Nuclear Theory·nucl-th

Tuesday·November 30, 2021

27 papers—14 primary·13 cross-listed

01
[Submitted on 26 Nov 2021]
Pairing effects in nuclear pasta phase within the relativistic Thomas-Fermi formalism
U. J. Furtado · S. S. Avancini · J. R. Marinelli
Pairing effects in non-uniform nuclear matter, surrounded by electrons, are studied in the protoneutron star early stage and in other conditions. The so-called nuclear pasta phases at subsaturation densities are solved in a Wigner-Seitz cell, within the Thomas-Fermi approximation. The solution of this problem is important for the understanding of the physics of a newly born neutron star after a supernova explosion. It is shown that the pasta phase is more stable than uniform nuclear matter on some conditions and the pairing force relevance is studied in the determination of these stable phases.
Comments:
23 pages, 11 figures. Accepted for publication in J. of Physics G: Nucl. and Part. Physics
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2111.13771 [pdf]
J.Phys.G(2022)·7 citations
02
[Submitted on 27 Nov 2021]
Hidden charm mesons in nuclear matter and nuclei
J.J. Cobos-Martínez🇲🇽 · K. Tsushima🇧🇷 · G. Krein🇧🇷 · A.W. Thomas🇦🇺
Recent results for the $η_{c}$ - and $J / ψ$ -nucleus bound state energies for various nuclei are presented. The attractive potentials for the $η_{c}$ and $J / ψ$ mesons in the nuclear medium originate, respectively, from the in-medium enhanced $D D^{*}$ and $D D ˉ$ loops in the $η_{c}$ and $J / ψ$ self energies. Our results suggest that the $η_{c}$ and $J / ψ$ mesons should form bound states with all the nuclei considered.
Comments:
Contribution to the proceedings of the 22nd Particles and Nuclei International Conference (PANIC 2021), 5 pages, 2 figures, and 1 table. arXiv admin note: text overlap with arXiv:2109.10995
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2111.13820 [pdf]
PoS(2022)·2 citations
03
[Submitted on 27 Nov 2021]
Semi-analytical calculation of the trajectory of relativistic nuclear collisions in the QCD phase diagram
Todd Mendenhall🇺🇸 · Zi-Wei Lin🇺🇸
We extend a semi-analytical model that includes the finite nuclear thickness to calculate the energy density $ϵ (t)$ and conserved-charge densities including the net-baryon density $n_{_{B}} (t)$ produced at mid-spacetime-rapidity in central Au+Au collisions. Assuming the formation of a quark-gluon plasma with an ideal gas equation of state of either quantum or Boltzmann statistics or with a lattice QCD-based equation of state, we extract the temperature $T$ and chemical potentials $μ_{_{B}}$ , $μ_{_{Q}}$ and $μ_{_{S}}$ as functions of time. This then allows us to semi-analytically calculate the $T - μ_{_{B}}$ trajectory of relativistic nuclear collisions in the QCD phase diagram, which should benefit the studies of high density physics including the search for the critical end point. This model is also useful for exploring the trajectories in the more general $T - μ_{_{B}} - μ_{_{Q}} - μ_{_{S}}$ QCD phase space.
Comments:
19 pages, 12 figures, corrected typo in Eq.(41) and citations to Figs.11-12
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2111.13932 [pdf]
PRC(2023)·6 citations
04
[Submitted on 27 Nov 2021]
Coupled baryon, electric charge and strangeness fluctuations in heavy-ion collisions
Grégoire Pihan🇫🇷 · Marcus Bluhm🇫🇷 · Marlene Nahrgang🇫🇷
We present for the first time quantitative results for the coupled dynamics of second order fluctuations in the three conserved charges of QCD based on stochastic diffusion equations for a Bjorken-type expanding hadronic medium.
Comments:
Proceedings for the 19th International Conference on Strangeness in Quark Matter (SQM 2021), May 17-22, 2021, online
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2111.13977 [pdf]
EPJ Web Conf.(2022)·1 citation
05
[Submitted on 28 Nov 2021]
Momentum dependence of near-threshold photoproduction of $Ξ^{-}$ hyperons off nuclei and their properties in the nuclear medium
E. Ya. Paryev🇷🇺
We study the near-threshold inclusive photoproduction of $Ξ^{-}$ hyperons off $^{12}$ C and $^{184}$ W target nuclei within a first-collision model relying on the nuclear spectral function and including incoherent $Ξ^{-}$ production in direct elementary $γ p \to K^{+} K^{+} Ξ^{-}$ and $γ n \to K^{+} K^{0} Ξ^{-}$ processes. The model takes into account the impact of the nuclear effective scalar $K^{+}$ , $K^{0}$ , $Ξ^{-}$ and their Coulomb potentials on these processes as well as the absorption of final $Ξ^{-}$ hyperons in nuclear matter, the binding of intranuclear nucleons and their Fermi motion. We calculate the absolute differential cross sections and their ratios for the production of $Ξ^{-}$ hyperons off these nuclei at laboratory polar angles $\leq$ 45 $^{\circ}$ by photons with energies of 2.5 and 3.0 GeV, with and without imposing the phase space constraints on the $Ξ^{-}$ emission angle in the respective $γ p$ center-of-mass system. We also calculate the momentum dependence of the transparency ratio for $Ξ^{-}$ hyperons for the $^{184}$ W/ $^{12}$ C combination at these photon energies. We show that the $Ξ^{-}$ momentum distributions (absolute and relative) at the adopted initial photon energies possess, contrary to the transparency ratio for $Ξ^{-}$ hyperons, a definite sensitivity to the considered changes in the scalar $Ξ^{-}$ nuclear mean-field potential at saturation density $ρ_{0}$ in the low-momentum range of 0.1--0.8 GeV/c. Therefore, the precise measurements of these distributions in a dedicated experiment at the CEBAF facility will provide valuable information on the $Ξ^{-}$ in-medium properties, which will be supplementary to that inferred from studying of the ( $K^{-}$ , $K^{+}$ ) reactions at initial momenta of 1.6--1.8 GeV/c.
Comments:
25 pages, 14 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2111.14101 [pdf]
NPA(2022)·2 citations
06
[Submitted on 28 Nov 2021]
Bayesian Data Fusion of Imperfect Fission Yields for Augmented Evaluations
Z.A. Wang · J.C. Pei · Y.J. Chen · C.Y. Qiao · F.R. Xu · Z.G. Ge · N.C. Shu
We demonstrate that Bayesian machine learning can be used to treat the vast amount of experimental fission data which are noisy, incomplete, discrepant, and correlated. As an example, the two-dimensional cumulative fission yields (CFY) of neutron-induced fission of $^{238}$ U are evaluated with energy dependencies and uncertainty qualifications. For independent fission yields (IFY) with very few experimental data, the heterogeneous data fusion of CFY and IFY is employed to interpolate the energy dependence. This work shows that Bayesian data fusion can facilitate the further utilization of imperfect raw nuclear data.
Comments:
5 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2111.14102 [pdf]
PRC(2022)·16 citations
07
[Submitted on 28 Nov 2021]
Appearance of peak in symmetry energy at N = 126 for Pb isotopic chain within relativistic energy density functional
Jeet Amrit Pattnaik · T. M. Joshua · Ankit Kumar · M. Bhuyan · S. K. Patra
The newly derived relativistic energy density functional [\textcolor{blue}{ Phys. Rev. C \textbf{103}, 024305 (2021)}], which stems from the effective field theory motivated relativistic mean-field (E-RMF) is employed to establish the appearance of peak/kink in the symmetry energy over the isotopic chain of Pb-nuclei. The coherent density fluctuation model parametrization procedure for finite nuclei is adopted here to obtain the relativistic energy density functional at local density. The relativistic energy density functional from E-RMFT takes precedence over the Brückner energy density functional as it accurately predicts the empirical saturation density and binding energy per nucleon $E / A$ , so-called 'Coester Band Problem'. Interestingly, using the relativistic energy density functional, it is possible to predict the peak at $N = 126$ for recently developed G3 and widely used NL3 parameter sets, which is not observed for Brückener's functional in-spite of using the E-RMF density. From the present analysis, the newly fitted energy density functional is found to be minutely sensitive to the choice of the parameter sets employed.
Comments:
4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2111.14113 [pdf]
PRC(2022)·14 citations
08
[Submitted on 28 Nov 2021]
Systematic study of two-proton radioactivity half-lives based on a modified Gamow-like model
Hong-Ming Liu · You-Tian Zou · Xiao Pan · Biao He · Xiao-Hua Li
In the present work, we systematically study the two-proton (2p) radioactivity half-lives of nuclei close to the proton drip line within a modified Gamow-like model. Using this model, the calculated 2p radioactivity half-lives can well reproduce the experimental data. Moreover, we use this model to predict the 2p radioactivity half-lives of 22 candidates whose 2p radioactivity is energetically allowed or observed but not yet quantied in evaluated nuclear properties table NUBASE2016. The predicted results are in good agreement with the ones obtained by using Gamow-like model, effective liquid drop model (ELDM), generalized liquid drop model (GLDM) as well as a four-parameter formula.
Comments:
12 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2111.14115 [pdf]
IJMPE(2021)·14 citations
09
[Submitted on 28 Nov 2021]
A Pfaffian formulation for matrix elements of three-body operators in multiple quasi-particle configurations
Zi-Rui Chen · Long-Jun Wang
We present a Pfaffian formula to calculate matrix elements of three-body operators in symmetry-restoration beyond-mean-field methods, including the case of multiple quasi-particle configurations. Detailed derivation based on [Mizusaki et al., Phys. Lett. B 715, 219 (2012)] and [Hu et al., Phys. Lett. B 734, 162 (2014)] is provided, and potential applications in generator coordinate method with chiral interactions, as well as in study of nuclear matrix elements in neutrinoless double beta decay are discussed.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2111.14133 [pdf]
PRC(2022)·11 citations
10
[Submitted on 28 Nov 2021]
Perturbative quantum Monte Carlo method for nuclear physics
Bing-Nan Lu🇨🇳 · Ning Li🇨🇳 · Serdar Elhatisari🇹🇷 · Yuan-Zhuo Ma🇨🇳 · Dean Lee🇺🇸 · Ulf-G. Meißner🇩🇪
While first order perturbation theory is routinely used in quantum Monte Carlo (QMC) calculations, higher-order terms present significant numerical challenges. We present a new approach for computing perturbative corrections in projection QMC calculations. We demonstrate the method by computing nuclear ground state energies up to second order for a realistic chiral interaction. We calculate the binding energies of several light nuclei up to $^{16}$ O by expanding the Hamiltonian around the Wigner SU(4) limit and find good agreement with data. In contrast to the natural ordering of the perturbative series, we find remarkably large second order energy corrections. This occurs because the perturbing interactions break the symmetries of the unperturbed Hamiltonian. Our method is free from the sign problem and can be applied to QMC calculations for many-body systems in nuclear physics, condensed matter physics, ultracold atoms, and quantum chemistry.
Comments:
5 pages main text, 6 pages supplemental material, more details on the perturbative expansion, version accepted for publication in Phys. Rev. Lett
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Lattice (hep-lat)
arXiv:
2111.14191 [pdf]
PRL(2022)·48 citations
11
[Submitted on 29 Nov 2021]
Description of $^{93}$ Nb stellar electron-capture rates by the Projected Shell Model
Long-Jun Wang · Liang Tan · Zhipan Li · Bingshui Gao · Yang Sun
Capture of electrons by nuclei is an important process in stellar environments where excited nuclear states are thermally populated. However, accurate treatment for excited configurations in electron capture (EC) rates has been an unsolved problem for medium-heavy and heavy nuclei. In this work, we take the $^{93}$ Nb $\to$ $^{93}$ Zr EC rates as the example to introduce the Projected-Shell-Model (PSM) in which excited configurations are explicitly included as multi-quasiparticle states. Applying the prevalent assumption that the parent nucleus always stays in its ground state in stellar conditions, we critically compare the obtained PSM results with the recently-measured Gamow-Teller transition data, and with the previous calculations by the conventional shell model and the quasiparticle random-phase approximation. We discuss important ingredients that are required in theoretical models used for stellar EC calculations, and demonstrate effects of the explicit inclusion of excited nuclear states in EC rate calculations, especially when both electron density and environment temperature are high.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2111.14288 [pdf]
PRC(2021)·10 citations
12
[Submitted on 29 Nov 2021]
Competition between diffusion and rapid expansion and its impact on critical fluctuations in heavy-ion collisions
Grégoire Pihan · Marcus Bluhm · Masakiyo Kitazawa · Marlene Nahrgang
We study the impact of the competition between the expansion of the medium created in heavy-ion collisions and its diffusive properties on the critical fluctuations of the net-baryon density. As the relaxation time of the fluctuations is connected with the diffusive properties, the latter determine the in- or out-of-equilibrium nature of the net-baryon density fluctuations during the fireball evolution. This may result in important consequences for the phenomenological interpretation of heavy-ion collision data. We study three possible situations that can occur as a result of the competition between diffusion and expansion and discuss the impact of this competition on the integrated second and fourth order cumulants of net-baryon density fluctuations at freeze-out in these situations.
Comments:
Proceedings for the the International conference on Critical Point and Onset of Deconfinement (CPOD 2021), March 15-19, 2021, online
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2111.14466 [pdf]
PoS(2022)·0 citations
13
[Submitted on 29 Nov 2021]
Off-equilibrium non-Gaussian fluctuations near the QCD critical point: an effective field theory perspective
Noriyuki Sogabe🇨🇳 · Yi Yin🇨🇳
The non-Gaussian fluctuations of baryon density are sensitive to the presence of the conjectured QCD critical point. Their observational consequences are crucial for the ongoing experimental search for this critical point through the beam energy scan program at Relativistic Heavy Ion Collider (RHIC). In the expanding fireball created in a heavy-ion collision, critical fluctuations would inescapably fall out of equilibrium, and require a systematic description within a dynamical framework. In this paper, we employ newly developed effective field theory (EFT) for fluctuating hydrodynamics to study the real-time critical non-Gaussian fluctuations of a conserved charge density. In particular, we derive the evolution equations for multi-point correlators of density fluctuations and obtain the closed-form solutions with arbitrary initial conditions that can readily be implemented in realistic simulations for heavy-ion collisions. We find that non-linear interactions among noise fields, which are missing in traditional stochastic hydrodynamics, could potentially contribute to the quartic (fourth order) fluctuations in scaling regime even at tree level in off-equilibrium situations.
Comments:
25 pages
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
arXiv:
2111.14667 [pdf]
JHEP(2022)·17 citations
14
[Submitted on 29 Nov 2021]
Probing nuclear structure with mean transverse momentum in relativistic isobar collisions
Hao-jie Xu🇨🇳 · Wenbin Zhao🇺🇸 · Hanlin Li🇨🇳 · Ying Zhou🇨🇳 · Lie-Wen Chen🇨🇳 · Fuqiang Wang🇨🇳
Transverse momentum ( $p_{T}$ ) generation in relativistic heavy ion collisions is sensitive to the initial geometry and the final-state bulk evolution. We demonstrate with hydrodynamic calculations that the mean $p_{T}$ ratio ( $R_{⟨ p_{T} ⟩}$ ) between the highly similar isobar $_{44}^{96}$ Ru+ $_{44}^{96}$ Ru and $_{40}^{96}$ Zr+ $_{40}^{96}$ Zr collisions is insensitive to the bulk evolution and remains sensitive to the small difference in the initial nuclear structure (neutron skin and deformation) between the Ru and Zr nuclei.We further find that nuclear deformation can produce an anticorrelation between $R_{⟨ p_{T} ⟩}$ and eccentricity (or elliptic flow) in central collisions. These findings suggest that the $R_{⟨ p_{T} ⟩}$ between the isobar systems can be used to measure the neutron skin thickness and deformation parameters, which can in turn constrain the nuclear symmetry energy slope parameter.
Comments:
6 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2111.14812 [pdf]
PRC(2023)·80 citations

Affiliations

first authorsco-authorsvia INSPIRE