Estimation of 
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 scissors mode strength for deformed nuclei in the medium- to heavy-mass region by statistical Hauser-Feshbach model calculations

Mumpower, Matthew; Kawano, Toshihiko; Ullmann, J. L.; Krtička, M.; Sprouse, Trevor

doi:10.1103/physrevc.96.024612

Cited by 55 publications

(39 citation statements)

References 65 publications

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“…For such calculations, there are several models and parameter sets that can be chosen from literature, and typically the spread in calculated cross sections may vary within factors of ≈ 5 − 10. To quantitatively determine this spread, Escher et al [268] have tested the sensitivity of the calculations using several input options [113,110,271,272,273]. The resulting systematic-error band is shown in panel (f) of Fig.…”

Section: Surrogate Reaction Methods For Statistical Capturementioning

confidence: 99%

Novel techniques for constraining neutron-capture rates relevant for r-process heavy-element nucleosynthesis

Larsen

Spyrou

Liddick

et al. 2019

Progress in Particle and Nuclear Physics

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The rapid-neutron capture process (r process) is identified as the producer of about 50% of elements heavier than iron.This process requires an astrophysical environment with an extremely high neutron flux over a short amount of time (∼ seconds), creating very neutron-rich nuclei that are subsequently transformed to stable nuclei via β − decay. In 2017, one site for the r process was confirmed: the advanced LIGO and advanced Virgo detectors observed two neutron stars merging, and immediate follow-up measurements of the electromagnetic transients demonstrated an "afterglow" over a broad range of frequencies fully consistent with the expected signal of an r process taking place. Although neutronstar mergers are now known to be r-process element factories, contributions from other sites are still possible, and a comprehensive understanding and description of the r process is still lacking. One key ingredient to large-scale r-process reaction networks is radiative neutron-capture (n, γ) rates, for which there exist virtually no data for extremely neutronrich nuclei involved in the r process. Due to the current status of nuclear-reaction theory and our poor understanding of basic nuclear properties such as level densities and average γ-decay strengths, theoretically estimated (n, γ) rates may vary by orders of magnitude and represent a major source of uncertainty in any nuclear-reaction network calculation of rprocess abundances. In this review, we discuss new approaches to provide information on neutron-capture cross sections and reaction rates relevant to the r process. In particular, we focus on indirect, experimental techniques to measure radiative neutron-capture rates. While direct measurements are not available at present, but could possibly be realized in the future, the indirect approaches present a first step towards constraining neutron-capture rates of importance to the r process.

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Section: Surrogate Reaction Methods For Statistical Capturementioning

confidence: 99%

Novel techniques for constraining neutron-capture rates relevant for r-process heavy-element nucleosynthesis

Larsen

Spyrou

Liddick

et al. 2019

Progress in Particle and Nuclear Physics

View full text Add to dashboard Cite

show abstract

“…This network uses state-of-the-art nuclear physics inputs (e.g. Mumpower et al 2016Mumpower et al , 2017Möller et al 2019), including a robust treatment of capture rates as well as neutron-induced and β-delayed fission using a single theoretical framework (Mumpower et al 2018). Variation in uncertain nuclear properties, such as those from nuclear binding energies proceeds as in Mumpower et al (2015).…”

Section: Gamma-rays From R-process Yieldsmentioning

confidence: 99%

Gamma Rays from Kilonova: A Potential Probe of r-process Nucleosynthesis

Korobkin

Hungerford

Fryer

et al. 2020

ApJ

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The mergers of compact binaries with at least one neutron star component have been recently recognized as the potential leading sites of the production and ejection of r-process elements. Discoveries of galactic binary pulsars, short gamma-ray bursts and gravitational wave detections have all been constraining the rate of these events while the gravitational wave plus broadband electromagnetic coverage of binary neutron-star merger (GW170817) has also placed constraints on the properties (mass and composition) of the merger ejecta. But uncertainties and ambiguities in modeling the optical and infra-red emission make it difficult to definitively measure the distribution of heavy isotopes in these mergers. In contrast, gamma-rays emitted in the decay of these neutron-rich ejecta may provide a more direct measurement of the yields. We calculate the gamma production in remnants of neutron star mergers, considering two epochs: a kilonova epoch, lasting about two weeks, and a much later epoch of tens and hundreds of thousands of years after the merger. For the kilonova epoch, when the expanding ejecta is still only partially transparent to gamma radiation, we use 3D radiative transport simulations to produce the spectra. We show that the gamma-ray spectra associated with beta-and alpha-decay provide a fingerprint of the ejecta properties and, for a sufficiently nearby remnant, may be detectable, even for old remnants. We compare our gamma spectra to the potential detection limits of next generation detectors, including LOX, AMEGO and COSI.

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“…An indirect Coulomb-dissociation measurement by Uberseder et al (2014) places constraints on the gamma-ray strength function used in the statistical crosssection calculation, however, this measurement was only sensitive to E1 components. There is growing evidence that the M1 component, not accessible in the Uberseder measurement, play an important role in neutron capture cross sections (Larsen & Goriely 2010;Mumpower et al 2017). Finally, neutron capture cross sections on isotopes near shell closures, such as 59 Fe, are notoriously difficult to predict because individual neutron resonances can dominate the nuclear reaction rate.…”

Section: Post-processing Nucleosynthesis Codementioning

confidence: 99%

60Fe in core-collapse supernovae and prospects for X-ray and gamma-ray detection in supernova remnants

Jones

Möller

Fryer

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We investigate 60 Fe in massive stars and core-collapse supernovae focussing on uncertainties that influence its production in 15, 20 and 25 M stars at solar metallicity. We find that the 60 Fe yield is a monotonic increasing function of the uncertain 59 Fe(n, γ) 60 Fe cross section and that a factor of 10 reduction in the reaction rate results in a factor 8-10 reduction in the 60 Fe yield; while a factor of 10 increase in the rate increases the yield by a factor 4-7. We find that none of the 189 simulations we have performed are consistent with a core-collapse supernova triggering the formation of the Solar System, and that only models using 59 Fe(n, γ) 60 Fe cross section that is less than or equal to that from NON-SMOKER can reproduce the observed 60 Fe/ 26 Al line flux ratio in the diffuse ISM. We examine the prospects of detecting old core-collapse supernova remnants (SNRs) in the Milky Way from their γ-ray emission from the decay of 60 Fe, finding that the next generation of gamma-ray missions could be able to discover up to ∼ 100 such old SNRs as well as measure the 60 Fe yields of a handful of known Galactic SNRs. We also predict the X-ray spectrum that is produced by atomic transitions in 60 Co following its ionization by internal conversion and give theoretical X-ray line fluxes as a function of remnant age as well as the Doppler and fine-structure line broadening effects. The X-ray emission presents an interesting prospect for addressing the missing SNR problem with future X-ray missions.

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Estimation of M1 scissors mode strength for deformed nuclei in the medium- to heavy-mass region by statistical Hauser-Feshbach model calculations

Cited by 55 publications

References 65 publications

Novel techniques for constraining neutron-capture rates relevant for r-process heavy-element nucleosynthesis

Novel techniques for constraining neutron-capture rates relevant for r-process heavy-element nucleosynthesis

Gamma Rays from Kilonova: A Potential Probe of r-process Nucleosynthesis

60Fe in core-collapse supernovae and prospects for X-ray and gamma-ray detection in supernova remnants

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