Nuclear Theory·nucl-th

Wednesday·February 15, 2023

6 papers—5 primary·1 cross-listed

01
[Submitted on 14 Feb 2023]
Time-dependent Hartree-Fock study of quasifission trajectories in reactions forming $^{294}$ Og
Patrick McGlynn · Cedric Simenel
Background: Fission modes in superheavy nuclei are expected to be impacted by quantum shell effects. Similar shell effects may be present in quasifission reactions, acting to hinder the mass equilibration process in heavy-ion collisions. Purpose: To investigate quasifission mechanisms in five different reactions forming $^{294}$ Og as a compound nucleus and compare quasifission trajectories with predicted fission modes. Methods: The potential energy surface (PES) of $^{294}$ Og is calculated using the static Hartree-Fock approach with BCS pairing correlations. Quasifission trajectories for central collisions at various energies are studied with the time-dependent Hartree-Fock theory. Results: The exit channel strongly depends on initial mass asymmetry and orientation, but it only exhibits small dependences in the reaction energy. The $^{48}$ Ca $+^{246}$ Cf reaction is affected by the PES topology, leading to either fusion or asymmetric fission. Spherical shell effects associated with the $Z = 50$ magic gap hinder charge and mass equilibrations in $^{126}$ Sn $+^{168}$ Er, resulting in large total kinetic energies and compact scission configurations. Conclusions: Quasifission trajectories can be interpreted in terms of the underlying PES for low excitation energies. Future investigations of quasifission with temperature and angular momentum dependent PES could be considered.
Comments:
14 pages, 11 figures, 6 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2302.06938 [pdf]
PRC(2023)·20 citations
02
[Submitted on 14 Feb 2023]
The $^{19}$ N( $n$ , $γ)^{20}$ N capture rate in light of the probable bubble nature of $^{20}$ N
V. Choudhary · M. Dan · R. Chatterjee · M. Kimura · W. Horiuchi · Shubhchintak · G. Singh
We aim to explore the bubble nature of the exotic nucleus $^{20}$ N within the microscopic antisymmetrized molecular dynamics (AMD) approach. Constraining its structural parameters, we analyse its static properties. Subsequently, we use the AMD infused finite-range distorted-wave Born approximation theory to calculate the Coulomb breakup of $^{20}$ N as an indirect approach to estimate the $^{19}$ N $(n, γ)^{20}$ N radiative capture rate.
Comments:
8 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2302.06986 [pdf]
EPJA(2024)·5 citations
03
[Submitted on 14 Feb 2023]
$E (5)$ -like emerging $γ$ -softness in $^{82}$ Kr
Chunxiao Zhou · Tao Wang
Recently the interacting bosom model with $S U (3)$ higher-order interactions was proposed by one of the authors, wherein unexpected $γ$ -softness can be emerged in this new model. This stimulates further discussion on the connections of the new $γ$ -softness and the realistic $γ$ -soft nuclei. In this paper, $E (5)$ -like $γ$ -softness arises when the $S U (3)$ fourth-order interaction $C^_{2}^{2} [S U (3)]$ is considered. And the corresponding transitional behaviors are similar to that from the $U (5)$ limit to the $O (6)$ limit in previous IBM-1, which provides a novel perspective for understanding the new model. Low-lying spectra, $B (E 2)$ values between the low-lying states and quadrupole moment of the first $2_{1}^{+}$ state are investigated. Experimental data of the $E (5)$ -like nucleus $^{82}$ Kr are compared with the calculated theoretical results, where the calculated low-lying level energies and the associated $B (E 2)$ values fit very well with the experimental data.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2302.07032 [pdf]
PRC(2023)·15 citations
04
[Submitted on 14 Feb 2023]
Directed and elliptic flows of protons and deuterons in HADES Au+Au collisions at $s_{NN} = 2.4$ GeV
Huan Du🇨🇳 · Gao-Feng Wei🇨🇳 · Gao-Chan Yong🇨🇳
Within a transport model coupled with a microscopic coalescence model, the directed and elliptic flows of protons and deuterons as well as their scalling properties are studied in the centrality of 20-30% Au+Au collisions at $s_{NN} = 2.4$ GeV. It is found that the flows as well as their scaling properties simulated with the isospin- and momentum-dependent nuclear mean field with an incompressibility $K_{0} = 230$ MeV fit fairly the HADES data, while those simulated with the commonly used momentum-independent nuclear mean field with an incompressibility $K_{0} = 380$ MeV can only fit partially the HADES data. Moreover, by checking the rapidity distributions of both protons and deuterons in the centrality of 0-10% Au+Au collisions at $s_{NN} = 2.4$ GeV, we find that the rapidity distributions of deuterons are underestimated while those of protons are overestimated by the simulations with the momentum-independent nuclear mean field. In contrast, the rapidity distributions of both protons and deuterons simulated with the isospin- and momentum-dependent nuclear mean field are in good agreement with the HADES data. Our findings imply that the momentum dependence of nuclear mean field is an unavoidable feature for a fundamental understanding of nuclear matter properties and for the successful interpretation of the HADES data.
