Nuclear Theory·nucl-th

Thursday·December 14, 2023

13 papers—8 primary·5 cross-listed

01
[Submitted on 11 Dec 2023]
Quantum Computing for Nuclear Physics
Martin J. Savage🇺🇸
Future quantum computers are anticipated to be able to perform simulations of quantum many-body systems and quantum field theories that lie beyond the capabilities of classical computation. This will lead to new insights and predictions for systems ranging from dense non-equilibrium matter, to low-energy nuclear structure and reactions, to high-energy collisions. I present an overview of digital quantum simulations in nuclear physics, with select examples relevant for studies of quark matter.
Comments:
Conference proceedings for Quark Matter 2023, Sept 2023, Houston, Texas, USA. 6 pages and 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex)
arXiv:
2312.07617 [pdf]
EPJ Web Conf.(2024)·17 citations
02
[Submitted on 12 Dec 2023]
Theoretical developments on the initial state in relativistic particle collisions
Heikki Mäntysaari🇫🇮
We discuss recent progress towards developing accurate initial state descriptions for heavy ion collisions focusing on weak coupling based approaches, that enable one to constrain the high-energy structure of nuclei from deep inelastic scattering or proton-nucleus collisions. We review recent developments to determine the event-by-event fluctuating nuclear geometry, to describe gluon saturation phenomena at next-to-leading order accuracy, and to include longitudinal dynamics to the initial state descriptions.
Comments:
6 pages, 5 figures. Presented at the XXXth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2023), Houston, Texas, USA
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.07805 [pdf]
EPJ Web Conf.(2024)·2 citations
03
[Submitted on 13 Dec 2023]
{\alpha}-decay half-lives for even-even isotopes of W to U
Yong-Beom Choi · Chang-Hwan Lee · Myeong-Hwan Mun · Soonchul Choi · Youngman Kim
We investigate {\alpha}-decay half-lives for 74 {\le} Z {\le} 92 even-even nuclei within the semiclassical WKB approximation in deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). The {\alpha}-particle preformation factors are estimated from cluster-formation model using both empirical AME2020 binding energies and numerical ones obtained by a deep neural network (DNN) study in which available DRHBc binding energies are used as training set. We find that our estimated {\alpha}-decay half-lives are qualitatively in agree with experimental results. We also compare our results with the empirical formulae, ZZCW and UNIV. Based on these observation, we extend our predictions of {\alpha}-decay half-lives for the isotopes whose experimental data are not available.
Comments:
19 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.07872 [pdf]
PRC(2024)·12 citations
04
[Submitted on 13 Dec 2023]
Shell-Model Description of the Isospin-Symmetry-Breaking Correction to Gamow-Teller $β$ -Decay Rates and Their Mirror Asymmetries
Latsamy Xayavong · Yeunhwan Lim
The isospin-symmetry breaking correction, denoted as $δ_{C}$ , is introduced for the first time within the shell-model framework to the nuclear matrix element of Gamow-Teller transitions. $δ_{C}$ is separated into two components: the isospin mixing term, $δ_{C 1}$ , induced by the Coulomb and nuclear charge-dependent forces in the effective Hamiltonian, and the radial mismatch term, $δ_{C 2}$ , arising from differences between proton and neutron realistic wave functions. Consequently, the refinement strategy developed for superallowed $0^{+} \to 0^{+}$ Fermi transitions is applied to Gamow-Teller transitions as well. It is demonstrated that, to a given precision level, the shell model calculation of $δ_{C}$ converges much faster than the calculation of the transition matrix element. Furthermore, higher-order correction terms are investigated and considered for consistent study of our works. Various interesting properties of the leading correction terms are discovered within the two-level model and parentage expansion of the one-body transition densities in angular momentum and isospin spaces. One such property is the dependence of $δ_{C 1}$ on the isospin admixture amplitude, $α$ , starting from the first order, while the same model yields $δ_{C 1} = α^{2}$ for Fermi transitions. The calculated $δ_{C}$ values are then utilized to evaluate the mirror asymmetry of Gamow-Teller transition strengths, which are compared with available experimental data and other theoretical calculations. Due to the refined fitting procedure of the Woods-Saxon potential parameters and the improved convergence as a function of intermediate state number, our results show better agreement on average compared to those of Smirnova and Volpe [Nucl. Phys. {\bf A 714}, 441 (2003)].
Comments:
21 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.07900 [pdf]
PRC(2025)·7 citations
05
[Submitted on 13 Dec 2023]
Neutrinos from pre-supernova in the framework of TQRPA method
A. A. Dzhioev · A. V. Yudin · N. V. Dunina-Barkovskaya · A. I. Vdovin
We propose a new method for calculating spectra and luminosities for (anti)neutrinos produced in the pre-supernova environment by weak processes with hot nuclei. It is based on the thermal quasiparticle random phase approximation (TQRPA), that allows microscopic thermodynamically consistent calculations of the weak-interaction response of nuclei at finite temperatures. For realistic representative pre-supernova conditions from the stellar evolution code MESA, we compute (anti)neutrino luminosities and spectra arising from neutral- and charged-current weak reactions with hot $^{56}$ Fe and compare them with the contribution of thermal processes. We find that the TQRPA approach produces not only a higher total luminosity of electron neutrinos (mainly born in the electron capture reaction), compared to the standard technique based on the large-scale shell model (LSSM) weak-interaction rates, but also a harder neutrino spectrum. Besides, applying the TQRPA and LSSM, we find that in the context of electron antineutrino generation, the neutral-current nuclear de-excitation (ND) process via neutrino-antineutrino pair emission is at least as important as the electron-positron pair annihilation process. We also show that flavor oscillations enhance the high-energy contribution of the ND process to the electron antineutrino flux. This could potentially be important for pre-supernova antineutrino registration by the Earth's detectors.
Comments:
12 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2312.07988 [pdf]
MNRAS(2023)·7 citations
06
[Submitted on 13 Dec 2023]
Non-hydrodynamic response in QCD-like plasma
Weiyao Ke🇨🇳 · Yi Yin🇨🇳
Quark-gluon plasma's (QGP) properties at non-hydrodynamic and non-perturbative regimes remain largely unexplored. Here, we examine the response functions describing how a QGP-like plasma responds to initial energy-momentum disturbance in both static and Bjorken-expanding plasma at non-hydrodynamic gradient using the Boltzmann equation in the relaxation-time approximation (RTA). We show that the resulting response functions are remarkably similar in both static and expanding backgrounds at non-hydrodynamic gradients. While non-hydrodynamic response can not be described by the conventional first-order and second-order theories, its behavior is reasonably captured by the extended version of hydrodynamics proposed by us (arXiv: 2208.01046). The potential sensitivity of the Euclidean correlator to non-hydrodynamic response is also illustrated.
Comments:
32 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2312.08062 [pdf]
JHEP(2024)·4 citations
07
[Submitted on 13 Dec 2023]
How to explain ENDF-6 to computers: A formal ENDF format description language
Georg Schnabel · Daniel Lopez Aldama · Roberto Capote
The ENDF-6 format, widely used worldwide for storing and disseminating nuclear data, is managed by the Cross Sections Evaluation Working Group (CSEWG) and fully documented in the ENDF-6 formats manual. This manual employs a combination of formal and natural language, introducing the possibility of ambiguity in certain parts of the format specification. To eliminate the possibility of ambiguity, this contribution proposes a generalization of the formal language used in the ENDF-6 formats manual, which is precisely defined in extended Backus-Naur form (EBNF). This formalization also offers several other advantages, notably reducing the complexity of creating and updating parsing and validation programs for ENDF-6 formatted files. Moreover, the availability of a formal description enables the automatic mapping of the low-level ENDF-6 representation, provided by a sequence of numbers, to a more human-friendly hierarchical representation with variable names. Demonstrating these advantages, almost the entire ENDF-6 format description has been translated into the proposed formal language, accompanied by a reference implementation of a parser/translator. This implementation leverages the formal format specification to enable reading, writing, and validating ENDF-6 formatted files.
Comments:
31 pages
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.08249 [pdf]
0 citations
08
[Submitted on 13 Dec 2023]
$^{12}$ C and $α$ -clusters, $0^{+}$ spectrum, and Hoyle-state candidates in $^{24}$ Mg
J. Cseh · G. Riczu · D. G. Jenkins
Background: A recent inelastic alpha-scattering experiment [Phys. Rev. Lett. 129, 102701 (2022)] found $0^{+}$ resonances in $^{24}$ Mg on and above the $^{12}$ C+ $^{12}$ C break-up threshold. It has been conjectured that the states have a $^{12}$ C+ $^{12}$ C cluster structure, and play a similar role in accelerating $^{12}$ C+ $^{12}$ C fusion to the manner in which the Hoyle state accelerates production of $^{12}$ C in massive stars. Purpose: We wish to build up a quantitative theoretical basis for the considerations of the Hoyle-state paradigm, by calculating the distribution of the $0^{+}$ states in the shell, as well as in the relevant cluster models. Methods: We determine the spectrum of excited $0^{+}$ states in $^{24}$ Mg nucleus using multiconfigurational dynamical symmetry calculations leading to a unified description of the quartet (or shell), $^{12}$ C+ $^{12}$ C and $^{20}$ Ne+ $^{4}$ He cluster configurations. Results: The density of $0^{+}$ states in the quartet spectrum is comparable to that found in experiment; however, the density of cluster states is considerably less. Conclusions: The recently observed alpha-scattering resonances do not seem to be simple $^{12}$ C+ $^{12}$ C cluster states, but are more plausibly interpreted as fragmented cluster states due to coupling to quartet excitations, as background states.
Comments:
7 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.08318 [pdf]
2 citations
09
[Submitted on 12 Dec 2023] (cross-list from hep-lat)
Continuum extrapolated high order baryon fluctuations
Szabolcs Borsányi🇩🇪 · Zoltán Fodor🇩🇪 · Jana N. Guenther🇩🇪 · Sándor D. Katz🇭🇺 · Paolo Parotto🇺🇸 · Attila Pásztor🇭🇺 · Dávid Pesznyák🇭🇺 · Kálmán K. Szabó🇩🇪 · Chik Him Wong🇩🇪
Fluctuations play a key role in the study of QCD phases. Lattice QCD is a valuable tool to calculate them, but going to high orders is challenging. Up to the fourth order, continuum results are available since 2015. We present the first continuum results for sixth order baryon fluctuations for temperatures between $T = 130 - 200$ MeV, and eighth order at $T = 145$ MeV in a fixed volume. We show that for $T \leq 145$ MeV, relevant for criticality search, finite volume effects are under control. Our results are in sharp contrast with well known results in the literature obtained at finite lattice spacing.
Comments:
5 pages, 2 figures (main text) + 5 pages, 7 figures (supplemental material)
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2312.07528 [pdf]
PRD(2024)·34 citations
10
[Submitted on 13 Dec 2023] (cross-list from hep-lat)
Leveraging neural control variates for enhanced precision in lattice field theory
Paulo F. Bedaque🇺🇸 · Hyunwoo Oh🇺🇸
Results obtained with stochastic methods have an inherent uncertainty due to the finite number of samples that can be achieved in practice. In lattice QCD this problem is particularly salient in some observables like, for instance, observables involving one or more baryons and it is the main problem preventing the calculation of nuclear forces from first principles. The method of control variables has been used extensively in statistics and it amounts to computing the expectation value of the difference between the observable of interest and another observable whose average is known to be zero but is correlated with the observable of interest. Recently, control variates methods emerged as a promising solution in the context of lattice field theories. In our current study, instead of relying on an educated guess to determine the control variate, we utilize a neural network to parametrize this function. Using 1+1 dimensional scalar field theory as a testbed, we demonstrate that this neural network approach yields substantial improvements. Notably, our findings indicate that the neural network ansatz is particularly effective in the strong coupling regime.
Comments:
6 pages, 3 figures
Subjects:
High Energy Physics — Lattice (hep-lat); Machine Learning (cs.LG); Nuclear Theory (nucl-th)
arXiv:
2312.08228 [pdf]
PRD(2024)·14 citations
11
[Submitted on 13 Dec 2023] (cross-list from cond-mat.quant-gas)
Complex-valued in-medium potential between heavy impurities in ultracold atoms
Yukinao Akamatsu · Shimpei Endo · Keisuke Fujii · Masaru Hongo
We formulate the induced potential in a finite temperature cold atomic medium between two heavy impurities, or polarons, which is shown to be \textit{complex-valued} in general. The imaginary part of the complex-valued potential describes a decoherence effect, and thus, the resulting Schrödinger equation for the two polarons acquires a non-Hermitian term. We apply the developed formulation to two representative cases of polarons interacting with medium particles through the $s$ -wave contact interaction: (i) the normal phase of single-component (i.e., spin-polarized) fermions using the fermionic field theory, and (ii) a superfluid phase using the superfluid effective field theory, which is valid either for a Bose-Einstein condensate (BEC) of a single-component Bose gas or for the BEC-BCS crossover in two-component fermions at a low-energy regime. Computing the leading-order term, the imaginary part of the potential in both cases is found to show a universal $r^{- 2}$ behavior at long distance. We propose three experimental ways to observe the effects of the universal imaginary potential in cold atoms.
Comments:
16 pages, version accepted for publication in Phys. Rev. A
Subjects:
Quantum Gases (cond-mat.quant-gas); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2312.08241 [pdf]
PRA(2024)·1 citation
12
[Submitted on 13 Dec 2023] (cross-list from hep-ph)
Spin relaxation rate for baryons in thermal pion gas
Yoshimasa Hidaka🇯🇵 · Masaru Hongo🇯🇵 · Mikhail Stephanov🇺🇸 · Ho-Ung Yee🇺🇸
We study the relaxation dynamics of the spin polarization of baryons (nucleon and $Λ$ -baryon), in a thermal pion gas as a simple model of the hadronic phase of the QCD plasma produced in relativistic heavy-ion collisions. For this purpose, we formulate the quantum kinetic theory for the spin density matrix of baryons in the leading order of the gradient expansion. Considering the baryon-pion elastic scattering processes as the dominant interaction between baryons and thermal pions, we compute the spin relaxation rate of nucleons and $Λ$ -baryons in a pion gas up to temperature 200 MeV. In the case of nucleons, we evaluate the spin relaxation rate in the $s$ -channel resonance approximation, based on the known experimental data on $Δ$ -resonances. We also estimate the spin relaxation rate for $Λ$ -baryons, based on experimental inputs and theoretical models for the low-energy $Λ$ $π$ scattering, including the chiral perturbation theory.
Comments:
16 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2312.08266 [pdf]
PRC(2024)·25 citations
13
[Submitted on 13 Dec 2023] (cross-list from hep-ph)
Nonrelativistic nuclear reduction for tensor couplings in dark matter direct detection and $μ \to e$ conversion
Ayala Glick-Magid🇺🇸
The nonrelativistic effective field theory (NRET) is widely used in dark matter direct detection and charged-lepton flavor violation studies through $μ \to e$ conversion. However, existing literature has not fully considered tensor couplings. This study fills this gap by utilizing an innovative tensor decomposition method, extending NRET to incorporate previously overlooked tensor interactions. This development is expected to have a significant impact on ongoing experiments seeking physics beyond the Standard Model and on our understanding of the new-physics interactions. Notably, we identify additional operators in $μ \to e$ conversion that are absent in scalar and vector couplings. To support further research and experimental analyses, comprehensive tables featuring tensor matrix elements and their corresponding operators are provided.
Comments:
9 pages, 3 tables, accepted version by PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2312.08339 [pdf]
PRD(2024)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE