Nuclear Theory·nucl-th

Friday·May 29, 2015

9 papers—5 primary·4 cross-listed

01
[Submitted on 27 May 2015]
Modeling nuclear weak-interaction processes with relativistic energy density functionals
N. Paar🇨🇭 · T. Marketin🇭🇷 · D. Vale🇭🇷 · D. Vretenar🇭🇷
Relativistic energy density functionals have become a standard framework for nuclear structure studies of ground-state properties and collective excitations over the entire nuclide chart. We review recent developments in modeling nuclear weak-interaction processes: charge-exchange excitations and the role of isoscalar proton-neutron pairing, charged-current neutrino-nucleus reactions relevant for supernova evolution and neutrino detectors, and calculation of beta-decay rates for r-process nucleosynthesis.
Comments:
22 pages, 12 figures, submitted for publication
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
arXiv:
1505.07486 [pdf]
IJMPE(2015)·12 citations
02
[Submitted on 28 May 2015]
Electric Characteristics of Rotational States positive parity in isotopes 170,172,174Yb
P.N.Usmanov · A.A.Okhunov · H. Abu Kassim · U.S. Salikhbaev
Accounting for Coriolis mixing of experimentally known rotational bands with $K^{π} < 3^{+}$ , non-adiabatic effects in energy and electric characteristics of excited states are investigated, within phenomenological model. The energy and wave function structure of excited states are calculated. The finding reveals that the bands mixing has been found to have considerable impact on the wave function of low-lying states $0^{+}$ and $2^{+}$ bands. In addition, the probabilities of $E 2$ -- transitions have been calculated. The values from calculations of $B (E 2)$ -- transitions from $0_{2}^{+}$ , $0_{3}^{+}$ , $2_{1}^{+}$ , and $2_{2}^{+}$ bands are compared with the experimental data.
Comments:
11 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1505.07527 [pdf]
0 citations
03
[Submitted on 28 May 2015]
Sensitivity of $β$ -decay rates to the radial dependence of the nucleon effective mass
A. P. Severyukhin · Jérôme Margueron (IPNL) · I. N. Borzov · Nguyen Van Giai (IPNO)
We analyze the sensitivity of $β$ -decay rates in 78 Ni and 100,132 Sn to a correction term in Skyrme energy-density functionals (EDF) which modifies the radial shape of the nucleon effective mass. This correction is added on top of several Skyrme parametrizations which are selected from their effective mass properties and predictions about the stability properties of 132 Sn. The impact of the correction on high-energy collective modes is shown to be moderate. From the comparison of the effects induced by the surface-peaked effective mass in the three doubly magic nuclei, it is found that 132 Sn is largely impacted by the correction, while 78 Ni and 100 Sn are only moderately affected. We conclude that $β$ -decay rates in these nuclei can be used as a test of different parts of the nuclear EDF: 78 Ni and 100 Sn are mostly sensitive to the particle-hole interaction through the B(GT) values, while 132 Sn is sensitive to the radial shape of the effective mass. Possible improvements of these different parts could therefore be better constrained in the future.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1505.07559 [pdf]
PRC(2015)·7 citations
04
[Submitted on 28 May 2015]
Microscopic evaluation of the hypernuclear chart with $Λ$ -hyperons
E. Khan🇫🇷 · J. Margueron🇫🇷 · F. Gulminelli🇫🇷 · Ad. R. Raduta🇷🇴
A large number of hypernuclei, where a considerable fraction of nucleons is replaced by strange baryons, and even pure hyperonic species are expected to be bound. Though, the hypernuclear landscape remains largely unknown because of scarce constraints on the $N Y$ and $Y Y$ interactions. We want to estimate the number of potentially bound hypernuclei. In order to evaluate realistic error bars within the theoretical uncertainties associated to the spherical mean-field approach, and the present information from already synthetized hypernuclei on the $N - Y$ and $Y - Y$ channels, we limit ourselves to purely $Λ$ -hypernuclei, to magic numbers of $Λ$ 's (for Z $\leq$ 120 and $Λ \leq$ 70), and to even-even-even systems. We consider a density functional approach adjusted to microscopic Bruckner-Hartree-Fock calculations, where the $ΛΛ$ term is corrected in a phenomenological way, to reproduce present experimental constraints. The number of bound even-even-even $Λ$ -hypernuclei is estimated to 491680 $\pm$ 34400. This relatively low uncertainty is due to the fact that the well constrained low density and highly unconstrained high density behavior of the energy functional turn out to be largely decoupled. Results in $Λ$ -hypernuclei appear to be almost independent of the choice for the high-density part of the $ΛΛ$ interaction. The location of the $Λ$ -hyperdriplines is also evaluated. Significant deviations from Iron-Nickel elements can be found for $Λ$ -hypernuclei with the largest binding energy per baryon. Proton, neutron and $Λ$ -hyperon magicity evolution and triple magic $Λ$ -hypernuclei are studied. Possible bubbles and haloes effect in $Λ$ -hypernuclei are also discussed.
Comments:
16 pages, 16 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1505.07678 [pdf]
PRC(2015)·29 citations
05
[Submitted on 28 May 2015]
The impact of individual nuclear masses on $r$ -process abundances
M. R. Mumpower · R. Surman · D.-L. Fang · M. Beard · P. Moller · T. Kawano · A. Aprahamian
We have performed for the first time a comprehensive study of the sensitivity of $r$ -process nucleosynthesis to individual nuclear masses across the chart of nuclides. Using the latest version (2012) of the Finite-Range Droplet Model, we consider mass variations of $\pm 0.5$ MeV and propagate each mass change to all affected quantities, including $Q$ -values, reaction rates, and branching ratios. We find such mass variations can result in up to an order of magnitude local change in the final abundance pattern produced in an $r$ -process simulation. We identify key nuclei whose masses have a substantial impact on abundance predictions for hot, cold, and neutron star merger $r$ -process scenarios and could be measured at future radioactive beam facilities.
Comments:
8 pages, 3 figures, submitted
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1505.07789 [pdf]
PRC(2015)·98 citations

Affiliations

first authorsco-authorsvia INSPIRE

Modeling nuclear weak-interaction processes with relativistic energy density functionals

Electric Characteristics of Rotational States positive parity in isotopes 170,172,174Yb

Sensitivity of β-decay rates to the radial dependence of the nucleon effective mass

Microscopic evaluation of the hypernuclear chart with Λ-hyperons

The impact of individual nuclear masses on r-process abundances

Affiliations

Sensitivity of $β$ -decay rates to the radial dependence of the nucleon effective mass

Microscopic evaluation of the hypernuclear chart with $Λ$ -hyperons

The impact of individual nuclear masses on $r$ -process abundances