Nuclear Theory·nucl-th

Wednesday·October 17, 2018

12 papers—6 primary·6 cross-listed

01
[Submitted on 16 Oct 2018]
Squeezed back-to-back correlation between bosons and antibosons with different in-medium masses in high-energy heavy-ion collisions
Peng-Zhi Xu🇨🇳 · Wei-Ning Zhang🇨🇳 · Yong Zhang🇨🇳
We derive the formulas of the squeezed back-to-back correlation (SBBC) between a boson and antiboson with different in-medium masses in high-energy heavy-ion collisions. The influence of the in-medium mass difference between a boson and antiboson on the SBBC is investigated. We calculate the SBBC functions of $D$ -meson pairs for the hydrodynamic sources described by the VISH2+1 code for Au+Au collisions at $s_{N N} = 200$ ~GeV. Our results indicate that the SBBC strengths of $D^{+} D^{-}$ and $D^{0} D ˉ^{0}$ are different if there are charge-dependent in-medium interactions.
Comments:
5 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1810.06782 [pdf]
PRC(2019)·14 citations
02
[Submitted on 16 Oct 2018]
Symmetry-Based Approach to Shape Coexistence in Nuclei
A. Leviatan🇮🇱 · N. Gavrielov🇮🇱
A symmetry-based approach for describing shape-coexistence, is presented in the framework of the interacting boson model of nuclei. It involves a construction of a number-conserving Hamiltonian which preserves the dynamical symmetry of selected bands associated with each shape, while breaking the symmetries in other states. The resulting structure embodies multiple partial dynamical symmetries. The procedure is applied to prolate-oblate and spherical-prolate-oblate coexistence, at and slightly away from the critical points.
Comments:
12 pages, 5 figures, Final version, Proc. Int. Workshop on "Shapes and Dynamics of Atomic Nuclei: Contemporary Aspects" (SDANCA-17), October 5-7, 2017, Sofia, Bulgaria. arXiv admin note: substantial text overlap with arXiv:1708.06321, arXiv:1803.03982, arXiv:1605.00782
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1810.06804 [pdf]
Bulg.J.Phys.(2018)·0 citations
03
[Submitted on 16 Oct 2018]
Extrapolation of scattering data to the negative-energy region. Application to the $p -^{16}$ O system
L. D. Blokhintsev · A. S. Kadyrov · A. M. Mukhamedzhanov · D. A. Savin
The problem of analytic continuation of the scattering data to the negative-energy region to obtain information on asymptotic normalization coefficients (ANCs) of bound states is discussed. It is shown that a recently suggested $Δ$ method [O.L.Ram\'ırez Suárez and J.-M. Sparenberg, Phys. Rev. C {\bf 96}, 034601 (2017)] is not strictly correct in the mathematical sense since it is not an analytic continuation of a partial-wave scattering amplitude to the region of negative energies. However, it can be used for practical purposes for sufficiently large charges and masses of colliding particles. Both the $Δ$ method and the standard method of continuing of the effective range function are applied to the $p -^{16}$ O system which is of interest for nuclear astrophysics. The ANCs for the ground $5/ 2^{+}$ and excited $1/ 2^{+}$ states of $^{17}$ F are determined.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1810.06812 [pdf]
PRC(2018)·13 citations
04
[Submitted on 14 Oct 2018]
Effects of $Δ (1905) 5/ 2^{+}$ on $K^{*} Σ$ photoproduction
A. C. Wang🇨🇳 · W. L. Wang🇨🇳 · F. Huang🇨🇳
The two-channel photoproductions of $γ p \to K^{*+} Σ^{0}$ and $γ p \to K^{* 0} Σ^{+}$ are investigated based on an effective Lagrangian approach at the tree-level Born approximation. In addition to the $t$ -channel $K$ , $κ$ , $K^{*}$ exchanges, the $s$ -channel nucleon ( $N$ ) and $Δ$ exchanges, the $u$ -channel $Λ$ , $Σ$ , $Σ^{*}$ exchanges, and the generalized contact term, we try to take into account the minimum number of baryon resonances in constructing the reaction amplitudes to describe the experimental data. It is found that by including the $Δ (1905) 5/ 2^{+}$ resonance with its mass, width, and helicity amplitudes taken from the Review of Particle Physics [Particle Data Group, C. Patrignani {\it et al.}, Chin. Phys. C {\bf 40}, 100001 (2016)], the calculated differential and total cross sections for these two reactions are in good agreement with the experimental data. An analysis of the reaction mechanisms shows that the cross sections of $γ p \to K^{*+} Σ^{0}$ are dominated by the $s$ -channel $Δ (1905) 5/ 2^{+}$ exchange at low energies and $t$ -channel $K^{*}$ exchange at high energies, with the $s$ -channel $Δ$ exchange providing significant contributions in the near-threshold region. For $γ p \to K^{* 0} Σ^{+}$ , the angular dependences are dominated by the $t$ -channel $K$ exchange at forward angles and the $u$ -channel $Σ^{*}$ exchange at backward angles, with the $s$ -channel $Δ$ and $Δ (1905) 5/ 2^{+}$ exchanges making considerable contributions at low energies. Predictions are given for the beam, target, and recoil asymmetries for both reactions.
Comments:
11 pages, 8 figures, version published in PRC. arXiv admin note: text overlap with arXiv:1704.04562
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1810.07012 [pdf]
PRC(2018)·29 citations
05
[Submitted on 16 Oct 2018]
Can magnetic fields stabilize or destabilize twin stars?
R.O. Gomes🇩🇪 · V. Dexheimer🇺🇸 · S. Han🇺🇸 · S. Schramm🇩🇪
Sharp phase transitions described by stiff equations of state allow for the existence of a third family of stable compact stars (besides white dwarfs and neutron stars), twin stars. In this work, we investigate for the first time the role of strong magnetic fields on non-magnetic twin stars sequences and the case in which magnetic fields themselves give rise to a third family of stable stars. We use three sets of equations of state to study such effects from a more general point of view: the Quark-Hadron Chiral Parity-Doublet (Q $χ$ P) model for both hadronic and quark phases, and the Many-Body Forces (MBF) model connected to either the MIT Bag model with vector interaction (MIT) or to the Constant-Sound-Speed (CSS) approximation for the quark phase, through a Maxwell construction. Magnetic field effects are introduced in the structure of stars through the solution of the Einstein-Maxwell equations, assuming a poloidal magnetic field configuration and a metric that allows for the description of deformed stars. We show that strong magnetic fields can destabilize twin star sequences, with the threshold intensity being model dependent. On the other hand, magnetic fields can also give rise to twin stars in models that did not predict these sequences, up to some point when they are again destabilized. In this sense, magnetic fields can play an important role on the evolution of neutron stars.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
1810.07046 [pdf]
MNRAS(2019)·29 citations
06
[Submitted on 16 Oct 2018]
Spin response and neutrino mean free path in neutron matter
Luca Riz🇮🇹 · Francesco Pederiva🇮🇹 · Stefano Gandolfi🇺🇸
The longitudinal and transverse density- and spin-density response functions in Pure Neutron Matter (PNM) are derived over a wide range of densities within the Time Dependent Local Spin Density Approximation (TDLSDA). The underlying density functional was derived from an Auxiliary Field Diffusion Monte Carlo (AFDMC) computation of the equation of state of unpolarized and fully spin polarized pure neutron matter. In order to assess the dependence of the results on the specific underlying nucleon-nucleon Hamiltonian, we used both the phenomenological Argonne AV8'+UIX force, and local chiral forces up to N2LO. The resulting response function has then been applied to the study of the neutrino mean free path in PNM.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
1810.07110 [pdf]
J.Phys.G(2020)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE

Squeezed back-to-back correlation between bosons and antibosons with different in-medium masses in high-energy heavy-ion collisions

Symmetry-Based Approach to Shape Coexistence in Nuclei

Extrapolation of scattering data to the negative-energy region. Application to the p−16O system

Effects of Δ(1905)5/2+ on K∗Σ photoproduction

Can magnetic fields stabilize or destabilize twin stars?

Spin response and neutrino mean free path in neutron matter

Affiliations

Extrapolation of scattering data to the negative-energy region. Application to the $p -^{16}$ O system

Effects of $Δ (1905) 5/ 2^{+}$ on $K^{*} Σ$ photoproduction