Nuclear Theory·nucl-th

Monday·June 17, 2024

9 papers—7 primary·2 cross-listed

01
[Submitted on 14 Jun 2024]
Spontaneous fission half-life in Fm isotopes with nuclear energy density functional
Kouhei Washiyama
A microscopic description of fission dynamics is important to understand the decay properties of neutron-rich heavy nuclei that are relevant to $r$ -process nucleosynthesis. To provide a reliable and efficient method to evaluate the spontaneous fission half-life, we develop a method, called the constrained Hartree--Fock--Bogoliubov (CHFB) plus local quasiparticle random-phase approximation (LQRPA), to include dynamical residual effects in the collective inertia. With the CHFB + LQRPA, we evaluate the collective potential and the collective inertia along a mass-symmetric fission path in Fm isotopes with the neutron numbers $N = 158$ --164. The obtained LQRPA inertia is much larger than the cranking one that ignores dynamical residual effects and shows a remarkable variation along the fission path. We estimate the fission half-life of the Fm isotopes using the action integral with the obtained collective potential and inertia. A large difference between the fission half-lives obtained with the LQRPA inertia and with the cranking inertia is observed. This indicates the importance of evaluating the collective inertia for estimating the fission half-life.
Comments:
5 pages, 6 figures, to be published in the proceedings of FUSION23
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2406.09735 [pdf]
EPJ Web Conf.(2024)·0 citations
02
[Submitted on 14 Jun 2024]
Exploration on $1 n$ halo nucleus $^{19}$ C from D-RHFB structure to reaction observables
Jia-Lin An · Qi Lu · Wen Hui Long · Shi-Sheng Zhang
We utilize the axially deformed relativistic Hartree-Fock-Bogoliubov (D-RHFB) model to describe the structure of neutron-rich carbon isotopes, taking into account the continuum, pairing correlations, tensor force and their interplay. In this scheme, one- and two-neutron separation energies of neutron-rich carbon isotopes agree well with measured data, as well as the spin and parity $J^{π} = 1/ 2^{+}$ for the ground state of $^{19}$ C, which is a long-standing problem for theoretical structure models. With the structure input extracted from the microscopic D-RHFB model, the reaction observables are well described the Glauber model. In particular, this unified approach accurately reproduces the inclusive longitudinal momentum distributions of the breakup reaction $^{19}$ C + $^{12}$ C at 240 MeV/nucleon, which rule out the possibility of the ground state of $^{19}$ C being $J^{π} = 3/ 2^{+}$ . Moreover, the continuum plays a crucial role in the formation of the halo, which is further confirmed by the reaction cross sections and longitudinal momentum distributions. However, the tensor force components carried by the $π$ -coupling are not as significant as anticipated. Consequently, the D-RHFB + Glauber approach turns out to be a promising tool to search for halo candidates from the structure to the reaction.
Comments:
The description on the reactions on the carbon target needs more works
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2406.09766 [pdf]
J.Phys.G(2025)·3 citations
03
[Submitted on 14 Jun 2024]
Triaxial shape of the one-proton emitter $^{149}$ Lu
Qi Lu · Kai-Yuan Zhang · Shi-Sheng Zhang
We revisit the proton emitter $^{149}$ Lu utilizing the recently developed triaxial relativistic Hartree-Bogoliubov theory in continuum (TRHBc). By incorporating the microscopic nuclear structure properties from the TRHBc theory into the WKB approximation, we successfully reproduce the measured proton-emission half-life of $^{149}$ Lu within experimental uncertainties. A triaxial ground state characterized by ( $β = 0.17, γ = 3 1^{\circ}$ ) has been clarified for $^{149}$ Lu. The inclusion of triaxiality significantly changes nuclear density distributions and potentials, which results in enhanced binding of both the nuclear system and the proton-emitting orbital. As a result, a slightly extended half-life for the proton emission of $^{149}$ Lu is achieved after considering triaxial deformation degrees of freedom.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2406.09803 [pdf]
PLB(2024)·18 citations
04
[Submitted on 14 Jun 2024]
The weak magnetic field effect on dilepton polarization in heavy-ion collisions
Minghua Wei🇨🇳 · Li Yan🇨🇳
The measurement of the magnetic field created in high-energy heavy-ion collisions is challenging, due the the fact that the magnetic field decays so drastically that in a thermalized quark-gluon plasma the field strength becomes rather weak. By incorporating the weak magnetic effect into the medium, and especially into the production formalism of dileptons from the quark-gluon plasma, the effect of dilepton polarization is studied through the dilepton angular distribution. We find that the anisotropic coefficients in the dilepton spectrum are quite sensitive to the orientation and strength of the weak field. Accordingly, these coefficients provide ideal probes for the magnetic field in realistic experiments.
Comments:
13 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2406.10041 [pdf]
PRD(2024)·8 citations
05
[Submitted on 14 Jun 2024]
Weak entanglement approximation for nuclear structure
Oliver C. Gorton · Calvin W. Johnson
The interacting shell model, a configuration-interaction method, is a venerable approach for low-lying nuclear structure calculations; but it is hampered by the exponential growth of its basis dimension as one increases the single-particle space and/or the number of active particles. Recent, quantum-information-inspired work has demonstrated that the proton and neutron sectors of a nuclear wave function are weakly entangled. Furthermore, the entanglement is smaller for nuclides away from $N = Z$ , such as heavy, neutron-rich nuclides. Here we implement a weak entanglement approximation to bipartite configuration-interaction wave functions, approximating low-lying levels by coupling a relatively small number of many-proton and many-neutron states. This truncation scheme, which we present in the context of past approaches, reduces the basis dimension by many orders of magnitude while preserving essential features of nuclear spectra.
Comments:
11 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2406.10120 [pdf]
PRC(2024)·26 citations
06
[Submitted on 14 Jun 2024]
Investigating the Role of Quantum Entanglement in Heavy Ion Collisions through Elliptic Flow
Mira Varma🇺🇸 · Oliver Baker🇺🇸
This paper investigates the relationship between initial spatial anisotropy and final state momentum anisotropy in heavy ion collisions through the analysis of elliptic flow ( $v_{2}$ ) as a function of transverse momentum ( $p_{T}$ ). Building upon previous studies on thermalization in heavy ion collisions using transverse momentum distributions, we extend the analysis to the $p_{T}$ dependence of $v_{2}$ in Pb-Pb and Xe-Xe collisions. By employing a two-component model to extract the thermal and hard scattering contributions to the elliptic flow, we aim to gain further insights into the role of quantum entanglement in the rapid thermalization and collective behavior of the quark-gluon plasma (QGP).
Comments:
The arXiv version of this paper incorporates additional theoretical context about quantum entanglement in heavy ion collisions based on recent literature. The core contribution is our systematic measurement and analysis of the two-component behavior in elliptic flow across different centralities in Xe-Xe and Pb-Pb collisions. A revised version of this work has been prepared for journal submission
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Quantum Physics (quant-ph)
arXiv:
2406.10129 [pdf]
1 citation
07
[Submitted on 14 Jun 2024]
Study of the Coulomb and nuclear breakup of $^{11}$ Be using a Halo-EFT description at N $^{2}$ LO
L.-P. Kubushishi · P. Capel
Background: The halo effective field theory (Halo-EFT) provides a very efficient description of loosely-bound nuclei in models of reaction. It offers a very systematical ranking of the significance of nuclear-structure observables in reaction calculations. This greatly helps to infer reliable structure information from reaction cross sections. However, for a meaningful analysis, the Halo-EFT scheme needs to have converged. Purpose: In a previous study [P. Capel, D. R. Phillips, and H.-W. Hammer, Phys. Rev. C 98, 034610 (2018)], NLO descriptions of 11Be have been developed and lead to excellent agreement with existing breakup data. However, the convergence of the scheme at NLO was not fully demonstrated. Moreover, a significant dependence on the regulator of the effective 10Be-n interaction has been observed. Method: We develop Halo-EFT descriptions of 11Be at N2LO and use them in an accurate breakup-reaction code. We compare our theoretical cross sections with experiment on Pb and C targets at about 70 MeV/nucleon. Results: On Pb, the N2LO descriptions of 11Be lead to little change to the NLO results of the previous study, confirming the convergence of that scheme. On C, the reaction is significantly affected by the presence of d resonances in the low-energy spectrum of 11Be. In the Halo-EFT power counting these resonances appear only at N2LO; our new descriptions include them naturally. Going to N2LO removes also the cutoff dependence observed in the previous study. Conclusions: We demonstrate the convergence of the Halo-EFT description of 11Be at NLO for Coulomb breakup and at N2LO for nuclear-dominated dissociation. The reliability of the nuclear-structure information inferred in the previous study is thus confirmed.
Comments:
9 pages, 7 figures - This work has been accepted for publication in Physical Review C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2406.10168 [pdf]
PRC(2025)·1 citation
08
[Submitted on 14 Jun 2024] (cross-list from hep-ph)
Bridging Electromagnetic and Gravitational Form Factors: Insights from LFHQCD
Xiaobin Wang🇨🇳 · Zanbin Xing🇨🇳 · Minghui Ding🇩🇪 · Khépani Raya🇪🇸 · Lei Chang🇨🇳
We propose an efficacious approach to derive the generalized parton distributions for the pion and proton, based upon prior knowledge of their respective parton distribution functions (PDFs). Our method leverages on integral representations of the electromagnetic form factors derived from the light-front holographic QCD (LFHQCD) formalism, coupled with PDFs computed from continuum Schwinger functional methods at the hadronic scale. Using these techniques, we calculate gravitational form factors and associated mass distributions for each hadron. Remarkably, our calculations yield results that closely match recent lattice QCD simulations conducted near the physical pion mass. This work not only deepens our understanding of hadronic structure but also highlights the efficacy of the LFHQCD approach in modeling fundamental properties of hadrons.
Comments:
6 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2406.09644 [pdf]
8 citations
09
[Submitted on 14 Jun 2024] (cross-list from hep-ph)
Steady state, displacement current and spin polarization for massless fermion in a shear flow
Shu Lin🇨🇳 · Ziyue Wang🇨🇳
We consider spin polarization of massless fermions in a shear flow, whose complete contributions contain magnetization current and side-jump current known from collisional chiral kinetic theory. We argue that the side-jump current adopts interpretation of displacement current. We explicitly determine the displacement current contribution in the steady state reached in shear flow for a QED plasma. We find the displacement contribution enhances the magnetization contribution at small and large momenta, but leads to a suppression effect at intermediate momenta. Major differences from previous studies on collisional effect are: (i) the fermions are in the same steady state as the medium rather than being probes; (ii) Compton scattering and pair annihilation are also included in addition to the Coulomb scattering considered before.
Comments:
20 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2406.10003 [pdf]
PRD(2025)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE