Nuclear Theory·nucl-th

Monday·March 2, 2020

10 papers—5 primary·5 cross-listed

01
[Submitted on 27 Feb 2020]
$β$ decay of even-A nuclei within the interacting boson model based on nuclear density functional theory
K. Nomura🇭🇷 · R. Rodríguez-Guzmán🇰🇼 · L. M. Robledo🇪🇸
We compute the $β$ -decay $f t$ -values within the frameworks of the energy density functional (EDF) and the interacting boson model (IBM). Based on the constrained mean-field calculation with the Gogny-D1M EDF, the IBM Hamiltonian for an even-even nucleus and essential ingredients of the interacting boson-fermion-fermion model (IBFFM) for describing the neighboring odd-odd nucleus are determined in a microscopic way. Only the boson-fermion and residual neutron-proton interaction strengths are determined empirically. The Gamow-Teller (GT) and Fermi (F) transition rates needed to compute the $β$ -decay $f t$ -values are obtained without any additional parameter or quenching of the $g_{A}$ factor. The observed $\ft$ values for the $β^{+}$ decays of the even-even Ba into odd-odd Cs nuclei, and of the odd-odd Cs to the even-even Xe nuclei, with mass $A \approx 130$ are reasonably well described. The predicted GT and F transition rates represent a sensitive test of the quality of the IBM and IBFFM wave functions.
Comments:
10 pages, 2 figures, 4 tables. arXiv admin note: text overlap with arXiv:1912.01846
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2002.12357 [pdf]
PRC(2020)·19 citations
02
[Submitted on 27 Feb 2020]
Neutral baryonic systems with strangeness
H. Garcilazo🇲🇽 · A. Valcarce🇪🇸 · J. Vijande🇪🇸
We review the status as regards the existence of three- and four-body bound states made of neutrons and $Λ$ hyperons. For interesting cases, the coupling to neutral baryonic systems made of charged particles of different strangeness has been addressed. There are strong arguments showing that the $Λ nn$ system has no bound states. $ΛΛ nn$ strong stable states are not favored by our current knowledge of the strangeness $- 1$ and $- 2$ baryon-baryon interactions. However, a possible $Ξ^{-} t$ quasibound state decaying to $ΛΛ nn$ might exist in nature. Similarly, there is a broad agreement about the nonexistence of $ΛΛ n$ bound states. However, the coupling to $Ξ N N$ states opens the door to a resonance above the $ΛΛ n$ threshold.
Comments:
Invited Review. 22 pages. arXiv admin note: text overlap with arXiv:1911.07194"
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2002.12365 [pdf]
IJMPE(2020)·1 citation
03
[Submitted on 27 Feb 2020]
Dalitz plots and lineshape of $a_{1} (1260)$ from a relativistic three-body unitary approach
Daniel Sadasivan🇺🇸 · Maxim Mai🇺🇸 · Hakan Akdag🇩🇪 · Michael Döring🇺🇸
We formulate the final state interaction of the $a_{1} (1260)$ resonance decay in a manifestly three-body unitary parameterization and fit it to the $a_{1} (1260)$ lineshape measured by the ALEPH experiment. Dalitz plots calculated from this fit are presented. The work demonstrates the feasibility to numerically solve a previously derived amplitude and its generalization to isobars with spin and coupled channels. The model can also be applied to other meson decays and modified for the finite-volume problem as it arises in lattice QCD due to its manifest unitarity.
Comments:
14 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2002.12431 [pdf]
PRD(2020)·36 citations
04
[Submitted on 28 Feb 2020]
System response to the initial energy-momentum tensor in relativistic heavy-ion collisions
Jefferson Sousa🇧🇷 · Jorge Noronha🇺🇸 · Matthew Luzum🇧🇷
The evolution of a relativistic heavy-ion collision is typically understood as a process that transmutes the initial geometry of the system into the final momentum distribution of observed hadrons, which can be described via a cumulant expansion of the initial distribution of energy density and is represented at leading order as the well-known eccentricity scaling of anisotropic flow. We summarize a proposed extension of this framework to include the contribution from initial momentum-space properties, as encoded in other components of the energy-momentum tensor. Numerical tests validate this proposal.
Comments:
Proceedings for Quark Matter 2019
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2002.12735 [pdf]
NPA(2021)·4 citations
05
[Submitted on 28 Feb 2020]
Effects of high- $j$ orbitals, pairing and deformed neutron shells on upbendings of ground-state bands in neutron-rich even-even isotopes $^{170 - 184}$ Hf
Xiao-Tao He · Yang Cao · Xiao-Ling Gan
The ground-state bands (GSBs) in the even-even hafnium isotopes $^{170 - 184}$ Hf are investigated by using the cranked shell model (CSM) with pairing correlations treated by the particle-number conserving (PNC) method. The experimental kinematic moments of inertia are reproduced very well by theoretical calculations. The second upbending of the GSB at high frequency $ℏ ω \approx 0.5$ MeV observed (predicted) in $^{172}$ Hf ( $^{170, 174 - 178}$ Hf) attributes to the sudden alignments of the proton high- $j$ orbitals $π 1 i_{13/2}$ $(1/ 2^{+} [660])$ , $π 1 h_{9/2}$ $(1/ 2^{-} [541])$ and orbital $π 1 h_{11/2}$ $(7/ 2^{-} [523])$ . The first upbendings of GSBs at low frequency $ℏ ω = 0.2 - 0.3$ MeV in $^{170 - 178}$ Hf, which locate below the deformed neutron shell $N = 108$ , attribute to the alignment of the neutron orbital $ν 1 i_{13/2}$ . For the heavier even-even isotopes $^{180 - 184}$ Hf, compared to the lighter isotopes, the first band-crossing is delayed to the high frequency due to the existence of the deformed shells $N = 108, 116$ . The upbendings of GSBs in $^{180 - 184}$ Hf are predicted to occur at $ℏ ω \approx 0.5$ MeV, which come from the sharp raise of the simultaneous alignments of both proton $π 1 i_{13/2}$ , $π 1 h_{9/2}$ and neutron $ν 2 g_{9/2}$ orbitals. The pairing correlation plays a very important role in the rotational properties of GSBs in even-even isotopes $^{180 - 184}$ Hf. Its effects on upbendings and band-crossing frequencies are investigated.
Comments:
14pages,12figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2002.12807 [pdf]
PRC(2020)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

β decay of even-A nuclei within the interacting boson model based on nuclear density functional theory

Neutral baryonic systems with strangeness

Dalitz plots and lineshape of a1​(1260) from a relativistic three-body unitary approach

System response to the initial energy-momentum tensor in relativistic heavy-ion collisions

Effects of high-j orbitals, pairing and deformed neutron shells on upbendings of ground-state bands in neutron-rich even-even isotopes 170−184Hf

Affiliations

$β$ decay of even-A nuclei within the interacting boson model based on nuclear density functional theory

Dalitz plots and lineshape of $a_{1} (1260)$ from a relativistic three-body unitary approach

Effects of high- $j$ orbitals, pairing and deformed neutron shells on upbendings of ground-state bands in neutron-rich even-even isotopes $^{170 - 184}$ Hf