Nuclear Theory·nucl-th

Thursday·December 16, 2021

13 papers—7 primary·6 cross-listed

01
[Submitted on 14 Dec 2021]
Dark matter component in hadronic models with short-range correlations
O. Lourenço🇧🇷 · T. Frederico🇧🇷 · M. Dutra🇧🇷
A relativistic mean field hadronic model with a dark matter (DM) particle coupled to nucleons including short-range correlations (SRC) is applied to study neutron stars (NS). The lightest neutralino is chosen as the dark particle candidate, which interacts with nucleons by the exchange of Higgs bosons. A detailed thermodynamical analysis shows that the contribution of the DM fermions to the energy density of the matter composed by these particles and nucleons is completely dominated by the DM kinetic terms. The model reproduces satisfactorily the constraints on the mass-radius diagram obtained from the analysis of the combined data from the NICER mission, LIGO and Virgo collaborations, and mass measurements from radio observations. We show that the SRC balance the reduction of the neutron star mass due to the DM component, and because of that the model is able to present more massive NS. We also present a study of the effect, in the NS mass-radius profiles, of the uncertainties in some bulk parameters related to the hadronic sector. We find that it is possible to generate parametrizations, with DM content, compatible with the recent astrophysical constraints and with the uncertainty in the symmetry energy slope obtained from the results reported by the updated Lead Radius EXperiment (PREX-2).
Comments:
12 pages, 12 figures. Published in Phys. Rev. D. Some smaller text revisions implemented
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2112.07716 [pdf]
PRD(2022)·35 citations
02
[Submitted on 15 Dec 2021]
4 $α$ linear-chain state produced by $^{9}$ Be+ $^{9}$ Be collision
Tomoyuki Baba · Yasutaka Taniguchi · Masaaki Kimura
Extreme nuclear deformations provide great insight into the geometric formation of quantum many-body systems. In this work, the $4 α + 2 n$ linear chain is assessed in $^{18}$ O. We predict excitation energies, moment-of-inertia, $α$ -, and $^{9}$ Be-decay widths by using the antisymmetrized molecular dynamics. We show that the $K^{π} = 3^{-}$ linear-chain states may be verified by the head-on $^{9} Be +^{9} Be$ collision experiments.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2112.07864 [pdf]
PRC(2022)·1 citation
03
[Submitted on 15 Dec 2021]
Neutrinoless double-beta decay: combining quantum Monte Carlo and the nuclear shell model with the generalized contact formalism
Ronen Weiss🇺🇸 · Pablo Soriano🇪🇸 · Alessandro Lovato🇺🇸 · Jaview Menendez🇪🇸 · R. B. Wiringa🇺🇸
We devise a framework based on the generalized contact formalism that combines the nuclear shell model and quantum Monte Carlo methods and compute the neutrinoless double-beta decay of experimentally relevant nuclei, including $^{76}$ Ge, $^{130}$ Te, and $^{136}$ Xe. In light nuclei, we validate our nuclear matrix element calculations by comparing against accurate variational Monte Carlo results. Due to additional correlations captured by quantum Monte Carlo and introduced within the generalized contact formalism, in heavier systems, we obtain long-range nuclear matrix elements that are about 30% smaller than previous shell-model results. We also evaluate the recently recognized short-range nuclear matrix element estimating its coupling by the charge-independence-breaking term of the Argonne $v_{18}$ potential used in the Monte Carlo calculations. Our results indicate an enhancement of the total nuclear matrix element by around 30%.
Comments:
14 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2112.08146 [pdf]
PRC(2022)·50 citations
04
[Submitted on 15 Dec 2021]
On the Photoproduction Reactions $γ d \to π N N$
William J. Briscoe (GWU)🇺🇸 · Alexander E. Kudryavtsev (ITEP)🇺🇸 · Igor I. Strakovsky (GWU)🇺🇸 · Vladimir E. Tarasov (ITEP)🇷🇺 · Ron L. Workman (GWU)🇺🇸
A review of our works providing a theoretical description of incoherent pion photoproduction on the deuteron is presented. The existing $γ d \to π N N$ data are analysed, especially those obtained more recently by the CLAS Collaboration at JLab, the A2 Collaboration at MAMI at Mainz, and the PION@MAX-lab Collaboration at Lund. A procedure, which accounts for the final state interactions (FSI), is applied to extract $γ n \to π N$ differential cross sections from the deuteron data. The role of FSI is discussed. We also comment on the results of other works in connection with some discrepancies seen in comparing the model with experiment. The electromagnetic properties of baryon $N^{*}$ resonances, improved using the extracted $γ n \to π N$ differential cross sections, are presented. A model description of the cross section data from charged-pion photoproduction reactions $γ d \to π^{\pm} N N$ near threshold is also given. The $γ d \to π^{-} pp$ data are used to extract the $E_{0 +}$ multipole and total crsoss sections of the reaction $γ n \to π^{-} p$ near threshold.
Comments:
35 pages, 10 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2112.08150 [pdf]
EPJA(2022)·14 citations
05
[Submitted on 15 Dec 2021]
Investigating Signatures of Phase Transitions in Neutron-Star Cores
Rahul Somasundaram🇫🇷 · Ingo Tews🇺🇸 · Jérôme Margueron🇫🇷
Neutron stars explore matter at the highest densities in the universe such that their inner cores might undergo a phase transition from hadronic to exotic phases, e.g., quark matter. Such a transition could be associated with non-trivial structures in the density behavior of the speed of sound such as jumps and sharp peaks. Here, we employ a physics-agnostic approach to model the density dependence of the speed of sound in neutron stars and study to what extent the existence of non-trivial structures can be inferred from existing astrophysical observations of neutron stars. For this, we exhaustively study different equations of state, including as well those with explicit first-order phase transitions. We obtain a large number of different EoSs which reproduce the same astrophysical observations and obey the same physical constraints such as mechanical stability and causality. Among them, some have non-trivial structures in the sound speed while others do not. We conclude that astrophysical information to date do not require the existence of a phase transition to quark matter in the density range explored in the core of neutron stars.
Comments:
8 pages, 5 figures. Comments welcome
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2112.08157 [pdf]
PRC(2023)·82 citations
06
[Submitted on 15 Dec 2021]
Ab-initio coupled-cluster calculations of ground and dipole excited states in 8He
Francesca Bonaiti · Sonia Bacca · Gaute Hagen
We perform coupled-cluster calculations of ground- and dipole excited-state properties of the 8He halo nucleus with nucleon-nucleon and three-nucleon interactions from chiral effective field theory, both with and without explicit delta degrees of freedom. By increasing the precision in our coupled-cluster calculations via the inclusion of leading order three-particle three-hole excitations in the cluster operator, we obtain a ground-state energy and a charge radius that are consistent with experiment, albeit with a slight under-binding. We also investigate the excited states induced by the electric dipole operator and present a discussion on the Thomas-Reiche-Kuhn and cluster sum rules. Finally, we compute the electric dipole polarizability, providing a theoretical benchmark for future experimental determinations that will study this exotic nucleus.
Comments:
10 pages, 6 figures, corrected typos in Eq. (11) and in Table V, version accepted for publication
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2112.08210 [pdf]
PRC(2022)·29 citations
07
[Submitted on 15 Dec 2021]
Gorkov algebraic diagrammatic construction formalism at third order
Carlo Barbieri (Milan, INFN-Milan)🇮🇹 · Thomas Duguet (CEA, KU Leuven)🇫🇷 · Vittorio Somà (CEA)🇫🇷
Background. The Gorkov approach to self-consistent Green's function theory has been formulated in [V. Somà, T. Duguet, C. Barbieri, Phys. Rev. C 84, 064317 (2011)]. Over the past decade, it has become a method of reference for first-principle computations of semi-magic nuclear isotopes. The currently available implementation is limited to a second-order self-energy and neglects particle-number non-conserving terms arising from contracting three-particle forces with anomalous propagators. For nuclear physics applications, this is sufficient to address first-order energy differences, ground-state radii and moments on an accurate enough basis. However, addressing absolute binding energies, fine spectroscopic details of $N \pm 1$ particle systems or delicate quantities such as second-order energy differences associated to pairing gaps, requires to go to higher truncation orders. Purpose. The formalism is extended to third order in the algebraic diagrammatic construction (ADC) expansion with two-body Hamiltonians. Methods. The expansion of Gorkov propagators in Feynman diagrams is combined with the algebraic diagrammatic construction up to the third order as an organization scheme to generate the Gorkov self-energy. Results. Algebraic expressions for the static and dynamic contributions to the self-energy, along with equations for the matrix elements of the Gorkov eigenvalue problem, are derived. It is first done for a general basis before specifying the set of equations to the case of spherical systems displaying rotational symmetry. Workable approximations to the full self-consistency problem are also elaborated on. The formalism at third order it thus complete for a general two-body Hamiltonian. Conclusion. Working equations for the full Gorkov-ADC(3) are now available for numerical implementation.
Comments:
30 pages, 8 figures; published version
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el); Superconductivity (cond-mat.supr-con)
arXiv:
2112.08322 [pdf]
PRC(2022)·33 citations

Affiliations

first authorsco-authorsvia INSPIRE

Dark matter component in hadronic models with short-range correlations

4α linear-chain state produced by 9Be+9Be collision

Neutrinoless double-beta decay: combining quantum Monte Carlo and the nuclear shell model with the generalized contact formalism

On the Photoproduction Reactions γd→πNN

Investigating Signatures of Phase Transitions in Neutron-Star Cores

Ab-initio coupled-cluster calculations of ground and dipole excited states in 8He

Gorkov algebraic diagrammatic construction formalism at third order

Affiliations

4 $α$ linear-chain state produced by $^{9}$ Be+ $^{9}$ Be collision

On the Photoproduction Reactions $γ d \to π N N$