculations are applicable to nuclei across a wide range of masses on nuclear chart. The Gogny-type density functional, which is equivalent to the mean-field calculations with finite-range density-dependent effective interactions, is a successful example. In contrast, the shell-model (configuration-interaction) calculation is a powerful tool to describe nuclear structure, especially spectroscopic properties. The shell model is able to take into account correlations beyond mean field in a truncated model space. In this work, we report investigation on $sd$ -shell nuclei and Ca isotopes using a hybrid approach of the shell model and Gogny-type DFT.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.01072 [pdf]
Particles(2025)·1 citation
07
[Submitted on 2 May 2025]
Effect of the Coulomb interaction on nuclear deformation and drip lines
Kenta Hagihara · Takashi Nakatsukasa · Nobuo Hinohara
Nuclei are self-bound systems in which the strong interaction (nuclear force) plays a dominant role and the isospin is approximately a good quantum number. The isospin symmetry is primarily violated by the electromagnetic interactions, namely the Coulomb interaction among protons, effects of which need be studied to understand importance of the isospin symmetry. We investigate the effect of the Coulomb interaction on nuclear properties, especially the quadrupole deformation and neutron drip line, utilizing the density functional method which provides a universal description of nuclear systems in the entire nuclear chart. We carry out calculations of even-even nuclei with the proton number 2 to 60. The results show that the Coulomb interaction plays a significant role in enhancing the quadrupole deformation across a wide range of nuclei. We also find that nuclei near the neutron drip line gain an additional binding energy by the Coulomb interaction, which may lead to a shift of the neutron drip line toward a larger neutron number.
Comments:
8 pages, 5figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.01211 [pdf]
Particles(2025)·0 citations
08
[Submitted on 2 May 2025]
Deblurring fission fragment mass distributions
Pierre Nzabahimana · Amy E. Lovell · Patrick Talou
Measurements of fission fragment mass distributions provide valuable insights into the properties of fissioning systems and the dynamics of the fission process. Pre-neutron emission distributions, essential for fission fragment evaporation codes like \cgmf{}, are extracted from distributions that are always measured after neutron emission, as the time scale of the emission of prompt fission neutrons is too short for direct measurement before the emission. However, obtaining accurate pre-neutron emission distributions requires methods that eliminate the effects of mass resolution and detector efficiency. We propose a deblurring technique based on the Richardson-Lucy (RL) algorithm, commonly used in optics for image restoration, to correct for these experimental effects. The RL algorithm uses the measured mass distributions and a transfer matrix to perform iterative deconvolution. The advantage of this method over others is that it does not assume any predefined shape such as a sum of Gaussians, as in \cgmf{}, for the distributions. In this paper, we apply the algorithm to the fission fragment mass distributions measured in the spontaneous fission of $^{252}$ Cf to extract pre-neutron emission fission fragment mass distributions. The results from deblurring are then used as inputs to \cgmf{}, and we compare the \cgmf{} results obtained using deblurring inputs with the default \cgmf{} results.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2505.01294 [pdf]
PRC(2025)·1 citation
09
[Submitted on 1 May 2025] (cross-list from hep-ph)
Study of electron-positron annihilation into four pions within chiral effective field theory in the low energy region
Jia-Yu Zhou🇨🇳 · Hao-Xiang Pan🇨🇳 · Ling-Yun Dai🇨🇳
In this paper, we employ chiral effective field theory to study the process of electron-positron annihilation into four pions in the low energy region within $E_{c . m .} \leq 0.6$ GeV. The prediction of the cross section is obtained through $S U (3)$ chiral perturbation theory up to the next-to-leading order, which is smaller than the experimental data in the energy region [0.6-0.65] GeV, though the data has only a few points and poor statistics. Then, the resonance chiral theory is applied to include the resonance contribution, with the lightest scalars and vectors written in the effective Lagrangians. A series of relevant decay widths and the masses of the vectors are studied to fix the unknown couplings. The resonance contribution should be one order larger than that of the chiral perturbation theory but still one to two orders smaller than the data. The significant discrepancy urged the new experimental measurements to give more guidance. We also compute the leading order hadronic vacuum polarization contribution from the four pion channels to the anomalous magnetic moment of the muon, $(g - 2)_{μ}$ . In the energy range from threshold up to 0.6 GeV within resonance chiral theory, the contributions are $a_{μ} = (0.680 \pm 0.062) \times 1 0^{- 16}$ and $a_{μ} = (0.597 \pm 0.058) \times 1 0^{- 16}$ for the processes of $e^{+} e^{-} \to π^{+} π^{+} π^{-} π^{-}$ , $π^{0} π^{0} π^{+} π^{-}$ , respectively.
Comments:
23 pages, 8 figures, to be the same as the published version and correct a few typos
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2505.00770 [pdf]
PRD(2026)·2 citations
10
[Submitted on 1 May 2025] (cross-list from hep-ph)
Holographic Heavy Quark Energy Loss in the Hybrid Model
Jean F. Du Plessis🇺🇸 · Daniel Pablos🇪🇸 · Krishna Rajagopal🇺🇸
To date, holographic calculations in strongly coupled plasma have provided separate descriptions for the rates of energy loss either for ultrarelativistic massless quarks and gluons or for infinitely massive quarks, with the latter calculation valid for $γ < M / (λ T)$ , where $γ$ is the Lorentz boost factor for a heavy quark with velocity $v$ and mass $M$ moving through plasma with 't Hooft coupling $λ$ and temperature $T$ . These two calculations should apply sequentially in the description of the energy loss of a heavy quark that starts out ultrarelativistic, loses energy, slows down, becomes non-relativistic at later times, and ultimately comes to rest and diffuses in the strongly coupled plasma. We provide an ansatz for uniquely incorporating both regimes to give an approximate but unified description of how a heavy quark that is initially ultrarelativistic loses energy all the way until it comes to rest. We implement this ansatz in the Hybrid Strong/Weak Coupling Model. With this new, consistent, treatment of heavy quark energy loss at strong coupling, we confront our predictions for the suppression and azimuthal anisotropies of D- and B-mesons, as well as B-tagged jets, with available experimental data.
Comments:
7 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2505.00863 [pdf]
EPJ Web Conf.(2025)·0 citations
11
[Submitted on 1 May 2025] (cross-list from hep-ph)
Entanglement Maximization and Mirror Symmetry in Two-Higgs-Doublet Models
Marcela Carena🇨🇦 · Guglielmo Coloretti🇨🇭 · Wanqiang Liu🇺🇸 · Mira Littmann🇺🇸 · Ian Low🇺🇸 · Carlos E. M. Wagner🇨🇦
We consider 2-to-2 scatterings of Higgs bosons in a CP-conserving two-Higgs-doublet model (2HDM) and study the implication of maximizing the entanglement in the flavor space, where the two doublets $Φ_{a}$ , $a = 1, 2$ , can be viewed as a qubit: $Φ_{1} = ∣0 ⟩$ and $Φ_{2} = ∣1 ⟩$ . More specifically, we compute the scattering amplitudes for $Φ_{a} Φ_{b} \to Φ_{c} Φ_{d}$ and require the outgoing flavor entanglement to be maximal for a full product basis such as the computational basis, which consists of ${∣00 ⟩, ∣01 ⟩, ∣10 ⟩, ∣11 ⟩}$ . In the unbroken phase and turning off the gauge interactions, entanglement maximization results in the appearance of an $U (2) \times U (2)$ global symmetry among the quartic couplings, which in general is broken softly by the mass terms. Interestingly, once the Higgs bosons acquire vacuum expectation values, maximal entanglement enforces an exact $U (2) \times U (2)$ symmetry, which is spontaneously broken to $U (1) \times U (1)$ . As a byproduct, this gives rise to Higgs alignment as well as to the existence of 6 massless Nambu-Goldstone bosons. The $U (2) \times U (2)$ symmetry can be gauged to lift the massless Goldstones, while maintaining maximal entanglement demands the presence of a discrete $Z_{2}$ symmetry interchanging the two gauge sectors. The model is custodially invariant in the scalar sector, and the inclusion of fermions requires a mirror dark sector, related to the standard one by the $Z_{2}$ symmetry.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2505.00873 [pdf]
JHEP(2025)·29 citations

Affiliations

first authorsco-authorsvia INSPIRE