Nuclear Theory·nucl-th

Tuesday·March 8, 2022

11 papers—4 primary·7 cross-listed

01
Theory of nuclear collective vibrations
Haozhao Liang · Elena Litvinova
We review the theory of nuclear collective vibrations evolved over decades from phenomenological quasiclassical picture to sophisticated microscopic approaches. The major focus is put on the underlying microscopic mechanisms of emergent effects, which define the properties of giant resonances and soft modes. The response of atomic nuclei to electromagnetic and weak fields is discussed in detail. Astrophysical implications of the giant resonances and soft modes are outlined.
nucl-th0 citations
02
The nuclear symmetry energy from relativistic Brueckner-Hartree-Fock model
Chencan Wang · Jinniu Hu · Ying Zhang · Hong Shen
The microscopic mechanisms of the symmetry energy in nuclear matter are investigated in the framework of the relativistic Brueckner-Hartree-Fock (RBHF) model with a high-precision realistic nuclear potential, pvCDBonn A. The kinetic energy and potential contributions to symmetry energy are decomposed. They are explicitly expressed by the nucleon self-energies, which are obtained through projecting the $G$ -matrices from the RBHF model into the terms of Lorentz covariants. The nuclear medium effects on the nucleon self-energy and nucleon-nucleon interaction in symmetry energy are discussed by comparing the results from the RBHF model and those from Hartree-Fock and relativistic Hartree-Fock models. It is found that the nucleon self-energy including the nuclear medium effect on the single-nucleon wave function provides a largely positive contribution to the symmetry energy, while {the nuclear medium effect on the nucleon-nucleon interaction, i.e., the effective $G$ -matrices generates the negative contribution}. The tensor force plays an essential role in the symmetry energy around the density. The scalar and vector covariant amplitudes of nucleon-nucleon interaction dominate the potential component of the symmetry energy. Furthermore, the isoscalar and isovector terms in the optical potential are extracted from the RBHF model. The isoscalar part is consistent with the results from the analysis of global optical potential, while the isovector one has obvious differences at higher incident energy due to the relativistic effect.
nucl-thCPC(2022)·6 citations
03
Seniority and $(\frac{9}{2})^{n}$ configurations in neutron-rich Nickel isotopes
S. Sidorov · D. Zhulyaeva · T. Tretyakova
Excited states in low-energy spectra in $^{70 - 76}$ Ni are considered. To this end, pairing forces in form of surface delta interaction are employed to account for formation of the ground state multiplet with seniority $ν = 2$ states. The multiplet splitting is described with mass relations of masses of neighbouring nuclei. Subsequently, seniority model is used to reproduce or predict the states $ν = 3$ in odd-even isotopes and $ν = 4$ in even-even isotopes. Correct account of $2_{1}^{+}$ state should allow for description of reversed order of states $J = 4$ with $ν = 2$ and $ν = 4$ observed in experiment. The results obtained are compared with the structure of similar multiplets in $N = 50$ isotones.
nucl-thnucl-exCPC(2022)·3 citations
04
Charge radii of Ca isotopes and correlations
G. Co' · M. Anguiano · A. M. Lallena
We study the effects of short- and long-range correlations on the charge radii of Ca isotopes. We start our investigation with an independent particle model consisting in Hartree-Fock plus Bardeen-Cooper-Schrieffer calculations with finite-range effective nucleon-nucleon interactions of Gogny type. The short-range correlations effects are evaluated by considering all the terms of a cluster expansion containing a single correlation line. The long-range correlations are taken into account by including the coupling with the quasi-particle random phase approximation phonons. While the effects of the short-range correlations are negligible, those of the long-range correlations largely modify the independent particle model results and improve the agreement with the experimental data.
nucl-thPRC(2022)·10 citations
05
The Status and Future of Color Transparency and Nuclear Filtering
P. Jain🇮🇳 · B. Pire🇫🇷 · J.P. Ralston🇺🇸
40 years after its introduction, the phenomenon of color transparency remains a domain of controversial interpretations of experimental data. We review present evidence for or against its manifestation in various exclusive hard scattering reactions. The nuclear transparency experiments reveal whether short distance processes dominate a scattering amplitude at some given kinematical point. We plead for a new round of nuclear transparency measurements in a variety of experimental set-ups, including near-forward exclusive reactions related to generalized parton distribution (GPD) physics and near-backward exclusive reactions related to transition distribution amplitudes (TDA) physics.
↳ hep-phhep-exnucl-thMDPI Physics(2022)·9 citations
06
Progress in understanding short-range structure in nuclei: an experimental perspective
John Arrington🇺🇸 · Nadia Fomin🇺🇸 · Axel Schmidt🇺🇸
High-energy electron scattering is a clean and precise probe for measurements of hadronic and nuclear structure, with a key role in understanding the role of high-momentum nucleons (and quarks) in nuclei. Jefferson Lab has dramatically expanded our understanding of the high-momentum nucleons generated by short-range correlations, providing sufficient insight to model much of their impact on nuclear structure in neutron stars, and in low- to medium-energy scattering observables including neutrino oscillation measurements. These short-range correlations also appear to be related to the modification of the quark distributions in nuclei, and efforts to improve our understanding of the internal structure of these short-distance and high-momentum configurations in nuclei will provide important input on a wide range of high-energy observables.
↳ nucl-exnucl-thAnn.Rev.Nucl.Part.Sci.(2022)·62 citations
07
Consequences of neutron decay inside neutron stars
Wasif Husain🇦🇺 · Theo F. Motta🇦🇺 · Anthony W. Thomas🇦🇺
The hypothesis that neutrons might decay into dark matter is explored using neutron stars as a testing ground. It is found that in order to obtain stars with masses at the upper end of those observed, the dark matter must experience a relatively strong self-interaction. Conservation of baryon number and energy then require that the star must undergo some heating, with a decrease in radius, leading to an increase in speed of rotation over a period of days.
↳ hep-phnucl-thJCAP(2022)·42 citations
08
Entanglement and correlations in fast collective neutrino flavor oscillations
Alessandro Roggero🇺🇸 · Ermal Rrapaj🇺🇸 · Zewei Xiong🇩🇪
Collective neutrino oscillations play a crucial role in transporting lepton flavor in astrophysical settings like supernovae and neutron star binary merger remnants, which are characterized by large neutrino densities. In these settings, simulations in the mean-field approximation show that neutrino-neutrino interactions can overtake vacuum oscillations and give rise to fast collective flavor evolution on time-scales $t \propto μ^{- 1}$ , with $μ$ proportional to the local neutrino density. In this work, we study the full out-of-equilibrium flavor dynamics in simple multi-angle geometries displaying fast oscillations in the mean field linear stability analysis. Focusing on simple initial conditions, we analyze the production of pair correlations and entanglement in the complete many-body-dynamics as a function of the number $N$ of neutrinos in the system, for up to thousands of neutrinos. Similarly to simpler geometries with only two neutrino beams, we identify three regimes: stable configurations with vanishing flavor oscillations, marginally unstable configurations with evolution occurring on long time scales $τ \approx μ^{- 1} N$ , and unstable configurations showing flavor evolution on short time scales $τ \approx μ^{- 1} lo g (N)$ . We present evidence that these fast collective modes are generated by the same dynamical phase transition which leads to the slow bipolar oscillations, establishing a connection between these two phenomena and explaining the difference in their time scales. We conclude by discussing a semi-classical approximation which reproduces the entanglement entropy at short to medium time scales and can be potentially useful in situations with more complicated geometries where classical simulation methods starts to become inefficient.
↳ astro-ph.HEnucl-thquant-phPRD(2022)·53 citations
09
General relativistic treatment of $f$ -mode oscillations of hyperonic stars
Bikram Keshari Pradhan (1) · Debarati Chatterjee (1) · Michael Lanoye (2) · Prashanth Jaikumar (2) ((1) Inter-University Center for Astronomy and Astrophysics, pune,411007, India, (2) California State University Long Beach, Long Beach, California 90840 U.S.A.)
We present a systematic study of $f$ -mode oscillations in neutron stars containing hyperons, extending recent results obtained within the Cowling approximation to linearized General Relativity. Employing a relativistic mean field model, we find that the Cowling approximation can overestimate the quadrupolar $f$ -mode frequency of neutron stars by up to 30\% compared to the frequency obtained in the linearized general relativistic formalism. Imposing current astrophysical constraints, we derive updated empirical relations for gravitational wave asteroseismology. The frequency and damping time of quadrupole $f$ -mode oscillations of hyperonic stars are found to be in the range of 1.47 - 2.45kHz and 0.13 - 0.51 sec respectively. Our correlation studies demonstrate that among the various parameters of the nucleonic and hyperonic sectors of the model, the nucleon effective mass shows the strongest correlation with mode characteristics and neutron star observables. Estimates for the detectability of $f$ -modes in a transient burst of gravitational waves from isolated hyperonic stars is also provided.
↳ astro-ph.HEgr-qcnucl-thPRC(2022)·80 citations
10
Multi-physics constraints at different densities to probe nuclear symmetry energy in hyperonic neutron stars
Suprovo Ghosh🇮🇳 · Bikram Keshari Pradhan🇮🇳 · Debarati Chatterjee🇮🇳 · Jürgen Schaffner-Bielich🇩🇪
The appearance of strangeness in the form of hyperons within the inner core of neutron stars is expected to affect its detectable properties such as its global structure or gravitational wave emission. In this work, we explore the parameter space of hyperonic stars within the framework of the Relativistic Mean Field model allowed by present uncertainties in state-of-the-art nuclear and hypernuclear experimental data. We impose multi-physics constraints at different density regimes to restrict the parameter space: Chiral effective field theory, heavy-ion collision data as well as multi-messenger astrophysical observations of neutron stars. We investigate possible correlations between empirical nuclear and hypernuclear parameters, particularly the symmetry energy and its slope, with observable properties of neutron stars. We do not find a correlation for the hyperon parameters and the astrophysical data. However, the inclusion of hyperons generates a tension between the astrophysical and heavy ion data constraining considerable the available parameter space.
↳ astro-ph.HEnucl-thFront.Astron.Space Sci.(2022)·52 citations
11
CompOSE Reference Manual
S. Typel🇩🇪 · M. Oertel🇫🇷 · T. Klähn🇺🇸 · D. Chatterjee🇮🇳 · V. Dexheimer🇺🇸 · C. Ishizuka🇯🇵 · M. Mancini🇫🇷 · J. Novak🇫🇷 · H. Pais🇵🇹 · C. Providencia🇵🇹 · A. Raduta🇷🇴 · M. Servillat🇫🇷 · L. Tolos🇪🇸
CompOSE (CompStar Online Supernovae Equations of State) is an online repository of equations of state (EoS) for use in nuclear physics and astrophysics, e.g., in the description of compact stars or the simulation of core-collapse supernovae and neutron-star mergers, see http://compose.obspm.fr. The main services, offered via the website, are: a collection of data tables in a flexible and easily extendable data format for different EoS types and related physical quantities with extensive documentation and referencing; software for download to extract and to interpolate these data and to calculate additional quantities; webtools to generate EoS tables that are customized to the needs of the users and to illustrate dependencies of various EoS quantities in graphical form. This manual is an update of previous versions that are available on the CompOSE website, at arXiv:1307.5715 [astro-ph.SR], and that was originally published in the journal "Physics of Particles and Nuclei" with doi:10.1134/S1063779615040061. It contains a detailed description of the service, containing a general introduction as well as instructions for potential contributors and for users. Short versions of the manual for EoS users and providers will also be available as separate publications.
↳ astro-ph.HEnucl-thEPJA(2022)·144 citations

Affiliations

first authorsco-authorsvia INSPIRE