Nuclear Theory·nucl-th

Wednesday·April 5, 2023

13 papers—8 primary·5 cross-listed

01
[Submitted on 3 Apr 2023]
Magnetic moments of $A = 3$ nuclei with chiral effective field theory operators
Soham Pal (1) · Shiplu Sarker (1) · Patrick J. Fasano (2) · Pieter Maris (1) · James P. Vary (1) · Mark A. Caprio (2) · Robert A. M. Basili (1) ((1) Iowa State University · (2) University of Notre-Dame)
Chiral effective field theory ( $χ$ EFT) provides a framework for obtaining internucleon interactions in a systematically improvable fashion from first principles, while also providing for the derivation of consistent electroweak current operators. In this work, we apply consistently derived interactions and currents towards calculating the magnetic dipole moments of the $A = 3$ systems Triton and Helium-3. We focus here on LENPIC interactions obtained using semilocal coordinate-space (SCS) regularization. Starting from the momentum-space representation of the LENPIC $χ$ EFT vector current, we derive the SCS-regularized magnetic dipole operator up through N2LO. We then carry out no-core shell model calculations for Triton and Helium-3 systems, using the SCS LENPIC interaction at N2LO in $χ$ EFT, and evaluate the magnetic dipole moments obtained using the consistently derived one-nucleon and two-nucleon electromagnetic currents. As anticipated by prior results with $χ$ EFT currents, the current corrections through N2LO provide improved, but not yet complete, agreement with experiment for the Triton and Helium-3 magnetic dipole moments.
Comments:
16 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2304.01389 [pdf]
PRC(2023)·10 citations
02
[Submitted on 4 Apr 2023]
Nuclear mass table in density functional approach inspired by neutron-star observations
Hana Gil · Nobuo Hinohara · Chang Ho Hyun · Kenichi Yoshida
Background: Nuclear energy-density functional (EDF) approach has been widely used to describe nuclear-matter equations of state (EoS) and properties of finite nuclei. Recent advancements in neutron-star (NS) observations have put constraints on the nuclear EoS. The Korea-IBS-Daegu-SKKU (KIDS) functional has been then developed to satisfy the NS observations and applied to homogeneous nuclear matter and spherical nuclei. Purpose: We examine the performance of the KIDS functional by calculating the masses and charge radii of even-even nuclei towards the drip lines. Method: The Kohn-Sham-Bogoliubov equation is solved by taking into account the axial deformation. Results: The root-mean-square deviation of the binding energy and the charge radius for the KIDS functional is 4.5--5.1 MeV and 0.03--0.04 fm, which is comparable to that for existing EDFs. The emergence and development of nuclear deformation in open-shell nuclei are well described. The location of the neutron drip line is according to the nuclear-matter parameter characterizing the low-mass NS. Conclusions: The NS-observation-inspired EDF offers a reasonable reproduction of the structures of finite nuclei. A future global optimization including more nuclear data will give better accuracy and high predictive power of neutron-rich nuclei.
Comments:
9 pages, 6 figures, and 2 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2304.01546 [pdf]
PRC(2023)·3 citations
03
[Submitted on 4 Apr 2023]
Linear Stability of Shock Waves in Ultrarelativistic Anisotropic Hydrodynamics
Aleksandr Kovalenko🇷🇺
Linear stability of a plane shock waves in ultrarelativistic anisotropic hydrodynamics is investigated. The properties of the amplitudes of perturbations of physical quantities are studied depending on the components of the wave vector of a small harmonic perturbation. Analytical calculationsfor the longitudinal and transverse propagation of shock wave normal with respect to the anisotropy axis (beam-axis) and numerical calculations for an arbitrary polar angle are carried out.
Comments:
26 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2304.01653 [pdf]
EPJC(2023)·1 citation
04
[Submitted on 4 Apr 2023]
Investigation of the cause of the discrepancies between calculated running sums for nuclear matrix elements of two-neutrino double- $β$ decay
J. Terasaki🇨🇿
A qualitative difference in the running sum for the nuclear matrix element of the two-neutrino double- $β$ decay of $^{136}$ Xe was found four years ago between quasiparticle random-phase approximation (QRPA) and shell model calculations. The former result has large increase and decrease with respect to the excitation energy of the intermediate state, and the latter one is an almost monotonically and mildly increasing function. My QRPA calculations independently of the above one do not have a remarkable decrease. This discrepancy is a serious problem affecting the reliability of calculations of the neutrinoless double- $β$ decay, and the cause was unknown. I perform several relevant test calculations and make an analytical consideration to find the cause, which is found to be in the strength of the attractive interactions. The possible major local decrease in the running sum is also explained analytically. The interactions of my QRPA calculation are appropriate in terms of the strength, thus the almost monotonic behavior is reasonable.
Comments:
13 pages, 7 figures, 1 table
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2304.01719 [pdf]
PRC(2023)·2 citations
05
[Submitted on 4 Apr 2023]
Relativistic Hartree-Fock Chiral Lagrangians with confinement, nucleon finite size and short-range effects
M. Chamseddine🇫🇷 · J. Margueron🇫🇷 · G. Chanfray🇫🇷 · H. Hansen🇫🇷 · R. Somasundaram🇺🇸
A relativistic Hartree-Fock Lagrangian including a chiral potential and nucleon polarisation is investigated in hopes of providing a better description of dense nuclear matter. We fully consider the contribution of the exchange Fock term to the energy and the self-energies, and in addition we investigate the nucleon's compositeness and finite size effects (confinement and form factors) and short range correlations modeled by a Jastrow ansatz. These effects are added step by step, such that their impact on the dense matter properties can be analysed in details. The parameters of the model are adjusted to reproduce fundamental properties related to the QCD theory at low energy, such as the chiral symmetry breaking, nucleon's quark substructure and Lattice-QCD predictions, as well as two empirical properties at saturation: the binding energy and the density. All other empirical parameters, e.g., symmetry energy and its slope, incompressibility modulus, effective mass, as well as spin-isospin Landau-Midgal parameter are predictions of the models and can be used to evaluate the gain of the different approximation schemes in describing nuclear properties. Bayesian statistics is employed in order to propagate parameter uncertainties into predictions for the nuclear matter properties. We show that the splitting of the effective Landau mass is largely influenced by the value of the $ρ^{T}$ coupling, and we show that the fit to the symmetry energy, which induces an increase of the coupling constant $g_{ρ}$ by about 20-25% compared to the case where it is fixed by the quark model, provides a very good EoS compatible with the present nuclear physics knowledge.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2304.01817 [pdf]
EPJA(2023)·11 citations
06
[Submitted on 4 Apr 2023]
Nucleosynthesis and observation of the heaviest elements
E. M. Holmbeck · T. M. Sprouse · M. R. Mumpower
The rapid neutron capture or 'r process' of nucleosynthesis is believed to be responsible for the production of approximately half the natural abundance of heavy elements found on the periodic table above iron (with proton number $Z = 26$ ) and all of the heavy elements above bismuth ( $Z = 83$ ). In the course of creating the actinides and potentially superheavies, the r process must necessarily synthesize superheavy nuclei (those with extreme proton numbers, neutron numbers or both) far from isotopes accessible in the laboratory. Many questions about this process remain unanswered, such as 'where in nature may this process occur?' and 'what are the heaviest species created by this process?' In this review, we survey at a high level the nuclear properties relevant for the heaviest elements thought to be created in the r process. We provide a synopsis of the production and destruction mechanisms of these heavy species, in particular the actinides and superheavies, and discuss these heavy elements in relation to the astrophysical r process. We review the observational evidence of actinides found in the Solar system and in metal-poor stars and comment on the prospective of observing heavy-element production in explosive astrophysical events. Finally, we discuss the possibility that future observations and laboratory experiments will provide new information in understanding the production of the heaviest elements.
Comments:
63 pages, 17 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2304.01850 [pdf]
EPJA(2023)·31 citations
07
[Submitted on 4 Apr 2023]
Hybrid stars with reactive interfaces: analysis within the Nambu-Jona-Lasinio model
C. H. Lenzi🇧🇷 · G. Lugones🇧🇷 · C. Vasquez🇧🇷
It has been shown recently that quark-hadron conversions at the interface of a hybrid star may have a key role on the dynamic stability of the compact object. In this work we perform a systematic study of hybrid stars with reactive interfaces using a model-agnostic piecewise-polytropic hadronic equation of state and the Nambu-Jona-Lasinio model for three-flavor quark matter. For the hadronic phase we use a soft, an intermediate and a stiff parametrization that match at $1.1 n_{0}$ {with predictions} based on chiral effective field theory (cEFT) interactions. In the NJL Lagrangian we include scalar, vector and 't Hooft interactions. The vector coupling constant $g_{v}$ is treated as a free parameter. We also consider that there is a split between the deconfinement and the chiral phase transitions which is controlled by changing the conventional value of the vacuum pressure $- Ω_{0}$ in the NJL thermodynamic potential by $- (Ω_{0} + δ Ω_{0})$ , being $δ Ω_{0}$ a free parameter. We analyze the mass-radius ( $M$ - $R$ ) relation in the case of rapid ( $τ ≪ 1 ms$ ) and slow ( $τ ≫ 1 ms$ ) conversions, being $τ$ the reaction timescale. In the case of slow interface reactions we find $M$ - $R$ curves with a cusp at the maximum mass point where a pure hadronic branch and a slow-stable hybrid star (SSHS) branch coincide. We find that the length of the slow-stable branch grows with the increase of the transition density and the energy density jump at the hadron-quark interface. We calculate the tidal deformabilities of SSHSs and analyse them in the light of the GW170817 event.
Comments:
12 pages, 4 figures, to be published in Physical Review D
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2304.01898 [pdf]
PRD(2023)·11 citations
08
[Submitted on 4 Apr 2023]
Inference of the low-energy constants in $Δ$ -full chiral effective field theory including a correlated truncation error
Isak Svensson · Andreas Ekström · Christian Forssén
We sample the posterior probability distributions of the low-energy constants (LECs) in $Δ$ -full chiral effective field theory ( $χ$ EFT) up to third order. We use eigenvector continuation for fast and accurate emulation of the likelihood and Hamiltonian Monte Carlo to draw effectively independent samples from the posteriors. Our Bayesian inference is conditioned on the Granada database of neutron-proton ( $n p$ ) cross sections and polarizations. We use priors grounded in $χ$ EFT assumptions and a Roy-Steiner analysis of pion-nucleon scattering data. We model correlated EFT truncation errors using a two-feature Gaussian process, and find correlation lengths for $n p$ scattering energies and angles in the ranges 45--83 MeV and 24--39 degrees, respectively. These correlations yield a non-diagonal covariance matrix and reduce the number of independent scattering data with a factor of 8 and 4 at the second and third chiral orders, respectively. The relatively small difference between the second and third order predictions in $Δ$ -full $χ$ EFT suppresses the marginal variance of the truncation error and the effects of its correlation structure. Our results are particularly important for analyzing the predictive capabilities in \textit{ab initio} nuclear theory.
Comments:
17 pages, 12 figures. Updated to match Phys. Rev. C version as closely as possible
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2304.02004 [pdf]
PRC(2024)·23 citations
09
[Submitted on 3 Apr 2023] (cross-list from hep-th)
Novel transition dynamics of topological solitons
Kentaro Nishimura🇯🇵 · Noriyuki Sogabe🇺🇸
Continuous phase transitions can be classified into ones characterized by local-order parameters and others that need additional topological constraints. The critical dynamics near the former transitions have been extensively studied, but the latter is less understood. We fill this gap in knowledge by studying the transition dynamics to a parity-breaking topological ground state called the chiral soliton lattice in quantum chromodynamics at finite temperature, baryon chemical potential, and external magnetic field. We find a slowing down of the soliton's translational motion as the critical magnetic field approaches while the local dissipation rate remains finite. Therefore, the characteristic time it takes to converge to the stationary state associated with a finite topological number strongly depends on the initial configuration: whether it forms a solitonic structure or not.
Comments:
8 pages, 4 figures; published version
Subjects:
High Energy Physics — Theory (hep-th); cond-mat.mtrl-sci (cond-mat.mtrl-sci); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2304.01264 [pdf]
PRD(2024)·2 citations
10
[Submitted on 4 Apr 2023] (cross-list from astro-ph.HE)
The proto-neutron star inner crust in the liquid phase
H. Dinh Thi🇫🇷 · A. F. Fantina🇫🇷 · F. Gulminelli🇫🇷
The crust of a neutron star is known to melt at a temperature that increases with increasing matter density, up to about $1 0^{10}$ K. At such high temperatures and beyond, the crustal ions are put into collective motion and the associated entropy contribution can affect both the thermodynamic properties and the composition of matter. We studied the importance of this effect in different thermodynamic conditions relevant to the inner crust of the proto-neutron star, both at beta equilibrium and in the fixed-proton-fraction regime. To this aim, we solved the hydrodynamic equations for an ion moving in an incompressible, irrotational, and non-viscous fluid, with different boundary conditions, thus leading to different prescriptions for the ion effective mass. We then employed a compressible liquid-drop approach in the one-component plasma approximation, including the renormalisation of the ion mass to account for the influence of the surrounding medium. We show that the cluster size is determined by the competition between the ion centre-of-mass motion and the interface properties, namely the Coulomb, surface, and curvature energies. In particular, including the translational free energy in the minimisation procedure can significantly reduce the optimal number of nucleons in the clusters and lead to an early dissolution of clusters in dense beta-equilibrated matter. On the other hand, we find that the impact of translational motion is reduced in scenarios where the proton fraction is assumed constant and is almost negligible on the inner-crust equation of state. Our results show that the translational degrees of freedom affect the equilibrium composition of beta-equilibrated matter and the density and pressure of the crust-core transition in a non-negligible way, highlighting the importance of its inclusion when modelling the finite-temperature inner crust of the (proto-)neutron star.
Comments:
14 pages, 13 figures, accepted for publication in Astronomy and Astrophysics
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2304.01584 [pdf]
Astron.Astrophys.(2023)·17 citations
11
[Submitted on 4 Apr 2023] (cross-list from hep-ph)
Anomalies in Particle Physics
Andreas Crivellin🇨🇭
I provide a (personal) review of the current hints for physics beyond the Standard Model, called ``anomalies'', obtained both at the intensity frontier (flavour and electroweak precision observables) and in direct LHC searches. This includes the deviations from the Standard Model predictions in semi-leptonic $B$ decays, the anomalous magnetic moment of the muon, the Cabibbo Angle Anomaly, the $W$ mass as well as non-resonant di-lepton searches, the hints for new scalar particles around $\approx 95$ GeV, $\approx 151$ GeV, $\approx 670$ GeV and the (di-)di-jet excess at $\approx 1$ TeV ( $\approx 3.6$ TeV). Possible explanations in terms of new particles are briefly summarized and discussed.
Comments:
17 pages, 10 figures, proceedings for: 8 $^{th}$ Symposium on Prospects in the Physics of Discrete Symmetries (DISCRETE 2022), 7-11 November 2022 Baden-Baden, Germany
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2304.01694 [pdf]
PoS(2024)·8 citations
12
[Submitted on 4 Apr 2023] (cross-list from hep-ph)
$γ Z$ -Exchange Contributions in Low-Energy Parity-Violating $e p$ Scattering
Qian-Qian Guo🇨🇳 · Hai-Qing Zhou🇨🇳
In this work, the $γ Z$ -exchange contributions in the low-energy elastic parity-violating $e p$ scattering are discussed with the approximation $m_{e} = 0$ . By expanding the $γ pp$ and $Z pp$ interactions on the momentum of photon and considering both the leading-order and the next-to-leading order interactions, we calculate the amplitudes of the $γ Z$ -exchange diagrams. After performing the loop integral, we expand the results in the low energy limit, and obtain the analytic expressions for the amplitudes. Numerical comparisons show that the analytic expressions are very close to the full results over a large region. We investigate the power behaviors of these contributions and find that some are enhanced by a kinematic factor in the low energy limit. Additionally, in some cases, the imaginary parts of the contributions from the next-to-leading-order interactions are at the same order as those from the leading-order interactions. Furthermore, the corresponding contributions to the physical observable quantity $A_{PV}$ are also discussed. Combining all the properties together, we conclude that these analytic expressions describe the leading-order contributions of all $γ Z$ -exchange helicity amplitudes in the region with $α_{e} ≪ Q / M_{N} \sim δ / M_{N}^{2} ≪ 1$ , where $α_{e}$ is the fine structure constant, $M_{N}$ is the mass of proton, $Q$ and $δ$ are the small quantities related to the momentum transfer and the center-of-mass energy.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2304.01813 [pdf]
PRC(2023)·3 citations
13
[Submitted on 20 Feb 2023] (cross-list from hep-ex)
New model comparison for semi-inclusive charged-current electron and muon neutrino scattering by $^{40}$ Ar in the energy range of the MicroBooNE experiment
J. M. Franco-Patino🇪🇸 · S. Dolan🇨🇭 · R. González-Jiménez🇪🇸 · M.B. Barbaro🇮🇹 · J.A. Caballero🇪🇸 · G.D. Megias🇪🇸
In this work we present a comparison of semi-inclusive muon and electron neutrino cross sections with $^{40}$ Ar target measured by the MicroBooNE Collaboration with the predictions of an unfactorized model based on the relativistic distorted wave impulse approximation (RDWIA) and the SuSAv2-MEC model implemented in the neutrino event generator GENIE. The predictions based on the RDWIA approach, with a realistic description of the initial state and a phenomenological relativistic complex optical potential for the description of final state interactions, better describe the measured cross sections than GENIE-SuSAv2 and RDWIA with a purely real potential.
Subjects:
High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2304.01916 [pdf]
PRD(2024)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE