Microscopic approach based on a multiscale algebraic version of the resonating group model for radiative capture reactions

Background: The production of 7 Be and 7 Li nuclei plays an important role in primordial nucleosynthesis, nuclear astrophysics, and fusion energy generation. The 3 He(α, γ) 7 Be and 3 H(α, γ) 7 Li radiative-capture processes are important to determine the 7 Li abundance in the early universe and to predict the correct fraction of pp-chain branches resulting in 7 Be versus 8 B neutrinos. The 6 Li(p, γ) 7 Be has been investigated recently hinting at a possible cross section enhacement near the thershold. The 6 Li(n, 3 H) 4 He process can be utilized for tritium breeding in machines dedicated to fusion energy generation through the deuteron-tritium reaction, and is a neutron cross section standard used in the measurement and evaluation of fission cross sections. Purpose: In this work we study the properties of 7 Be and 7 Li within the no-core shell model with continuum (NCSMC) method, using chiral nucleon-nucleon interactions as the only input, and analyze all the binary mass partitions involved in the formation of these systems. Methods: The NCSMC is an ab initio method applicable to light nuclei that provides a unified description of bound and scattering states and thus is well suited to investigate systems with many resonances and pronounced clustering like 7 Be and 7 Li. Results: Our calculations reproduce all the experimentally known states of the two systems and provide predictions for several new resonances of both parities. Some of these new possible resonances are built on the ground states of 6 Li and 6 He, and thus represent a robust prediction. We do not find any resonance in the p+ 6 Li mass partition near the threshold. On the other hand, in the p+ 6 He mass partition of 7 Li we observe an S-wave resonance near the threshold producing a very pronounced peak in the calculated S factor of the 6 He(p, γ) 7 Li radiative-capture reaction. Conclusions: While we do not find a resonance near the thershold in the p+ 6 Li channel, in the case of 6 He+p reaction a resonant S-wave state is predicted at a very low energy above the reaction threshold, which could be relevant for astrophysics and its implications should be investigated. We note though that this state lies above the three-body breakup threshold not included in our method and may be influenced by three-body continuum correlations.

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“…of the 3 He(α, γ) 7 Be and 3 H(α, γ) 7 Li radiative-capture processes [20][21][22][23][24][25][26][27][28][29][30][31]. In particular, in Ref.…”

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confidence: 99%

Be7 and Li7 nuclei within the no-core shell model with continuum

et al. 2019

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“…The latter reaction is also important to study stellar nucleosynthesis, especially in the Sun. Despite a long story of experimental and theoretical investigations of these reactions (see references cited in works [1,2]), the required precision has not been achieved yet. As a result, the problems still remain.…”

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confidence: 99%

The ³ H(α, γ)⁷ Li and ³He(α, γ)⁷ Be Radiative Capture Reactions in a Wide Energy Range

Solovyev

2019

EPJ Web Conf.

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The mirror 3 H(α, γ)7 Li and 3 He(α, γ)7 Be reactions are considered from the microscopic viewpoint within a developed approach based on the multiscale algebraic version of the resonating group model. The total astrophysical S factors and the branching ratios for these reactions are calculated at low and intermediate energies covering the lowest resonances of the final fused nuclei. The results from the calculations are in an agreement with data from experiments.

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“…The 7 Be production in the process 3 Не( 4 Не,) 7 Bе is used directly for estimating the formation of 7 Li as a result of  -decay. Data on this process are used for the calculation of the lithium isotopes ratio 6 Li/ 7 Li produced in the Big Bang. The recent data on the 6 Li/ 7 Li isotopic ratio obtained within the framework of the LUNA collaboration and a detailed discussion of the astrophysical aspects of this problem are reported in [4].…”

Section: Introductionmentioning

confidence: 99%

“…The recent data on the 6 Li/ 7 Li isotopic ratio obtained within the framework of the LUNA collaboration and a detailed discussion of the astrophysical aspects of this problem are reported in [4]. The experimental status of the 3 Не( 4 Не,) 7 Bе reaction is critically reviewed, and the available theoretical descriptions of the production and destruction of 7 Be at astrophysical energies are discussed in [5] and [6].…”

Section: Introductionmentioning

confidence: 99%

Potential cluster calculations for the astrophysical S-factor and reaction rate of the radiative 3He(4He,γ)7Be capture

Dubovichenko¹,

Burkova²,

Dzhazairov-Kakhramanov³

2018

Indian J Phys

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In the frame of a modified potential cluster model based on the classification of orbital states according to Young diagrams and revised interaction potential parameters for the bound states of 7 Be in the 3 He 4 He cluster model with forbidden states, the astrophysical S-factor for the radiative capture reaction 3 Не( 4 Не,) 7 Bе has been calculated from 10 keV. The result obtained, S(23 keV) = 0.561 keVb, reproduces the latest experimental data at 23 keV. The calculated and parametrized reaction rate is compared with some known results in the range of temperatures from 0.05 to 5T9.

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Microscopic approach based on a multiscale algebraic version of the resonating group model for radiative capture reactions

Cited by 16 publications

References 123 publications

Be7 and Li7 nuclei within the no-core shell model with continuum

Be7 and Li7 nuclei within the no-core shell model with continuum

The ³ H(α, γ)⁷ Li and ³He(α, γ)⁷ Be Radiative Capture Reactions in a Wide Energy Range

Potential cluster calculations for the astrophysical S-factor and reaction rate of the radiative 3He(4He,γ)7Be capture

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Microscopic approach based on a multiscale algebraic version of the resonating group model for radiative capture reactions

Cited by 16 publications

References 123 publications

Be7 and Li7 nuclei within the no-core shell model with continuum

Be7 and Li7 nuclei within the no-core shell model with continuum

The 3 H(α, γ)7 Li and 3He(α, γ)7 Be Radiative Capture Reactions in a Wide Energy Range

Potential cluster calculations for the astrophysical S-factor and reaction rate of the radiative 3He(4He,γ)7Be capture

Contact Info

Product

Resources

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The ³ H(α, γ)⁷ Li and ³He(α, γ)⁷ Be Radiative Capture Reactions in a Wide Energy Range