Facility for Rare Isotope Beams Update for <i>Nuclear Physics News</i>

Glasmacher, T.; Sherrill, B.M.; Nazarewicz, W.; Gade, A.; Mantica, P. F.; Wei, J.; Bollen, G.; Bull, Brad

doi:10.1080/10619127.2017.1317176

Cited by 28 publications

(13 citation statements)

References 5 publications

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“…The ranges of nuclear mass measurements and known nuclei are marked. To provide a representative example of discovery potential of nextgeneration radioactive ion beam facilities, the figure also shows the isotopes that will be accessible at the future Facility for Rare Isotope Beams (FRIB) [54,55].…”

Section: B Landscape Of Nuclear Existencementioning

confidence: 99%

Quantified limits of the nuclear landscape

et al. 2020

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Background: The chart of the nuclides is limited by particle drip lines beyond which nuclear stability to proton or neutron emission is lost. Predicting the range of particle-bound isotopes poses an appreciable challenge for nuclear theory as it involves extreme extrapolations of nuclear masses well beyond the regions where experimental information is available. Still, quantified extrapolations are crucial for a wide variety of applications, including the modeling of stellar nucleosynthesis.Purpose: We use microscopic nuclear global mass models, current mass data, and Bayesian methodology to provide quantified predictions of proton and neutron separation energies as well as Bayesian probabilities of existence throughout the nuclear landscape all the way to the particle drip lines. Methods:We apply nuclear density functional theory with several energy density functionals. We also consider two global mass models often used in astrophysical nucleosynthesis simulations. To account for uncertainties, Bayesian Gaussian processes are trained on the separation-energy residuals for each individual model, and the resulting predictions are combined via Bayesian model averaging. This framework allows to account for systematic and statistical uncertainties and propagate them to extrapolative predictions. Results:We establish and characterize the drip-line regions where the probability that the nucleus is particlebound decreases from 1 to 0. In these regions, we provide quantified predictions for one-and two-nucleon separation energies. According to our Bayesian model averaging analysis, 7759 nuclei with Z ≤ 119 have a probability of existence ≥ 0.5. Conclusions:The extrapolation results obtained in this study will be put through stringent tests when new experimental information on existence and masses of exotic nuclei becomes available. In this respect, the quantified landscape of nuclear existence obtained in this study should be viewed as a dynamical prediction that will be fine-tuned when new experimental information and improved global mass models become available.

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Section: B Landscape Of Nuclear Existencementioning

confidence: 99%

Quantified limits of the nuclear landscape

et al. 2020

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“…The reference values of N 0 (Z) are listed in Tables IV (for even-Z nuclei) and V (for odd-Z nuclei), together with the range of observed nuclei and proton drip-line nuclei. Figure 3 and Tables IV and V also show the isotopes that will be accessible at the future Facility for Rare Isotope Beams (FRIB) [73,74]. FRIB will accelerate ion species up to 238 U with energies of no less than 200 MeV/u (beam power up to 400 kW).…”

Section: Predictions Of Bma Calculations: Quantified Landscape Of mentioning

confidence: 99%

Beyond the proton drip line: Bayesian analysis of proton-emitting nuclei

et al. 2020

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Background: The limits of the nuclear landscape are determined by nuclear binding energies. Beyond the proton drip lines, where the separation energy becomes negative, there is not enough binding energy to prevent protons from escaping the nucleus. Predicting properties of unstable nuclear states in the vast territory of proton emitters poses an appreciable challenge for nuclear theory as it often involves far extrapolations. In addition, significant discrepancies between nuclear models in the proton-rich territory call for quantified predictions.Purpose: With the help of Bayesian methodology, we mix a family of nuclear mass models corrected with statistical emulators trained on the experimental mass measurements, in the proton-rich region of the nuclear chart.Methods: Separation energies were computed within nuclear density functional theory using several Skyrme and Gogny energy density functionals. We also considered mass predictions based on two models used in astrophysical studies. Quantified predictions were obtained for each model using Bayesian Gaussian processes trained on separation-energy residuals and combined via Bayesian model averaging. Results:We obtained a good agreement between averaged predictions of statistically corrected models and experiment. In particular, we quantified model results for one-and two-proton separation energies and derived probabilities of proton emission. This information enabled us to produce a quantified landscape of proton-rich nuclei. The most promising candidates for two-proton decay studies have been identified. Conclusions:The methodology used in this work has broad applications to model-based extrapolations of various nuclear observables. It also provides a reliable uncertainty quantification of theoretical predictions.

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“…so that σ (2) ij,kl represents its fully correlated part. After that, the static kernel takes the form:…”

Section: Equation Of Motion For the Particle-hole Responsementioning

confidence: 99%

Toward an accurate strongly coupled many-body theory within the equation-of-motion framework

Литвинова

Schuck

2019

Phys. Rev. C

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Non-perturbative aspects of the quantum many-body problem are revised, discussed and advanced in the equation of motion framework. We compare the approach to the two-fermion response function truncated on the two-body level by the cluster expansion of the dynamical interaction kernel to the approach known as time blocking approximation. Such a comparison leads to an extended many-body theory with non-perturbative treatment of high-order configurations. The present implementation of the advanced theory introduces a new class of solutions for the response functions, which include explicitly beyond-mean-field correlations between up to six fermions. The novel approach, which includes configurations with two quasiparticles coupled to two phonons (2q⊗2phonon), is discussed in detail for the particle-hole nuclear response and applied to medium-mass nuclei. The proposed developments are implemented numerically on the basis of the relativistic effective mesonnucleon Lagrangian and compared to the models confined by two-fermion and four-fermion configurations, which are considered as the state-of-the-art for the response theory in nuclear structure calculations. The results obtained for the dipole response of 42,48 Ca and 68 Ni nuclei in comparison to available experimental data show that the higher configurations are necessary for a successful description of both gross and fine details of the spectra in both high-energy and low-energy sectors.

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Facility for Rare Isotope Beams Update for Nuclear Physics News

Cited by 28 publications

References 5 publications

Quantified limits of the nuclear landscape

Quantified limits of the nuclear landscape

Beyond the proton drip line: Bayesian analysis of proton-emitting nuclei

Toward an accurate strongly coupled many-body theory within the equation-of-motion framework

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