Nuclear Theory·nucl-th

Tuesday·February 4, 2020

12 papers—9 primary·3 cross-listed

01
Local nucleon-nucleon and three-nucleon interactions within chiral effective field theory
Maria Piarulli🇺🇸 · Ingo Tews🇺🇸
To obtain an understanding of the structure and reactions of nuclear systems from first principles has been a long-standing goal of nuclear physics. In this respect, few- and many-body systems provide a unique laboratory for studying nuclear interactions. During the past decades, the development of accurate representations of the nuclear force has undergone substantial progress. Particular emphasis has been devoted to chiral effective field theory (EFT), a low-energy effective representation of quantum chromodynamics (QCD). Within chiral EFT, many studies have been carried out dealing with the construction of both the nucleon-nucleon ( $N N$ ) and three-nucleon ( $3 N$ ) interactions. The aim of the present article is to give a detailed overview of the chiral interaction models that are local in configuration space, and show recent results for nuclear systems obtained by employing these local chiral forces.
nucl-thFront.in Phys.(2020)·76 citations
02
Coupling of shape and pairing vibrations in a collective Hamiltonian based on nuclear energy density functionals
J. Xiang · Z. P. Li · T. Niksic · D. Vretenar · W. H. Long
The quadrupole collective Hamiltonian, based on relativistic energy density functionals, is extended to include a pairing collective coordinate. In addition to quadrupole shape vibrations and rotations, the model describes pairing vibrations and the coupling between shape and pairing degrees of freedom. The parameters of the collective Hamiltonian are determined by constrained self-consistent relativistic mean-field plus Bardeen-Cooper-Schrieffer (RMF+BCS) calculations in the space of intrinsic shape and pairing deformations. The effect of coupling between shape and pairing degrees of freedom is analyzed in a study of low-energy spectra and transition rates of four axially symmetric $N = 92$ rare-earth isotones. When compared to results obtained with the standard quadrupole collective Hamiltonian, the inclusion of dynamical pairing increases the moment of inertia, lowers the energies of excited $0^{+}$ states and reduces the E0-transition strengths, in better agreement with data.
nucl-thnucl-exPRC(2020)·21 citations
03
Dynamical simulation on production of $W^{\pm}$ and $Z^{0}$ bosons in p-p, p-Pb (Pb-p), and Pb-Pb collisions at $s_{NN} = 5.02$ TeV with PACIAE
Dai-Mei Zhou🇨🇳 · Yu-Liang Yan🇨🇳 · Liang Zheng🇨🇳 · Ming-Rui Zhao🇨🇳 · Xiao-Mei Li🇨🇳 · Xiao-Ming Zhang🇨🇳 · Xu Cai🇨🇳 · Ben-Hao Sa🇨🇳
In this paper, production of $W^{\pm}$ and $Z^{0}$ vector bosons in p-p, p-Pb (Pb-p), and Pb-Pb collisions at $s_{NN} = 5.02$ TeV is dynamically simulated with a parton and hadron cascade model PACIAE. ALICE data of $Z^{0}$ production is found to be reproduced fairly well. A prediction for $W^{\pm}$ production is given in the same collision systems, at the same energy and at the same energy. An interesting isospin-effect is observed in the sign-change of $μ^{\pm}$ charge asymmetry in pp, pn, np, and nn collisions and in minimum bias p-Pb, Pb-p and Pb-Pb collisions at $s_{NN} = 5.02$ TeV, respectively.
nucl-thhep-ph0 citations
04
Charm-hadron production in $pp$ and AA collisions
Min He🇨🇳 · Ralf Rapp🇺🇸
Recent measurements of various charm-hadron ratios in $pp$ , $p$ -Pb and Pb-Pb collisions at the LHC have posed challenges to the theoretical understanding of heavy-quark hadronization. The $Λ_{c} / D^{0}$ ratio in $pp$ and $p$ -Pb collisions shows larger values than those found in $e^{+} e^{-}$ and $e p$ collisions and predicted by Monte-Carlo event generators based on string fragmentation, at both low and intermediate transverse momenta ( $p_{T}$ ). In AA collisions, the $D_{s} / D$ ratio is significantly enhanced over its values in $pp$ , while the $Λ_{c} / D^{0}$ data indicates a further enhancement at intermediate $p_{T}$ . Here, we report on our recent developments for a comprehensive description of the charm hadrochemistry and transport in $pp$ and $AA$ collisions. For $pp$ collisions we find that the discrepancy between the $Λ_{c} / D^{0}$ data and model predictions is much reduced by using a statistical hadronization model augmented by a large set of "missing" states in the charm-baryon spectrum, contributing to the $Λ_{c}$ via decay feeddown. For $AA$ collisions, we develop a 4-momentum conserving resonance recombination model for charm-baryon formation implemented via event-by-event simulations that account for space-momentum correlations (SMCs) in transported charm- and thermal light-quark distributions. The SMCs, together with the augmented charm-baryon states, are found to play an important role in describing the baryon-to-meson enhancement at intermediate momenta. We emphasize the importance of satisfying the correct (relative) chemical equilibrium limit when computing the charm hadrochemistry and its momentum dependence with coalescence models.
nucl-thhep-phNPA(2021)·2 citations
05
Hyperon-nuclear interactions from SU(3) chiral effective field theory
Stefan Petschauer🇩🇪 · Johann Haidenbauer🇩🇪 · Norbert Kaiser🇩🇪 · Ulf-G. Meißner🇩🇪 · Wolfram Weise🇩🇪
The interaction between hyperons and nucleons has a wide range of applications in strangeness nuclear physics and is a topic of continuing great interest. These interactions are not only important for hyperon-nucleon scattering but also essential as basic input to studies of hyperon-nuclear few- and many-body systems including hypernuclei and neutron star matter. We review the systematic derivation and construction of such baryonic forces from the symmetries of quantum chromodynamics within non-relativistic SU(3) chiral effective field theory. Several applications of the resulting potentials are presented for topics of current interest in strangeness nuclear physics.
nucl-thFront.in Phys.(2020)·51 citations
06
Effects of symmetry energy on the radius and tidal deformability of neutron stars in relativistic mean-field model
Jinniu Hu · Shishao Bao · Ying Zhang · Ken'ichiro Nakazato · Kohsuke Sumiyoshi · Hong Shen
The radii and tidal deformabilities of neutron stars are investigated in the framework of relativistic mean-field (RMF) model with different density-dependent behaviors of symmetry energy. To study the effects of symmetry energy on the properties of neutron stars, an $ω$ meson and $ρ$ meson coupling term is included in a popular RMF Lagrangian, i.e. the TM1 parameter set, which is used for the widely used supernova equation of state (EoS) table. The coupling constants relevant to the vector-isovector meson, $ρ$ , are refitted by a fixed symmetry energy at subsaturation density and its slope at saturation density, while other coupling constants remain the same as the original ones in TM1 so as to update the supernova EoS table. The radius and mass of maximum neutron stars are not so sensitive to the symmetry energy in these family TM1 parameterizations. However, the radii at intermediate mass region are strongly correlated with the slope of symmetry energy. Furthermore, the dimensionless tidal deformabilities of neutron stars are also calculated within the associated Love number. We find that its value at $1.4 M_{⊙}$ has a linear correlation to the slope of symmetry energy being different from the previous studied. With the latest constraints of tidal deformabilities from GW170817 event, the slope of symmetry energy at nuclear saturation density should be smaller than $60$ MeV in the family TM1 parameterizations. This fact supports the usage of lower symmetry energy slope for the update supernova EoS, which is applicable to simulations of neutron star merger. Furthermore, the analogous analysis are also done within the family IUFSU parameter sets. It is found that the correlations between the symmetry energy slope with the radius and tidal deformability at $1.4 M_{⊙}$ have very similar linear relations in these RMF models.
nucl-thPTEP(2020)·40 citations
07
Effects of dark matter on the nuclear and neutron star matter
H. C. Das🇮🇳 · Ankit Kumar🇮🇳 · Bharat Kumar🇯🇵 · S. K. Biswal🇨🇳 · Takashi Nakatsukasa🇯🇵 · Ang Li🇨🇳 · S. K. Patra🇮🇳
We study the dark matter effects on the nuclear matter parameters characterising the equation of states of super dense neutron-rich nucleonic-matter. The observables of the nuclear matter, i.e. incompressibility, symmetry energy and its higher-order derivatives in the presence dark matter for symmetric and asymmetric nuclear matter are analysed with the help of an extended relativistic mean-field model. The calculations are also extended to beta-stable matter to explore the properties of the neutron star. We analyse the dark matter effects on symmetric nuclear matter, pure neutron matter and neutron star using NL3, G3 and IOPB-I forces. The binding energy per particle and pressure are calculated with and without considering the dark matter interaction with the nuclear matter systems. The influences of dark matter are also analysed on the symmetry energy and its different coefficients. The incompressibility and the skewness parameters are affected considerably due to the presence of dark matter in the nuclear matter medium. We extend the calculations to the neutron star and find its mass, radius and the moment of inertia for static and rotating neutron star with and without dark matter contribution. The mass of the rotating neutron star is considerably changing due to rapid rotation with the frequency in the mass-shedding limit. The effects of dark matter are found to be important for some of the nuclear matter parameters, which are crucial for the properties of astrophysical objects.
nucl-thastro-ph.HEhep-phMNRAS(2020)·115 citations
08
Constraining Bag constant for Hybrid Neutron stars
I. A. Rather🇮🇳 · A. Kumar🇮🇳 · H. C. Das🇮🇳 · M. Imran🇮🇳 · A. A. Usmani🇮🇳 · S. K. Patra🇮🇳
We study the star matter properties for Hybrid equation of state (EoS) by varying the bag constant. We use the Effective-Field-Theory motivated Relativistic Mean-Field model (E-RMF) for hadron phase with recently reported FSUGarnet, G3 and IOPB-I parameter sets. The result of NL3 and NL3 $ω ρ$ sets are also shown for comparison. The simple MIT Bag model is applied for the quark phase to construct the hybrid EoS. The hybrid neutron star mass and radius are calculated by varying with $B^{1/4}$ to constrain the $B^{1/4}$ values. It is found that $B^{1/4}$ =130-160 MeV is suitable for explaining the quark matter in neutron stars.
nucl-thIJMPE(2020)·12 citations
09
Beryllium-9 in Cluster Effective Field Theory
Elena Filandri · Paolo Andreatta · Carlo A. Manzata · Chen Ji · W. Leidemann · G. Orlandini
We study the 9 Be ground-state energy with non-local $α -$ n and $α - α$ potentials derived from Cluster Effective Field Theory. The short-distance dependence of the interaction is regulated with a momentum cutoff. The potential parameters are fitted to reproduce the scattering length and effective range. We implement such potential models in a Non-Symmetrized Hyperspherical Harmonics (NSHH) code in momentum space. In addition we calculate ground state energies of various alpha nuclei. Work is in progress on a calculation of the photodisintegration of 9Be with the Lorentz Integral Transform (LIT) method.
nucl-thSciPost Phys.Proc.(2020)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE