Nuclear Theory·nucl-th

Thursday·March 28, 2024

11 papers—4 primary·7 cross-listed

01
[Submitted on 27 Mar 2024]
Trineutron resonances in the SS-HORSE-NCSM approach
I. A. Mazur · M. K. Efimenko · A. I. Mazur · I. J. Shin · V. A. Kulikov · A. M. Shirokov · J. P. Vary
The SS-HORSE-NCSM method is generalized to the case of democratic decay into an odd number of fragments. This method is applied to the search for resonances in three-neutron system (trineutron) using ab initio No-Core Shell Model calculations with realistic nucleon-nucleon potentials. The $3/ 2^{-}$ and $1/ 2^{-}$ strongly overlapping resonances are predicted when softened $N N$ interactions are used and are preferred over the case where bare $N N$ interactions of the chiral effective field theory are used with no resonance obtained.
Comments:
7 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2403.18232 [pdf]
PRC(2024)·6 citations
02
[Submitted on 27 Mar 2024]
Nuclear shape evolution of neutron-deficient Au and kink structure of Pb isotopes
Myeong-Hwan Mun · Eunja Ha · Yong-Beom Choi · Myung-Ki Cheoun
Recent experiments using advanced laser spectroscopy technique revealed that the charge radii of neutron-deficient gold (Au) isotopes exhibit significant changes in ground state deformation: odd-even shape staggering in the $N = 98 \sim 100$ region and abrupt change of charge radii from $N =$ 108. In this study, we examine the abnormal shape evolution of the nuclear charge radii. To understand the nuclear structure underlying this phenomenon, we exploit the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). The significant change in mean-squared charge radii ( $δ < r^{2} >$ ) turns out to originate from nuclear shape transitions between prolate deformation and small oblate deformation due to the shape coexistence possibility. We elucidate the nuclear shape evolution by analyzing the evolution of occupation probability for single-particle states. In addition, the abrupt kink structure in the nuclear charge radius of lead (Pb) isotopes near the $N =$ 126 shell is also investigated and reproduced quite well.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2403.18377 [pdf]
PRC(2024)·8 citations
03
[Submitted on 27 Mar 2024]
Uncertainty quantification in $(p, n)$ reactions
A. J. Smith · C. Hebborn · F. M. Nunes · R. G. T. Zegers
Charge-exchange reactions are versatile probes for nuclear structure. In particular, when populating isobaric analog states, these reactions are used to study isovector nuclear densities and neutron skins. The quality of the information extracted from charge-exchange data depends on the accuracy of the reaction models and their inputs; this work addresses these two points. First, we quantify the uncertainties due to effective nucleon-nucleus interactions by propagating the parameter posterior distributions of the recent global optical model KDUQ [1] to $(p, n)$ reaction observables populating the isobaric analogue state, at beam energies in the range of $25 - 160$ MeV. Our analysis, focusing on $^{48}$ Ca, shows that the total parametric uncertainties on the cross sections are around 60-100%. The source of this uncertainty is mainly the transition operator as the uncertainties from the distorted waves alone are less than about 15%. Second, we perform a comparison between two- and three-body models that both describe the dynamics of the reaction within the DWBA. The predictions from these two models are similar and generally agree with the available data, suggesting that 1-step DWBA is sufficient to describe the reaction process. Only at a beam energy of 25 MeV there are possibly signs that a 1-step assumption is not fully correct. This work provides motivation for the quantification of uncertainties associated with the transition operator in three-body model. It also suggests that further constraint of the optical potential parameters is needed for increased model precision.
Comments:
7 pages, 4 figures, Published in Phys. Rev. C 110 034602 (2024)
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2403.18629 [pdf]
PRC(2024)·11 citations
04
[Submitted on 27 Mar 2024]
$p Λ ˉ$ final-state interaction in the reactions $e^{+} e^{-} \to K^{-} p Λ ˉ$ and $J / ψ \to K^{-} p Λ ˉ$
J. Haidenbauer🇩🇪 · U.-G. Meißner🇩🇪
Near-threshold $p Λ ˉ$ mass spectra for the reactions $e^{+} e^{-} \to K^{-} p Λ ˉ$ and $J / ψ \to K^{-} p Λ ˉ$ are investigated with an emphasis on the role played by the interaction in the $p Λ ˉ$ system. As guideline for the $p Λ ˉ$ interaction a variety of $Λ Λ ˉ$ potential models is considered that have been established in the analysis of data on $p p ˉ \to Λ Λ ˉ$ in the past. Arguments why the properties of the $p Λ ˉ$ and $Λ Λ ˉ$ interactions can be expected to be very similar are provided. It is shown that the near-threshold enhancement in the invariant mass observed for the $e^{+} e^{-}$ reaction can be reproduced quantitatively by the assumed $p Λ ˉ$ final-state interaction in the partial wave suggested by an amplitude analysis of the experiment. The effect of the $p Λ ˉ$ final-state interaction in other decays is explored, including the recently measured reactions $B^{-} \to J / ψ p ˉ Λ$ and $B^{+} \to J / ψ p Λ ˉ$ . It is found that the final-state interaction improves the description of the measured invariant mass near threshold in most cases.
Comments:
9 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2403.18706 [pdf]
EPJA(2024)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE

Trineutron resonances in the SS-HORSE-NCSM approach

Nuclear shape evolution of neutron-deficient Au and kink structure of Pb isotopes

Uncertainty quantification in (p,n) reactions

pΛˉ final-state interaction in the reactions e+e−→K−pΛˉ and J/ψ→K−pΛˉ

Affiliations

Uncertainty quantification in $(p, n)$ reactions

$p Λ ˉ$ final-state interaction in the reactions $e^{+} e^{-} \to K^{-} p Λ ˉ$ and $J / ψ \to K^{-} p Λ ˉ$