Nuclear Theory·nucl-th

Monday·August 14, 2017

7 papers—5 primary·2 cross-listed

01
A microscopic cranking model for uni-axial rotation with vanishing collective angular momentum
Parviz Gulshani
The rigid-irrotational flow transformation in the previous microscopic cranking model (MCRM) for nuclear collective rotation about a single axis and its coupling to intrinsic motion is generalized. This generalization allow us to consider the limit of vanishingly small collective angular velocity and hence collective angular momentum while the collective moment of inertia remains finite. In this limit, the collective flow become large and oppose one another collaborating the vanishing of the collective angular momentum. In this limit, the MCRM equation for the angular-momentum constraint on the intrinsic wavefunction becomes identical to that of the conventional cranking model (CCRM). In this limit, the MCRM Schrodinger equation also becomes identical to that of the CCRM with an added irrotational-flow kinetic energy component. In this limit, the time-reversal invariance of the MCRM Schrodinger equation is destroyed. The two MCRM equations (with no free parameters) are solved for the ground-state rotational band in the nucleus for a simple deformed harmonic oscillator potential. The predicted excitation energy and quadrupole moment are close to those observed empirically, with the differences seemingly attributable to the absence, in the model, of pairing correlations at low angular momenta and Coriolis-force induced quasi-particle rotation alignment at higher angular momenta. The ground-state terminal (cut-off) angular momentum is predicted to be 10 instead of 8 observed empirically and predicted by the CCRM. It is assumed that pairing correlations would reduce the cut-off angular momentum.
nucl-th2 citations
02
Universal physics of the few-body system of two neutrons and one flavored meson
Udit Raha🇮🇳 · Yuki Kamiya🇯🇵 · Shung-Ichi Ando🇰🇷 · Tetsuo Hyodo🇯🇵
We investigate the $s$ -wave three-body system of two neutrons and one flavored meson with total spin-isospin $J = 0, I = 3/2$ . The meson-neutron scattering length can become infinitely large in an unphysical region of the quark mass when extrapolated from strangeness to charm in the so-called zero coupling limit. Using a low-energy cluster effective field theory, we demonstrate that the Efimov effect is manifest in the three-body system when the meson-neutron scattering length is extrapolated to the unitary limit of the two-body interaction. We thereby discuss the consequence of universal physics in the physical $K^{-} nn$ and $D^{0} nn$ systems.
nucl-thhep-phPRC(2018)·9 citations
03
Warm asymmetric quark matter and proto-quark stars within the confined-isospin-density-dependent mass model
Peng-Cheng Chu🇨🇳 · Lie-Wen Chen🇨🇳
We extend the confined-isospin-density-dependent mass (CIDDM) model to include temperature dependence of the equivalent mass for quarks. Within the CIDDM model, we study the equation of state (EOS) for $β$ -equilibrium quark matter, quark symmetry energy, quark symmetry free energy, and the properties of quark stars at finite temperature. We find that including the temperature dependence of the equivalent mass can significantly influence the properties of the strange quark matter (SQM) as well as the quark symmetry energy, the quark symmetry free energy, and the maximum mass of quark stars at finite temperature. The mass-radius relations for different stages of the proto-quark stars (PQSs) along the star evolution are analyzed. Our results indicate that the heating (cooling) process for PQSs will increase (decrease) the maximum mass within CIDDM model by including temperature dependence of the equivalent mass for quarks.
nucl-thhep-phPRD(2017)·22 citations
04
On the nucleons motion in the nucleus as being due to realistic inter-nucleonic forces
Yuriy Lyakhno
This paper deals with the possible motion of nucleons in the nucleus, which is due to realistic inter-nucleonic forces. This approach provides new or more substantiated conclusions about the nuclear structure than those based on the effective interaction of nucleons, while the shell model of the nucleus may lead to questionable conclusions regarding the nuclear structure and nuclear reaction mechanisms.
nucl-thnucl-ex0 citations
05
Light vector and axial mesons effective couplings to constituent quarks
Fabio L Braghin🇧🇷
Low energy effective couplings of baryons' constituent quarks to light vector and axial mesons are derived by considering quark polarization for a dressed one gluon exchange quark interaction. The quark field is splitted into two components, one for background constituent quarks and another one for quark-antiquark states, light mesons and the scalar chiral condensate. By considering a large quark effective mass derivative expansion, several effective coupling constants are resolved as functions of the original model parameters and of components of the quark and gluon propagators. Besides the leading single vector meson-constituent quark gauge-type effective coupling, several two-vector and axial mesons-constituent quark couplings are also obtained in the next leading order. Among these, vector and axial mesons mixings induced by constituent quark currents are found.Approximated and exact ratios between the effective coupling constants in the limit of very large quark effective mass and numerical estimates are exhibited. Numerical results of the corresponding form factors and of the (strong) vector meson quadratic radius are also presented.
nucl-thhep-phPRD(2018)·10 citations
06
Pygmy and core polarization dipole modes in $^{206}$ Pb: connecting nuclear structure to stellar nucleosynthesis
A.P. Tonchev🇺🇸 · N. Tsoneva🇩🇪 · C. Bhatia🇮🇳 · C.W. Arnold🇺🇸 · S. Goriely🇧🇪 · S.L. Hammond🇺🇸 · J.H. Kelley🇺🇸 · E. Kwan🇺🇸 · H. Lenske🇩🇪 · J. Piekarewicz🇺🇸 · R. Raut🇮🇳 · G. Rusev🇺🇸 · T. Shizuma🇯🇵 · W. Tornow🇺🇸
A high-resolution study of the electromagnetic response of $^{206}$ Pb below the neutron separation energy is performed using a ( $γ$ , $γ^{'}$ ) experiment at the HI $γ$ S facility. Nuclear resonance fluorescence with 100% linearly polarized photon beams is used to measure spins, parities, branching ratios, and decay widths of excited states in $^{206}$ Pb from $4.9$ to $8.1$ MeV. The extracted $Σ$ $B$ (E1) $↑$ and $Σ$ $B$ (M1) $↑$ values for the total electric and magnetic dipole strength below the neutron separation energy are 0.9 $\pm$ 0.2e $^{2}$ fm $^{2}$ and 8.3 $\pm$ 2.0 $μ_{N}^{2}$ , respectively. These measurements are found to be in very good agreement with the predictions from an energy-density functional (EDF) plus quasiparticle phonon model (QPM). Such a detailed theoretical analysis allows to separate the pygmy dipole resonance from both the tail of the giant dipole resonance and multi-phonon excitations. Combined with earlier photonuclear experiments above the neutron separation energy, one extracts a value for the electric dipole polarizability of $^{206}$ Pb of $α_{D} = 122 \pm 10$ mb/MeV. When compared to predictions from both the EDF+QPM and accurately calibrated relativistic EDFs, one deduces a range for the neutron-skin thickness of $R_{skin}^{206} = 0.12$ - $0.19$ fm and a corresponding range for the slope of the symmetry energy of $L = 48$ - $60$ MeV. This newly obtained information is also used to estimate the Maxwellian-averaged radiative cross section $^{205}$ Pb(n, $γ$ ) $^{206}$ Pb at 30keV to be $σ = 130 \pm 25$ mb. The astrophysical impact of this measurement--on both the s-process in stellar nucleosynthesis and on the equation of state of neutron-rich matter--is discussed.
↳ nucl-exnucl-thPLB(2017)·50 citations
07
Radiative decays of the doubly charmed baryons in chiral perturbation theory
Hao-Song Li🇨🇳 · Lu Meng🇨🇳 · Zhan-Wei Liu🇨🇳 · Shi-Lin Zhu🇨🇳
We have systematically investigated the spin- $\frac{3}{2}$ to spin- $\frac{1}{2}$ doubly charmed baryon transition magnetic moments to the next-to-next-to-leading order in the heavy baryon chiral perturbation theory (HBChPT). Numerical results of transition magnetic moments and decay widths are presented to the next-to-leading order: $μ_{Ξ_{cc}^{*++} \to Ξ_{cc}^{++}} = - 2.35 μ_{N}$ , $μ_{Ξ_{cc}^{*+} \to Ξ_{cc}^{+}} = 1.55 μ_{N}$ , $μ_{Ω_{cc}^{*+} \to Ω_{cc}^{+}} = 1.54 μ_{N}$ , $Γ_{Ξ_{cc}^{*++} \to Ξ_{cc}^{++}} = 22.0$ keV, $Γ_{Ξ_{cc}^{*+} \to Ξ_{cc}^{+}} = 9.57$ keV, $Γ_{Ω_{cc}^{*+} \to Ω_{cc}^{+}} = 9.45$ keV.
↳ hep-phhep-exhep-latnucl-thPLB(2018)·86 citations

Affiliations

first authorsco-authorsvia INSPIRE

A microscopic cranking model for uni-axial rotation with vanishing collective angular momentum

Universal physics of the few-body system of two neutrons and one flavored meson

Warm asymmetric quark matter and proto-quark stars within the confined-isospin-density-dependent mass model

On the nucleons motion in the nucleus as being due to realistic inter-nucleonic forces

Light vector and axial mesons effective couplings to constituent quarks

Pygmy and core polarization dipole modes in 206Pb: connecting nuclear structure to stellar nucleosynthesis

Radiative decays of the doubly charmed baryons in chiral perturbation theory

Affiliations

Pygmy and core polarization dipole modes in $^{206}$ Pb: connecting nuclear structure to stellar nucleosynthesis