Nuclear Theory·nucl-th

Friday·July 29, 2022

11 papers—8 primary·3 cross-listed

01
[Submitted on 27 Jul 2022]
Clustering in nuclei at finite temperature
Esra Yüksel🇹🇷 · Florian Mercier🇫🇷 · Jean-Paul Ebran🇫🇷 · Elias Khan🇫🇷
We investigate the localization and clustering features in $^{20}$ Ne ( $N = Z$ ) and neutron-rich $^{32}$ Ne nuclei at zero and finite temperatures. The finite temperature Hartree-Bogoliubov theory is used with the relativistic density-dependent meson-nucleon coupling functional DD-ME2. It is shown that clustering features gradually weaken with increasing temperature and disappear when the shape phase transition occurs. Considering thermal fluctuations in the density profiles, the clustering features vanish at lower temperatures, compared to the case without thermal fluctuations. The effect of the pairing correlations on the nucleon localization and the formation of cluster structures are also studied at finite temperatures. Due to the inclusion of pairing in the calculations, cluster structures are preserved until the critical temperatures for the shape phase transition are reached. Above the critical temperature of the shape phase transition, the clustering features suddenly disappear, which differs from the results without pairing.
Comments:
11 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.13764 [pdf]
PRC(2022)·12 citations
02
[Submitted on 27 Jul 2022]
Coulomb Form Factors of $^{27}$ Al and $^{31}$ P Nuclei Using Coulomb valance Tassie model and Bohr-Mottelson Collective Models with Different Potentials
Khalid S. Jassim · Ranya Mahmoud Mohammed
The longitudinal Coulomb C0, C2 and C4 form factors with core-polarization effects have been studied using shell model calculations for 3/2 $_{1}^{+}$ state with excitation energy of 1.069 MeV, 5/2 $_{2}^{+}$ state with excitation energy of 2.706 MeV and 7/2 $_{1}^{+}$ state with excitation energy of 2.304 MeV state in $^{27}$ Al nucleus and 1/2 state in $^{31}$ P nucleus. The two-body effective interaction Wildenthal and universal sd-shell interaction A (USDA) are used for sd-shell orbits. The Coulomb valance Tassie model (CVTM) and Bohr-Mottelson (BM) collective model have been used to calculated the Core-polarization effects. Three potentials are Harmonic Oscillator (HO) potential, Wood-Saxon (WS) and SKX potential,which have been used to calculated the wave functions of radial single particle matrix elements. The results for these potentials are compared with final update experimental data. The calculations with inclusions of core-polarization effects give a good agreements of experimental data.
Comments:
5 page, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.13804 [pdf]
0 citations
03
[Submitted on 28 Jul 2022]
Resonance-to-bound transition of $^{5}$ He in neutron matter and its analogy with heteronuclear Feshbach molecule
Hiroyuki Tajima🇯🇵 · Hajime Moriya🇯🇵 · Wataru Horiuchi🇯🇵 · Kei Iida🇯🇵 · Eiji Nakano🇯🇵
We theoretically investigate the fate of a neutron-alpha $p$ -wave resonance in dilute neutron matter, which may be encountered in neutron stars and supernova explosions. While $^{5}$ He is known as a resonant state that decays to a neutron and an alpha particle in vacuum, this unstable state turns into a stable bound state in the neutron Fermi sea because the decay process is forbidden by the Pauli-blocking effect of neutrons. Such a resonance-to-bound transition assisted by the Pauli-blocking effect can be realized in cold atomic experiments for a quantum mixture near the heteronuclear Feshbach resonance.
Comments:
7 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas)
arXiv:
2207.13907 [pdf]
PRC(2022)·5 citations
04
[Submitted on 28 Jul 2022]
Non-equilibrium components in very low transverse momentum region in high-energy nuclear collisions
Yuuka Kanakubo🇯🇵 · Yasuki Tachibana🇯🇵 · Tetsufumi Hirano🇯🇵
We analyze Pb+Pb collisions at $s_{NN} = 2.76$ TeV with a novel framework based on the dynamical core--corona picture that describes particle productions from both equilibrium and non-equilibrium components. We remark the possibility of the contribution from non-equilibrium components at very low transverse momentum ( $p_{T}$ ) region and show that such contributions significantly affect $p_{T}$ -integrated four-particle cumulants. These results strongly suggest the necessity of non-equilibrium components when one extracts properties of the quark-gluon plasma from experimental data using sophisticated dynamical models based on relativistic hydrodynamics.
Comments:
7 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2207.13966 [pdf]
PRC(2022)·14 citations
05
[Submitted on 28 Jul 2022]
Kinetic theory for massive spin-1 particles
David Wagner🇩🇪 · Nora Weickgenannt🇩🇪 · Enrico Speranza🇺🇸
We calculate the Wigner function for charged spin-1 particles in inhomogeneous classical electromagnetic fields, going to first order in a power series in $ℏ$ . The Boltzmann equation for the scalar distribution function obtained from this formalism agrees with previous calculations for spin-1/2 particles. In particular, we recover a Mathisson force of twice the magnitude, correctly reflecting the higher dipole moment of vector mesons. Evolution equations for vector and tensor degrees of freedom are obtained, and global equilibrium is discussed.
Comments:
Contribution to the proceedings of Quark Matter 2022. 6 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2207.14060 [pdf]
Acta Phys.Polon.Supp.(2023)·2 citations
06
[Submitted on 28 Jul 2022]
New developments in relativistic hydrodynamics
Nora Weickgenannt🇩🇪
We review recent progress in relativistic hydrodynamics, discussing causal and stable first-order hydrodynamics, known as BDNK theories, hydrodynamic attractors, as well as hydrodynamics near the chiral critical point and spin hydrodynamics.
Comments:
Contribution to Quark Matter 2022, 8 pages
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.14095 [pdf]
Acta Phys.Polon.Supp.(2023)·1 citation
07
[Submitted on 28 Jul 2022]
Inner crust equations of state for CompOSE
Tuhin Malik · Helena Pais
In this paper, we present some relativistic mean-field inner crust equations of state that have recently been uploaded in the CompOSE online repository. These equations of state fulfill experimental and microscopic constraints, and are also able to reproduce two solar-mass stars. We integrate the TOV equations to obtain the mass-radius relation, and we also calculate the tidal deformability, compactness, and effective tidal deformability to compare with the latest astrophysical data from NICER and LIGO and Virgo.
Comments:
13 pages, 5 figures, 3 tables, accepted for publication in the EPJA's Topical Issue "CompOSE: a repository for Neutron Star Equations of State and Transport Properties"
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2207.14153 [pdf]
EPJA(2022)·1 citation
08
[Submitted on 28 Jul 2022]
Final-state interactions and spin structure in $E 1$ breakup of $^{1} 1$ Li in Halo EFT
Matthias Göbel🇩🇪 · Bijaya Acharya🇺🇸 · Hans-Werner Hammer🇩🇪 · Daniel R. Phillips🇺🇸
We calculate the $E 1$ breakup of the $2 n$ halo nucleus $^{11}$ Li in Halo Effective Field Theory (Halo EFT) at leading order. In Halo EFT, $^{11}$ Li is treated as a three-body system of a $^{9}$ Li core and two neutrons. We present a detailed investigation of final-state interactions (FSI) in the neutron-neutron $(nn)$ and neutron-core $(n c)$ channels. We employ Moller operators to formulate an expansion scheme that satisfies the non-energy-weighted cluster sum rule and successively includes higher-order terms in the multiple-scattering series for the FSI. Computing the $E 1$ strength up to third order in this scheme, we observe apparent convergence and good agreement with experiment. The neutron-neutron FSI is by far the most important contribution and largely determines the maximum value of the $E 1$ distribution. However, inclusion of $n c$ FSI does shift the peak position to slightly lower energies. Moreover, we investigate the sensitivity of the $E 1$ response to the spin structure of the neutron- $^{9}$ Li interaction. We contrast results for an interaction that is the same in the spin-1 and spin-2 channels with one that is only operative in the spin-2 channel, and find that good agreement with experimental data is only obtained if the interaction is present in both spin channels. The latter case is shown to be equivalent to a calculation in which the spin of $^{9}$ Li is neglected.
Comments:
23 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2207.14281 [pdf]
PRC(2023)·7 citations
09
[Submitted on 27 Jul 2022] (cross-list from hep-ph)
Contact interaction analysis of octet baryon axialvector and pseudoscalar form factors
Peng Cheng🇨🇳 · Fernando E. Serna🇨🇴 · Zhao-Qian Yao🇨🇳 · Chen Chen🇨🇳 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇨🇳
Octet baryon axial, induced pseudoscalar, and pseudoscalar form factors are computed using a symmetry-preserving treatment of a vector $\times$ vector contact interaction (SCI), thereby unifying them with an array of other baryon properties and analogous treatments of semileptonic decays of pseudoscalar mesons. The baryons are treated as quark--plus--interacting-diquark bound states, whose structure is obtained by solving a Poincaré-covariant Faddeev equation. The approach is marked by algebraic simplicity, involves no free parameters, and since it is symmetry preserving, all consequences of partial conservation of the axial current are manifest. It is found that SCI results are consistent with only small violations of SU $(3)$ -flavour symmetry, an outcome which may be understood as a dynamical consequence of emergent hadron mass. The spin-flavour structure of the Poincaré-covariant baryon wave functions is expressed in the presence of both flavour-antitriplet scalar diquarks and flavour-sextet axialvector diquarks and plays a key role in determining all form factors. Considering neutral axial currents, SCI predictions for the flavour separation of octet baryon axial charges and, therefrom, values for the associated SU $(3)$ singlet, triplet, and octet axial charges are obtained. The results indicate that at the hadron scale, $ζ_{H}$ , valence degrees-of-freedom carry roughly 50% of an octet baryon's total spin. Since there are no other degrees-of-freedom at $ζ_{H}$ , the remainder may be associated with quark+diquark orbital angular momentum.
Comments:
20 pages, 6 figures, 15 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2207.13811 [pdf]
PRD(2022)·26 citations
10
[Submitted on 28 Jul 2022] (cross-list from hep-ph)
Possible $Λ_{c} Λ ˉ_{c}$ molecular states and their productions in nulceon-antinulceon collision
Lin-Qing Song🇨🇳 · Dan Song🇨🇳 · Jun-Tao Zhu🇨🇳 · Jun He🇨🇳
In this work, a study of possible molecular states from the $Λ_{c} Λ ˉ_{c}$ interaction and their productions in nucleon-antinucleon collision is performed in a quasipotential Bethe-Salpeter equation approach. Two bound states with quantum numbers $J^{P C} = 0^{-+}$ and $1^{--}$ are produced with almost the same binding energy from the $Λ_{c} Λ ˉ_{c}$ interaction which is described by the light meson exchanges. However, the result does not support the assignment of experimentally observed $Y (4630)$ as a $Λ_{c} Λ ˉ_{c}$ molecular state because it is hard to obtain a peak near experimental mass of the $Y (4630)$ which is far above the $Λ_{c} Λ ˉ_{c}$ threshold. The possibility to search these states in nucleon-antinucleon collision is studied by including couplings to $N N ˉ$ and $D^{(*)} D ˉ^{(*)}$ channels. The peaks can be found obviously near the $Λ_{c} Λ ˉ_{c}$ threshold in the $D^{*} D ˉ^{*}$ channel at an order of amplitude of 10 $μ$ b. Too small width of state with $0^{-+}$ may lead to the difficulty to be observed in experiment. Based on the results in the current work, search for the $Λ_{c} Λ ˉ_{c}$ molecular state with $1^{--}$ is suggested in process $N N ˉ \to D^{*} D ˉ^{*}$ , which is accessible at $P ˉ ANDA$ .
Comments:
4 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2207.13957 [pdf]
PLB(2022)·15 citations
11
[Submitted on 28 Jul 2022] (cross-list from hep-ph)
Sensitivity of the $η^{(')} \to π^{0} γ γ$ and $η^{'} \to η γ γ$ decays to a sub-GeV leptophobic $U (1)_{B}$ boson
Rafel Escribano🇪🇸 · Sergi Gonzàlez-Solís🇺🇸 · Emilio Royo🇪🇸
The sensitivity of the rare decays $η^{(')} \to π^{0} γ γ$ and $η^{'} \to η γ γ$ to signatures of a leptophobic $B$ boson in the MeV-GeV mass range is analyzed in this work. By adding an explicit $B$ -boson resonance exchange, $η \to B γ \to π^{0} γ γ$ , to the Standard Model contributions from vector and scalar meson exchanges, and employing experimental data for the associated branching ratios, it allows us to improve the current constraints on the $B$ -boson mass $m_{B}$ and coupling to Standard Model particles $α_{B}$ . From these constraints and the analysis of the available experimental $γ γ$ invariant mass distribution, we show that a $B$ -boson signature in the resonant mass range $m_{π^{0}} ≲ m_{B} ≲ m_{η}$ is strongly suppressed and would be very difficult to experimentally identify, assuming that the leptophobic $B$ boson only decays to Standard Model particles. In contrast, the limits outside this mass window are less stringent and the corresponding $t$ - and $u$ -channel signatures may still be observable in the data, as it occurs with the nonresonant Standard Model $ρ$ , $ω$ and $ϕ$ meson exchanges. In addition, we make use of experimental data from the $η^{'} \to π^{0} γ γ$ and $η^{'} \to η γ γ$ decays to explore larger $B$ -boson masses. Our results are relevant for the $B$ -boson search programs at existing and forthcoming light-meson facilities, such as KLOE(-II) and Jefferson Lab Eta Factory experiments.
Comments:
15 pages, 12 figures, 1 table; v2 includes a discussion of the uncertainty of the Standard Model estimate and an improvement in the overall presentation
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2207.14263 [pdf]
PRD(2022)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE