Nuclear Theory·nucl-th

Monday·May 11, 2020

8 papers—5 primary·3 cross-listed

01
[Submitted on 8 May 2020]
Predictions of $α$ decay half-lives for even-even superheavy nuclei with $104 ⩽ Z ⩽ 128$ based on two-potential approach within cluster-formation model
H. M. Liu · J. Y. Xu · J. G. Deng · B. He · X. H. Li
In present work, we systematically study the $α$ decay half-lives of 170 even-even nuclei with $60 ⩽ Z ⩽ 118$ within the two-potential approach while the $α$ decay preformation factor $P_{α}$ is obtained by the cluster-formation model. The calculated results can well reproduce the experimental data. In addition, we extend this model to predict the $α$ decay half-lives of 64 even-even nuclei with $104 ⩽ Z ⩽ 128$ whose $α$ decay is energetically allowed or observed but not yet quantified. For comparing, the two famous models i.e. SemFIS proposed by D. Poenaru $e t a l .$ [\href {https://doi.org/10.1209/0295-5075/77/62001}{Europhys. Lett. \textbf{77} (2007) 62001}] and UDL proposed by C. Qi $e t a l .$ [\href {https://doi.org/10.1103/PhysRevLett.103.072501}{Phys. Rev. Lett. \textbf{103} (2009) 072501}] are used. The predicted results of these models are basically consistent. At the same time, through analyzing the changing trend of $α$ decay energy $Q_{α}$ of \emph{Z} = 118, 120, 122, 124, 126 and 128 isotopes nuclei with the increasing of neutron number \emph{N} and that of $α$ decay preformation factor $P_{α}$ of those isotopes even-even nuclei with the increasing of neutron number \emph{N}, \emph{N} = 178 may be a new neutron magic number.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.03831 [pdf]
IJMPE(2020)·14 citations
02
[Submitted on 8 May 2020]
Systematic study of the $α$ decay preformation factor of nuclei around the $Z = 82$ , $N = 126$ shell closures within a generalized liquid drop model
Hong-Ming Liu · You-Tian Zou · Xiao-Pan · Xiao-Jun Bao · Xiao-Hua Li
In this work, we systematically study the $α$ decay preformation factors $P_{α}$ and $α$ decay half-lives of 152 nuclei around $Z$ = 82, $N$ = 126 closed shells based on a generalized liquid drop model while $P_{α}$ is extracted from the ratio of the calculated $α$ decay half-life to the experimental one. The results show that there is an obvious linear relationship between $P_{α}$ and the product of valance protons (holes) $N_{p}$ and valance neutrons (holes) $N_{n}$ . At the same time, we extract the $ $P_{α}$ values of even-even nuclei around $Z$ = 82, $N$ = 126 closed shells from the work of Sun \textit{et al.} [\href {https://doi.org/10.1088/1361-6471/aac981} {J. Phys. G: Nucl. Part. Phys. $45$ , 075106 (2018)}], in which the $P_{α}$ can be calculated by two different microscopic formulas. We find that the $P_{α}$ are also related to $N_{p} N_{n}$ . Combining with our previous works [Sun \textit{et al.}, \href {https://doi.org/10.1103/PhysRevC.94.024338} {Phys. Rev. C $94$ , 024338 (2016)}; Deng \textit{et al.}, \href {https://doi.org/10.1103/ PhysRevC 96.024318} {ibid. $96$ , 024318 (2017)}; Deng \textit{et al.}, \href {https://doi.org/10.1103/PhysRevC.97.044322} {ibid. $97$ , 044322 (2018)}] and the work of Seif \textit{et al.} [\href {http://dx.doi.org/10.1103/PhysRevC.84.064608}{Phys. Rev. C $84$ , 064608 (2011)}], we suspect that this phenomenon of linear relationship for the nuclei around those closed shells is model independent. It may be caused by the effect of the valence protons (holes) and valence neutrons (holes) around the shell closures. Finally, using the formula obtained by fitting the $P_{α}$ calculated by the generalized liquid drop model (GLDM), we calculate the $α$ decay half-lives of these nuclei. The calculated results are agree with the experimental data well.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.03836 [pdf]
CPC(2020)·21 citations
03
[Submitted on 8 May 2020]
Static quadrupole moments of nuclear chiral doublet bands
Q. B. Chen🇩🇪 · N. Kaiser🇩🇪 · Ulf-G. Meißner🇩🇪 · J. Meng🇨🇳
The static quadrupole moments (SQMs) of nuclear chiral doublet bands are investigated for the first time taking the particle-hole configuration $π (1 h_{11/2}) \otimes ν (1 h_{11/2})^{- 1}$ with triaxial deformation parameters in the range $26 0^{\circ} \leq γ \leq 27 0^{\circ}$ as examples. The behavior of the SQM as a function of spin $I$ is illustrated by analyzing the components of the total angular momentum. It is found that in the region of chiral vibrations the SQMs of doublet bands are strongly varying with $I$ , whereas in the region of static chirality the SQMs of doublet bands are almost constant. Hence, the measurement of SQMs provides a new criterion for distinguishing the modes of nuclear chirality. Moreover, in the high-spin region the SQMs can be approximated by an analytic formula with a proportionality to $cos γ$ for both doublet bands. This provides a way to extract experimentally the triaxial deformation parameter $γ$ for chiral bands from the measured SQMs.
Comments:
7 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2005.03865 [pdf]
PLB(2020)·22 citations
04
[Submitted on 8 May 2020]
Monopole and dipole transitions of the cluster states of 18O
T. Baba · M. Kimura
On the basis of an extended antisymmetrized molecular dynamics calculation, we study the cluster structure and the of the 0+ and 1- states of 18O. We discuss that several different kinds of cluster states appear in the excitation spectrum, and their monopole and dipole transitions are interesting fingerprints of unique cluster structure. We show that the monopole/dipole transitions are enhanced for the 14C+alpha cluster states, while they are hindered for the molecular-orbit state. We also point out that the ratio of the electric and isoscalar monopole transition strengths gives a good hint for the structure of the excited states.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2005.03934 [pdf]
PRC(2020)·7 citations
05
[Submitted on 8 May 2020]
Extracting a model quark propagator's spectral density
Zehao Zhu🇨🇳 · Khépani Raya🇨🇳 · Lei Chang🇨🇳
We propose a practical procedure to extrapolate the space-like quark propagator onto the complex plane, which follows the Schlessinger Point Method and the spectral representation of the propagator. As a feasible example, we employ quark propagators for different flavors, obtained from the solutions of the corresponding Dyson-Schwinger equation (DSE). Two different truncations are employed. Thus, the analytical structure of the quark propagator is studied, capitalizing on the current-quark mass dependence of the observed features.
Comments:
8 pages, 6 figures. It includes a new example with a beyond Rainbow-Ladder truncation
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2005.04181 [pdf]
PRD(2021)·3 citations
06
[Submitted on 7 May 2020] (cross-list from nucl-ex)
Coulomb excitation of the $∣ T_{z} ∣ = \frac{1}{2}$ , $A = 23$ mirror pair
J. Henderson · G. Hackman · P. Ruotsalainen · J. D. Holt · S. R. Stroberg · C. Andreoiu · G. C. Ball · N. Bernier · M. Bowry · R. Caballero-Folch · S. Cruz · A. Diaz Varela and 14 other authors
Background: Electric-quadrupole ( $E 2$ ) strengths relate to the underlying quadrupole deformation of a nucleus and present a challenge for many nuclear theories. Mirror nuclei in the vicinity of the line of $N = Z$ represent a convenient laboratory for testing deficiencies in such models, making use of the isospin-symmetry of the systems. Purpose: Uncertainties associated with literature $E 2$ strengths in \textsuperscript{23}Mg are some of the largest in $T_{z} = \frac{1}{2}$ nuclei in the $s d$ -shell. The purpose of the present work is to improve the precision with which these values are known, to enable better comparison with theoretical models. Methods: Coulomb-excitation measurements of $^{23}$ Mg and $^{23}$ Na were performed at the TRIUMF-ISAC facility using the TIGRESS spectrometer. They were used to determine the $E 2$ matrix elements of mixed $E 2$ / $M 1$ transitions. Results: Reduced $E 2$ transition strengths, $B (E 2)$ , were extracted for \textsuperscript{23}Mg and \textsuperscript{23}Na. Their precision was improved by factors of approximately six for both isotopes, while agreeing within uncertainties with previous measurements. Conclusions: A comparison was made with both shell-model and {\it ab initio} valence-space in-medium similarity renormalization group calculations. Valence-space in-medium similarity-renormalization-group calculations were found to underpredict the absolute $E 2$ strength - in agreement with previous studies.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.03796 [pdf]
PRC(2022)·19 citations
07
[Submitted on 8 May 2020] (cross-list from nucl-ex)
Precision measurement of the $E 2$ transition strength to the 2 $_{1}^{+}$ state of $^{12}$ C
A. D'Alessio · T. Mongelli · M. Arnold · S. Bassauer · J. Birkhan · M. Hilcker · T. Hüther · J. Isaak · L. Jürgensen · T. Klaus · P. von Neumann-Cosel · N. Pietralla and 7 other authors
The form factor of the electromagnetic excitation of $^{12}$ C to its 2 $_{1}^{+}$ state was measured at extremely low momentum transfers in an electron scattering experiment at the S-DALINAC. A combined analysis with the world form factor data results in a reduced transition strength $B (E 2; 2_{1}^{+} \to 0_{1}^{+}) = 7.63 (19)$ e $^{2}$ fm $^{4}$ with an accuracy improved to 2.5\%. In-Medium-No Core Shell Model results with interactions derived from chiral effective field theory are capable to reproduce the result. A quadrupole moment $Q (2_{1}^{+}) = 5.97 (30)$ efm $^{2}$ can be extracted from the strict correlation with the $B ((E 2)$ strength emerging in the calculations.
Comments:
6 pages, 6 figures, submitted to Phys. Rev. C
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.04072 [pdf]
PRC(2020)·16 citations
08
[Submitted on 8 May 2020] (cross-list from nucl-ex)
Evolution of the dipole polarizability in the stable tin isotope chain
S. Bassauer (1) · P. von Neumann-Cosel (1) · P.-G. Reinhard (2) · A. Tamii (3) · S. Adachi (3) · C. A. Bertulani (4) · P. Y. Chan (3) · G. Colò (5) · A. D'Alessio (1) · H. Fujioka (6) · H. Fujita (3) · Y. Fujita (3) and 27 other authors
The dipole polarizability of stable even-mass tin isotopes 112,114,116,118,120,124 was extracted from inelastic proton scattering experiments at 295 MeV under very forward angles performed at RCNP. Predictions from energy density functionals cannot account for the present data and the polarizability of 208Pb simultaneously. The evolution of the polarizabilities in neighboring isotopes indicates a kink at 120Sn while all model results show a nearly linear increase with mass number after inclusion of pairing corrections.
Comments:
10 pages, 6 figures, submitted to Phys. Lett. B
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.04105 [pdf]
PLB(2020)·28 citations

Affiliations

first authorsco-authorsvia INSPIRE