Comments:
7 pages, 5 figures. Accepted for publication in Physics Letters B
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2302.07037 [pdf]
PLB(2023)·13 citations
05
[Submitted on 14 Feb 2023]
$^{113}$ Cd $β$ -decay spectrum and $g_{A}$ quenching using spectral moments
Joel Kostensalo · Eligio Lisi · Antonio Marrone · Jouni Suhonen
We present an alternative analysis of the $^{113}$ Cd $β$ -decay electron energy spectrum in terms of spectral moments $μ_{n}$ , corresponding to the averaged values of $n^{th}$ powers of the $β$ particle energy. The zeroth moment $μ_{0}$ is related to the decay rate, while higher moments $μ_{n}$ are related to the spectrum shape. The here advocated spectral-moment method (SMM) allows for a complementary understanding of previous results, obtained using the so-called spectrum-shape method (SSM) and its revised version, in terms of two free parameters: $r = g_{A} / g_{V}$ (the ratio of axial-vector to vector couplings) and $s$ (the small vector-like relativistic nuclear matrix element, $s$ -NME). We present numerical results for three different nuclear models with the conserved vector current hypothesis (CVC) assumption of $g_{V} = 1$ . We show that most of the spectral information can be captured by the first few moments which are simple quadratic forms (conic sections) in the $(r, s)$ plane: an ellipse for $n = 0$ and hyperbolae for $n \geq 1$ , all being nearly degenerate as a result of cancellations among nuclear matrix elements. The intersections of these curves, as obtained by equating theoretical and experimental values of $μ_{n}$ , identify the favored values of $(r, s)$ at a glance, without performing detailed fits. In particular, we find that values around $r \sim 1$ and $s \sim 1.6$ are consistently favored in each nuclear model, confirming the evidence for $g_{A}$ quenching in $^{113}$ Cd, and shedding light on the role of the $s$ -NME. We briefly discuss future applications of the SMM to other forbidden $β$ -decay spectra sensitive to $g_{A}$ .
Comments:
Revised version, results unchanged. Matches version published in PRC (title slightly shortened, text revised, appendices added, figures presented in different order)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2302.07048 [pdf]
PRC(2023)·18 citations
06
[Submitted on 13 Feb 2023] (cross-list from quant-ph)
A quantum-classical co-processing protocol towards simulating nuclear reactions on contemporary quantum hardware
Francesco Turro · Trevor Chistolini · Akel Hashim · Yosep Kim · William Livingston · Kyle. A. Wendt · Jonathan L Dubois · Francesco Pederiva · Sofia Quaglioni · David I. Santiago · Irfan Siddiqi
Quantum computers hold great promise for arriving at exact simulations of nuclear dynamical processes (e.g., scattering and reactions) that are paramount to the study of nuclear matter at the limit of stability and to explaining the formation of chemical elements in stars. However, quantum simulations of the unitary (real) time dynamics of fermionic many-body systems require a currently prohibitive number of reliable and long-lived qubits. We propose a co-processing algorithm for the simulation of real-time dynamics in which the time evolution of the spatial coordinates is carried out on a classical processor, while the evolution of the spin degrees of freedom is carried out on a quantum processor. This hybrid algorithm is demonstrated by a quantum simulation of the scattering of two neutrons performed at the Lawrence Berkeley National Laboratory's Advanced Quantum Testbed. We show that, after implementation of error mitigation strategies to improve the accuracy of the algorithm in addition to the use of either circuit compression techniques or tomography as methods to elucidate the onset of decoherence, this initial demonstration validates the principle of the proposed co-processing scheme. We anticipate that a generalization of this present scheme will open the way for (real-time) path integral simulations of nuclear scattering.
Comments:
12 pages, 10 figures
Subjects:
Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
arXiv:
2302.06734 [pdf]
PRA(2023)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE

Time-dependent Hartree-Fock study of quasifission trajectories in reactions forming 294Og

The 19N(n,γ)20N capture rate in light of the probable bubble nature of 20N

E(5)-like emerging γ-softness in 82Kr

Directed and elliptic flows of protons and deuterons in HADES Au+Au collisions at sNN​​=2.4 GeV

113Cd β-decay spectrum and gA​ quenching using spectral moments

A quantum-classical co-processing protocol towards simulating nuclear reactions on contemporary quantum hardware

Affiliations

Time-dependent Hartree-Fock study of quasifission trajectories in reactions forming $^{294}$ Og

The $^{19}$ N( $n$ , $γ)^{20}$ N capture rate in light of the probable bubble nature of $^{20}$ N

$E (5)$ -like emerging $γ$ -softness in $^{82}$ Kr

Directed and elliptic flows of protons and deuterons in HADES Au+Au collisions at $s_{NN} = 2.4$ GeV

$^{113}$ Cd $β$ -decay spectrum and $g_{A}$ quenching using spectral moments