Nuclear Theory·nucl-th

Wednesday·August 4, 2021

9 papers—5 primary·4 cross-listed

01
[Submitted on 3 Aug 2021]
Spin-polarized phases of $^{3} P_{2}$ superfluids in neutron stars
Takeshi Mizushima · Shigehiro Yasui · Daisuke Inotani · Muneto Nitta
The interior of a neutron star is expected to be occupied by a neutron $^{3} P_{2}$ superfluid, which is the condensate of spin-triplet $p$ -wave Cooper pairs of neutrons with total angular momentum $J = 2$ . Here we investigate the thermodynamic stability of $^{3} P_{2}$ superfluids in a neutron-star interior under a strong magnetic field. Using the theory incorporating the finite size correction of neutron Fermi surface, we show that the spin-polarized phases of $^{3} P_{2}$ superfluids, the magnetized biaxial nematic phase and the ferromagnetic phase, appear in high temperatures and high magnetic fields. These phases were missed in the previous studies using the quasiclassical approximation in which dispersions of neutrons are linearized around the Fermi surface. In particular, the ferromagnetic phase, which is the condensation of Cooper-paired neutrons with fully polarized spins, appears between the normal phase and the biaxial nematic phase and enlarge the thermodynamic stability of $^{3} P_{2}$ superfluids under strong magnetic fields. Furthermore, we present the augmented Ginzburg-Landau theory that incorporates the thermodynamic stability of spin-polarized $^{3} P_{2}$ superfluid phases.
Comments:
14 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Superconductivity (cond-mat.supr-con)
arXiv:
2108.01256 [pdf]
PRC(2021)·12 citations
02
[Submitted on 3 Aug 2021]
Collective states of even-even nuclei in gamma-rigid quadrupole Hamiltonian with Minimal Length under the sextic potential
A. El Batoul · M. Oulne · I.Tagdamte
In the present paper, we study the collective states of even even nuclei in gamma rigid mode within the sextic potential and the Minimal Length (ML) formalism in Bohr Mottelson model. The eigenvalues problem for this latter is solved by means conjointly of Quasi-Exact Solvability (QES) and a Quantum Perturbation Method (QPM). Numerical calculations are performed for 35 nuclei:(98 108)Ru, (100 102)Mo, (116 130)Xe, (180 196)Pt, (172)Os, (146 150)Nd, (132 134)Ce, (154)Gd, (156)Dy and (150 152)Sm. Through this study, it appears that our elaborated model leads to an improved agreement of the theoretical results with the corresponding experimental data by reducing the rms with a rate going up to 63% for some nuclei. This comes out from the fact that we have combined the sextic potential, which is a very useful phenomenological potential, with the formalism of the ML which is based on the generalized uncertainty principle and which is in turn a quantum concept widely used in quantum physics. Besides, we investigate the effect of ML on energy ratios, transition rates, moments of inertia and a shape phase transition for the most numerous isotopic chains, namely Ru, Xe, Nd and Pt.
Comments:
arXiv admin note: text overlap with arXiv:1508.00728 by other authors
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.01463 [pdf]
J.Phys.G(2021)·5 citations
03
[Submitted on 3 Aug 2021]
Pion photoproduction in chiral perturbation theory with explicit treatment of the $Δ (1232)$ resonance
N. Rijneveen🇩🇪 · A. M. Gasparyan🇩🇪 · H. Krebs🇩🇪 · E. Epelbaum🇩🇪
We study the reaction of pion photoproduction on the nucleon in the framework of chiral perturbation theory with explicit $Δ (1232)$ degrees of freedom. In the covariant approach, we give results up to order $ϵ^{3}$ in the small scale expansion scheme. Furthermore, we provide $Δ$ -less and $Δ$ -full results obtained in the heavy-baryon scheme to analyze the differences to the covariant approach. Low energy constants are fitted to multipole amplitudes using theoretical truncation errors estimated by a Bayesian approach. We also compare our findings to data of neutral pion production cross sections and polarization asymmetries. The description of the reaction is clearly improved by the explicit treatment of the $Δ (1232)$ resonance.
Comments:
35 pages, 13 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2108.01619 [pdf]
PRC(2022)·12 citations
04
[Submitted on 3 Aug 2021]
Antiproton-deuteron hydrogenic states in optical models
Rimantas Lazauskas · Jaume Carbonell
By solving the Faddeev equations for the p̄pn system, we compute the antiproton-deuteron level shifts and widths for the lowest hydrogenic states as well as the corresponding p̄d scattering lengths and volumes. The p̄d annihilation densities are obtained and compared to the nuclear density of deuterium. The validity of the Trueman relation for composite particles is studied. The strong part of N̄N interaction is described by two different optical models, including the p̄p-n̄n coupling and n-p mass difference, while for NN several realistic interactions are used.
Comments:
To appear in Physics Letters B (2021)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2108.01630 [pdf]
PLB(2021)·14 citations
05
[Submitted on 3 Aug 2021]
Structural properties of nuclei with semi-magic number N(Z)=40
R. Sharma · A. Jain · M. Kaushik · S. K. Jain · G. Saxena
Various ground state properties are explored for full isotonic(isotopic) chain of neutron number N(proton number Z) $=$ 40 using different families of Relativistic Mean-Field theory. Several properties such as nucleon separation energies, pairing energies, deformation, radii and nucleon density distributions are evaluated and compared with the experimental data as well as those from other microscopic and macroscopic models. N $=$ 40 isotonic chain presents ample of support for the neutron magicity and articulates double magicity in recently discovered $^{60}$ Ca and $^{68}$ Ni. Our results are in close conformity with recently measured value of charge radius of $^{68}$ Ni [S. Kaufmann \textit{et al.}, Phys. Rev. Lett. 124, 132502 (2020)] which supports the N $=$ 40 magicity. Contrarily, Zr isotopes (Z $=$ 40) display variety of shapes leading to the phenomenon of shape transitions and shape co-existence. The role of 3s $_{1/2}$ state, which leads to central depletion if unoccupied, is also investigated. $_{16}^{56}$ S and $_{40}^{122}$ Zr are found to be doubly bubble nuclei.
Comments:
Accepted in Int. J. Mod. Phys. E. arXiv admin note: text overlap with arXiv:1705.03315 by other authors
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.01631 [pdf]
IJMPE(2021)·4 citations
06
[Submitted on 3 Aug 2021] (cross-list from quant-ph)
Exposing minimal composition of Kohn-Sham theory and its extendability
H. Nakada
Reducing the many-fermion problem to a set of single-particle (s.p.) equations, the Kohn-Sham (KS) theory has provided a practical tool to implement \textit{ab initio} calculations of ground-state energies and densities in many-electron systems. There have been attempts to extend the KS theory so that it could describe other physical quantities, or it could be applied to other many-fermion systems. By generalizing and reformulating the KS theory in terms of the 1-body density matrix, we expose the minimal composition of the theory that enables the reduction of the many-fermion problem to the s.p. equations. Based on the reformulation, several basic issues are reconsidered. The $v$ - and $N$ -representabilities for the KS theory are distinguished from those for the Hohenberg-Kohn theorem. Criteria for the extendability of the KS theory are addressed.
Comments:
33 pages including 2 figures; to appear in Phys. Scr. (Several typos have been corrected from the previous version.)
Subjects:
Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
arXiv:
2108.01232 [pdf]
Phys.Scripta(2023)·4 citations
07
[Submitted on 3 Aug 2021] (cross-list from hep-ph)
Transverse-momentum-dependent parton distribution functions for spin-1 hadrons
S. Kumano🇯🇵 · Qin-Tao Song🇨🇳
We show transverse-momentum-dependent parton distribution functions (TMDs) for spin-1 hadrons including twist-3 and 4 functions by taking the decomposition of a quark correlation function in the Lorentz-invariant way with the conditions of Hermiticity and parity invariance. We found 30 new TMDs in the tensor-polarized spin-1 hadron at twists 3 and 4 in addition to 10 TMDs at twist 2. Since time-reversal-odd terms of the collinear correlation function should vanish after integrals over the partonic transverse momentum, we obtained new sum rules for the time-reversal-odd structure functions, $\int d^{2} k_{T} g_{LT} = \int d^{2} k_{T} h_{LL} = \int d^{2} k_{T} h_{3 LL}$ $= 0$ , at twists 3 and 4. We also indicated that transverse-momentum-dependent fragmentation functions exist in tensor-polarized spin-1 hadrons. The TMDs can probe color degrees of freedom, so that they are valuable in providing unique opportunities for creating interdisciplinary physics fields such as gluon condensate, color Aharonov-Bohm effect, and color entanglement. We also found three new collinear PDFs at twists 3 and 4, and a twist-2 relation and a sum rule were derived in analogy to the Wandzura-Wilczek relation and the Burkhardt-Cottingham sum rule on the structure function $g_{2}$ .
Comments:
SciPost Physics Proceedings, 28th International workshop on Deep-Inelastic Scattering and Related Subjects (DIS2021), (Online) Stony Brook, New York, USA, April 12-16, 2021
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2108.01381 [pdf]
SciPost Phys.Proc.(2022)·0 citations
08
[Submitted on 3 Aug 2021] (cross-list from nucl-ex)
Impact of $^{7}$ Be breakup on $^{7}$ Li(p,n) Neutron Spectrum
Midhun C.V · M.M Musthafa · S.V Suryanarayana · T. Santhosh · A. Baishya · P. Patil · A Pal · P.C Rout · S Santra · R. Kujur · Antony Joseph · Shaima A and 8 other authors
The formation of continuum neutron distribution in $^{7}$ Li(p,n) has been identified as due to the coupling of the $^{7}$ Be breakup levels to the final state of the reaction. The continuum neutron spectra produced by $^{7}$ Li(p,n) reaction has been estimated by measuring the double differential cross sections for continuum and resonant breakup of $^{7}$ Be, through $^{7}$ Li(p,n) $^{7}$ Be $^{*}$ reaction at 21 MeV of proton energy. The breakup contributions from continuum and $5/ 2^{-}$ , $7/ 2^{-}$ states of $^{7}$ Be have been identified. The measured double differential cross sections have been reproduced through CDCC-CRC calculations. The cross sections were projected to neutron spectrum using Monte-Carlo approach and validated using experimentally measured $^{3}$ He gated neutron spectra. $^{7}$ Li(p,n) neutron spectrum at 20 MeV incident proton energy measured by McNaughton. et al. has been reproduced by adapting estimated model parameters for the reaction.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.01382 [pdf]
PRC(2021)·10 citations
09
[Submitted on 3 Aug 2021] (cross-list from hep-ph)
Nonlinear diffusion of gluons
Georg Wolschin🇩🇪
It is proposed to consider the fast thermalization of gluons in relativistic heavy-ion collisions as a diffusion process in momentum space. Closed-form analytical solutions of a nonlinear boson diffusion equation (NBDE) with constant drift and diffusion coefficients v, D and boundary conditions at the singularity are derived. The time evolution towards local central temperatures T< 600 MeV through inelastic gluon scatterings in heavy-ion collisions is calculated for under- and overoccupied systems in the full momentum range. The results are consistent with QCD-based numerical calculations for gluon thermalization via inelastic gluon collisions.
Comments:
14 pages, 6 figures; as published in PHYSICA A
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2108.01607 [pdf]
Physica A: Statistical Mechanics and its Applications(2022)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE