Fission cycling in a supernova<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>r</mml:mi></mml:mrow></mml:math>process

Beun, J.A.; McLaughlin, G. C.; Surman, Rebecca; Hix, W. R.

doi:10.1103/physrevc.77.035804

Cited by 57 publications

(60 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The abundances of several isotopes ( 86 Sr, 93 Nb, 96 Mo, 100 Ru, 104 Pd, 110 Cd) could not be explained by adding s-and r-process (as observed in UMP stars) contributions. They suggested that these isotopes are produced by the Lighter Element Primary Process (LEPP), but they did not specify the astrophysical site nor the nuclear reactions involved.…”

Section: Lighter Heavy Elements: Sr Y Zrmentioning

confidence: 85%

Neutrino-driven wind simulations and nucleosynthesis of heavy elements

Arcones

Thielemann

2012

J. Phys. G: Nucl. Part. Phys.

195

201

View full text Add to dashboard Cite

Abstract. Neutrino-driven winds, which follow core-collapse supernova explosions, present a fascinating nuclear astrophysics problem that requires understanding advanced astrophysics simulations, the properties of matter and neutrino interactions under extreme conditions, the structure and reactions of exotic nuclei, and comparisons against forefront astronomical observations. The neutrino-driven wind has attracted vast attention over the last 20 years as it was suggested to be a candidate for the astrophysics site where half of the heavy elements are produced via the r-process. In this review, we summarize our present understanding of neutrino-driven winds from the dynamical and nucleosynthesis perspectives. Rapid progress has been made during recent years in understanding the wind with improved simulations and better micro physics. The current status of the fields is that hydrodynamical simulations do not reach the extreme conditions necessary for the r-process and the proton or neutron richness of the wind remains to be investigated in more detail. However, nucleosynthesis studies and observations point already to neutrino-driven winds to explain the origin of lighter heavy elements, such as Sr, Y, Zr.

show abstract

Section: Lighter Heavy Elements: Sr Y Zrmentioning

confidence: 85%

Neutrino-driven wind simulations and nucleosynthesis of heavy elements

Arcones

Thielemann

2012

J. Phys. G: Nucl. Part. Phys.

195

201

View full text Add to dashboard Cite

show abstract

“…Ref. [64] has suggested that fission cycling contributes to produce a steady β flow equilibrium in which the abundances for each isotopic chain are proportional to the beta-decay half-lives. Steady β flow equilibrium is in fact achieved in NS merger before the r-process freeze-out as the duration of the r process is longer than the individual betadecay half-lives.…”

Section: Evolution Of the R-process Abundances For Fast Ejectamentioning

confidence: 99%

Nuclear robustness of therprocess in neutron-star mergers

et al. 2015

View full text Add to dashboard Cite

We have performed r-process calculations for matter ejected dynamically in neutron star mergers based on a complete set of trajectories from a three-dimensional relativistic smoothed particle hydrodynamic simulation with a total ejected mass of ∼ 1.7 × 10 −3 M . Our calculations consider an extended nuclear network, including spontaneous, β-and neutron-induced fission and adopting fission yield distributions from the ABLA code. In particular we have studied the sensitivity of the r-process abundances to nuclear masses by using different models. Most of the trajectories, corresponding to 90% of the ejected mass, follow a relatively slow expansion allowing for all neutrons to be captured. The resulting abundances are very similar to each other and reproduce the general features of the observed r-process abundance (the second and third peaks, the rare-earth peak and the lead peak) for all mass models as they are mainly determined by the fission yields. We find distinct differences in the predictions of the mass models at and just above the third peak, which can be traced back to different predictions of neutron separation energies for r-process nuclei around neutron number N = 130. In all simulations, we find that the second peak around A ∼ 130 is produced by the fission yields of the material that piles up in nuclei with A 250 due to the substantially longer beta-decay half-lives found in this region. The third peak around A ∼ 195 is generated in a competition between neutron captures and β decays during r-process freeze-out. The remaining trajectories, which contribute 10% by mass to the total integrated abundances, follow such a fast expansion that the r process does not use all the neutrons. This also leads to a larger variation of abundances among trajectories as fission does not dominate the r-process dynamics. The resulting abundances are in between those associated to the r and s processes. The total integrated abundances are dominated by contributions from the slow abundances and hence reproduce the general features of the observed r-process abundances. We find that at timescales of weeks relevant for kilonova light curve calculations, the abundance of actinides is larger than the one of lanthanides. This means that actinides can be even more important than lanthanides to determine the photon opacities under kilonova conditions. Moreover, we confirm that the amount of unused neutrons may be large enough to give rise to another observational signature powered by their decay.

show abstract

“…The analysis is expanded in [54] with the inclusion of fission cycling of the produced heavy elements. The analysis indicates the need for an eV-scale sterile neutrino with an allowed parameter space much larger than that constrained by LSND.…”

Section: Supernova Nucleosynthesismentioning

confidence: 99%

Neutrino phenomenology of very low-energy seesaw scenarios

2007

View full text Add to dashboard Cite

The Standard Model augmented by the presence of gauge-singlet right-handed neutrinos proves to be an ideal scenario for accommodating nonzero neutrino masses. Among the new parameters of this "New Standard Model" are right-handed neutrino Majorana masses M . Theoretical prejudice points to M much larger than the electroweak symmetry breaking scale, but it has recently been emphasized that all M values are technically natural and should be explored. Indeed, M around 1 − 10 eV can accommodate an elegant oscillation solution to the LSND anomaly, while other M values lead to several observable consequences. We consider the phenomenology of low energy (M 1 keV) seesaw scenarios. By exploring such a framework with three right-handed neutrinos, we can consistently fit all oscillation data -including those from LSND -while partially addressing several astrophysical puzzles, including anomalous pulsar kicks, heavy element nucleosynthesis in supernovae, and the existence of warm dark matter. Furthermore, low-energy seesaws -regardless of their relation to the LSND anomaly -can also be tested by future tritium beta-decay experiments, neutrinoless double-beta decay searches, and other observables. We estimate the sensitivity of such probes to M .

show abstract

Fission cycling in a supernovarprocess

Cited by 57 publications

References 76 publications

Neutrino-driven wind simulations and nucleosynthesis of heavy elements

Neutrino-driven wind simulations and nucleosynthesis of heavy elements

Nuclear robustness of therprocess in neutron-star mergers

Neutrino phenomenology of very low-energy seesaw scenarios

Contact Info

Product

Resources

About