Nuclear Theory·nucl-th

Tuesday·September 11, 2018

14 papers—9 primary·5 cross-listed

01
[Submitted on 7 Sept 2018]
Study of various few-body systems using Gaussian expansion method (GEM)
Emiko Hiyama🇯🇵 · Masayasu Kamimura🇯🇵
We review our calculation method, Gaussian expansion method (GEM), and its applications to various few-body (3- to 5-body) systems such as 1) few-nucleon systems, 2) few-body structure of hypernuclei, 3) clustering structure of light nuclei and unstable nuclei, 4) exotic atoms/molecules, 5) cold atoms, 6) nuclear astrophysics and 7) structure of exotic hadrons. Showing examples in our published papers, we explain i) high accuracy of GEM calculations and its reason, ii) wide applicability of GEM and iii) successful predictions by GEM calculations before measurements. GEM was proposed 30 years ago and has been applied to a variety of subjects. To solve few-body Schroedinger equations accurately, use is made of the Rayleigh-Ritz variational method for bound states, the complex-scaling method for resonant states and the Kohn-type variational principle to S-matrix for scattering states. The total wave function is expanded in terms of few-body Gaussian basis functions spanned over all the sets of rearrangement Jacobi coordinates. Gaussians with ranges in geometric progression work very well both for short-range and long-range behavior of the few-body wave functions. Use of Gaussians with complex ranges gives much more accurate solution when the wave function has many oscillations.
Comments:
30 pages, 46 figures, an invited review paper for the international symposium in honor of Prof. Akito Arima for his 88th birthday, to be published in Frontiers of Physics, Vol.13 (2018)
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Atomic Physics (physics.atom-ph); physics.chem-ph (physics.chem-ph)
arXiv:
1809.02619 [pdf]
Front.Phys.(Beijing)(2018)·39 citations
02
[Submitted on 7 Sept 2018]
Evaluation of particle--anti-particle scaled correlation within effective models
Andre Garcia🇧🇷 · Volker Koch🇺🇸 · Marcus Benghi Pinto🇧🇷
Correlations and fluctuations of physical quantities are known to play an important role in phase transitions and critical phenomena. In recent years some experimental attempts were made in the scope of the Beam Energy Scan program to locate a possible critical point in the QCD phase diagram. In this work we use the Nambu--Jona-Lasinio model to investigate the off-diagonal quark susceptibility, which is related to the quark--anti-quark scaled correlation at the mean field level. We show that this correlation has a significant peak near the critical point and, therefore, may be a useful quantity to measure in experiment. We further study the effects of a repulsive vector coupling, which reduces the strength of the scaled correlation near the critical point.
Comments:
17 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1809.02655 [pdf]
NPA(2020)·3 citations
03
[Submitted on 8 Sept 2018]
Calculation Energy levels and charge radius for odd $^{41 - 49}$ Ca Isotopes by using the analytical approach
Mohsen Mousavi · Mohammad Reza Shojaei
In the present study, some static properties of odd isotopes of Ca were investigated in the non-relativistic shell model. We also suggested a novel suitable local potential model for the non-microscopic investigation of the mentioned nuclei. We modeled the odd $^{41 - 49}$ Ca nuclei as doubly-magic isotopes, with further nucleons (valence) in the lf7/2 and 2p3/2 levels. Then the modified Eckart potential as well as Hulthen potential were chosen for the interaction between core and nucleons. We also used the Parametric Nikiforov Uvarov method to calculate the values of energy, the radius of charge and wave function. The obtained results showed a good agreement with the experimental data, so this model is applicable for the similar nuclei.
Comments:
8 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1809.02774 [pdf]
Mod.Phys.Lett.A(2019)·4 citations
04
[Submitted on 10 Sept 2018]
Squeezed back-to-back correlations of $K^{+}$ $K^{-}$ in d+Au collisions at $s_{N N} = 200$ GeV and Au+Au collisions at $s_{N N} = 62.4$ GeV
Yong Zhang🇨🇳 · Jing Yang🇨🇳 · WeiHua Wu
We investigate the squeezed back-to-back correlations (BBC) of $K^{+}$ $K^{-}$ , caused by the mass modification of the particle in the dense medium formed in d+Au collisions at $s_{N N} = 200$ GeV and Au+Au collisions at $s_{N N} = 62.4$ GeV. Considering some kaons may be not affected by the medium, we further study the BBC functions of $K^{+}$ $K^{-}$ when parts of all kaons have a mass-shift. Our results indicate that the BBC functions of $K^{+}$ $K^{-}$ can be observed when only about 10 $%$ of all kaons have a mass-shift in d+Au collisions at $s_{N N} = 200$ GeV and the peripheral collisions of Au+Au at $s_{N N} = 62.4$ GeV. Since the BBC function is caused by the mass-shift due to the interaction between the particle and the medium, the successful detection of the BBC function indirectly marks that the dense medium has formed in these collision systems. We suggest to measure the BBC function of $K^{+}$ $K^{-}$ experimentally in d+Au collisions at $s_{N N} = 200$ GeV and peripheral collisions of Au+Au at $s_{N N} = 62.4$ GeV.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1809.03092 [pdf]
CPC(2019)·1 citation
05
[Submitted on 10 Sept 2018]
Spectator partons contribution in the rapidity width of lamda in p+p collisions at various SPS and LHC energies
Nur Hussain🇮🇳 · Banajit Barman · Buddhadeb Bhattacharjee🇮🇳
Pseudorapidity distributions of all primary charged particles produced in p+p collisions at various Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies using UrQMD-3.4 and PYTHIA8.2-generated events are estimated and compared with the existing results of UA5 and ALICE collaborations. With both the sets of generated data, the variation of rapidity widths with the rest masses of different mesons and baryons of p+p collisions at various Super Proton Synchrotron (SPS) and LHC energies are presented. An increase in the width of the rapidity distribution of lambda, similar to heavy-ion data, could be seen in p+p collisions as well from SPS to the LHC energies (up to {sqrt_s} =13 TeV) when the entire rapidity space is considered, indicating its universal feature both in p+p and A+A collisions. The genesis of the increased width of rapidity distribution of Lambda in p+p collision is found to be in the production of light flavored quarks and diquarks from the spectator partons of the colliding hadrons resulting {lambda}/{anti_lambda}>1 at the extreme rapidities of the studied p+p collisions. At the LHC energies for central p+p collision, when there is no spectator partons, the rapidity width of {lambda} is found to take the same Gaussian shape as that of lambda and the widths of both the distributions become the same confirming no non-trivial contribution to the rapidity width of {lambda} as seen in heavy-ion and non-central p+p collisions.
Comments:
11 Figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1809.03161 [pdf]
2 citations
06
[Submitted on 10 Sept 2018]
Strangeness $S = - 2$ baryon-baryon interactions in relativistic chiral effective field theory
Kai-Wen Li🇨🇳 · Tetsuo Hyodo🇯🇵 · Li-Sheng Geng🇨🇳
We study the strangeness $S = - 2$ baryon-baryon interactions in relativistic chiral effective field theory at leading order. Among the 15 relevant low energy constants, eight of them are determined by fitting to the state of the art lattice QCD data of the HAL QCD Collaboration (with $m_{π} = 146$ MeV), and the rest are either taken from the study of the $S = - 1$ hyperon-nucleon systems, assuming strict SU(3) flavor symmetry, or temporarily set equal to zero. Using the so-obtained low energy constants, we extrapolate the results to the physical point, and show that they are consistent with the available experimental scattering data. Furthermore, we demonstrate that the $ΛΛ$ and $Ξ N$ phase shifts near the $Ξ N$ threshold are very sensitive to the lattice QCD data fitted, to the pion mass, and to isospin symmetry breaking effects. As a result, any conclusion drawn from lattice QCD data at unphysical pion masses (even close to the physical point) should be taken with caution. Our results at the physical point, similar to the lattice QCD data, show that a resonance/quasi-bound state may appear in the $I = 0$ $ΛΛ$ / $Ξ N$ channel.
Comments:
20 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1809.03199 [pdf]
PRC(2018)·46 citations
07
[Submitted on 10 Sept 2018]
On the contribution of the P and D partial-wave states to the binding energy of the triton in the Bethe-Salpeter-Faddeev approach
S. G. Bondarenko · V. V. Burov · S. A. Yurev
The influence of the partial-wave states with nonzero orbital moment of the nucleon pair on the binding energy of the triton in the relativistic case is considered. The relativistic generalization of the Faddeev equation in the Bethe-Salpeter formalism is applied. Two-nucleon t matrix is obtained from the Bethe-Salpeter equation with separable kernel of nucleon-nucleon interaction of the rank one. The kernel form factors are the relativistic type of the Yamaguchi functions. The following two-nucleon partial-wave states are considered: $^{1} S_{0}$ , $^{3} S_{1}$ , $^{3} D_{1}$ , $^{3} P_{0}$ , $^{1} P_{1}$ , $^{3} P_{1}$ . The system of the integral equations are solved by using the iteration method. The binding energy of the triton and three-nucleon amplitudes are found. The contribution of the P and D states to the binding energy of triton is given.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1809.03271 [pdf]
Phys.Atom.Nucl.(2019)·3 citations
08
[Submitted on 10 Sept 2018]
Symmetry energy in neutron star matter
Claudio O. Dorso · Guillermo A. Frank · Jorge A. Lopez
We investigate the structure attained by neutron star matter with proton to neutron ratios ranging from x=0.1 to 0.5, densities in the range of 0.02 fm-3 to 0.085 fm-3, and temperatures T<4 MeV. In particular we study the pasta shapes and the phase changes previously observed in nuclear matter, as well as the behavior of the symmetry energy. We corroborate the existence of homogeneous to non-homogeneous phase transitions, and the different values of the symmetry energy at different densities and temperatures.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1809.03370 [pdf]
NPA(2019)·9 citations
09
[Submitted on 10 Sept 2018]
Influence of the interactions of scalar mesons on the behavior of the symmetry energy
Noemi Zabari🇵🇱 · Sebastian Kubis🇵🇱 · Włodzimierz Wójcik🇵🇱
Symmetry energy behavior of scalar mesons interactions is analyzed within the framework of the standard relativistic mean field model. Whereas the presence of the $δ$ meson itself makes the symmetry energy stiffer, the crossing term $δ - σ$ allows its slope to decrease to the suggested experimental value. Moreover, such controlling of the symmetry energy does not significantly affect the stiffness of the equation of state and acceptable neutron star masses result. Interestingly, for the most plausible value of the symmetry energy slope, the phase transition occurs in the neutron star core.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1809.03420 [pdf]
PRC(2019)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE