7Li(3He, p)9Be Reaction and primordial nucleosynthesis

Rath, Dipti P.; Boyd, R. N.; Hausman, H.J.; Islam, M. S.; Kolnicki, G.W.

doi:10.1016/0375-9474(90)90371-r

Cited by 20 publications

(22 citation statements)

References 28 publications

(18 reference statements)

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“…At energies below 100 keV, where this reaction is relevant to BBN, the S-factor is essentially flat at 5.3 MeV-barn. In addition, from the spectrum [40] it can be inferred that the reaction to excited and continuum states is roughly a factor of five greater than that to ground state. Therefore the assumed rates, in units of cm 3 Although this reaction makes 6 He, its ground state β-decays with a half-life of 807 ms to 6 Li.…”

Section: A Comments On the Added Nuclear Reaction Ratesmentioning

confidence: 99%

“…Accordingly, in the absence of better information, we have simply assumed the same rate for this reaction as for the These reactions go to a variety of states in 9 B, all of which decay by proton emission, including the ground state. Since these are deuteron transfer reactions, and have comparable (large) Q-values to that for the 7 Li( 3 H,n) reaction, we assumed the same astrophysical S-factor for it to the 9 B ground state as for 7 Li( 3 H,n) 9 Be(ground state) [39] (including more than the leading term does not seem justifiable), and noted [40] that the 7 Li( 3 He,p) 9 Be yield to all states appeared to be greater than that to the ground state by approximately a factor of five. After appropriate corrections for the nuclear charges [38], the assumed rates are 6 Li, was not included in the reaction network, as it was found [54] to have a much smaller cross section than 9 Be(p, 4 He) 6 Li, and it depends on the 9 Be abundance, which is small in BBN.…”

Section: A Comments On the Added Nuclear Reaction Ratesmentioning

confidence: 99%

“…The reaction to the ground state gives one neutron, whereas those to all the excited states give two neutrons due to the breakup of all 9 Be excited states into two α-particles and a neutron. The relevant rates [39] are: The first reaction was studied at higher energies [40], and extended to lower energies [41], and an S-factor was determined for the reaction to the 9 Be(ground state). Although the S-factor exhibits a broad resonance structure, the resonances exist at relatively high energies.…”

Section: A Comments On the Added Nuclear Reaction Ratesmentioning

confidence: 99%

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New nuclear physics for big bang nucleosynthesis

et al. 2010

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We discuss nuclear reactions which could play a role in Big Bang Nucleosynthesis (BBN). Most of these reactions involve lithium and beryllium isotopes and the rates for some of these have not previously been included in BBN calculations. Few of these reactions are well studied in the laboratory. We also discuss novel effects in these reactions, including thermal population of nuclear target states, resonant enhancement, and non-thermal neutron reaction products. We perform sensitivity studies which show that even given considerable nuclear physics uncertainties, most of these nuclear reactions have minimal leverage on the standard BBN abundance yields of 6 Li and 7 Li. Although a few have the potential to alter the yields significantly, we argue that this is unlikely.

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Section: A Comments On the Added Nuclear Reaction Ratesmentioning

confidence: 99%

Section: A Comments On the Added Nuclear Reaction Ratesmentioning

confidence: 99%

Section: A Comments On the Added Nuclear Reaction Ratesmentioning

confidence: 99%

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New nuclear physics for big bang nucleosynthesis

et al. 2010

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“…A, =l to the observed cross sections at 28 different energies by the g -fitting method, where 28 is the number of observed data [6] for the energy range 0 ( E, (2.0 MeV.…”

Section: Coe+cients Cq 'Smentioning

confidence: 99%

“…Although the high-energy data of this reaction cross section have been accumulated in the past in order to study the reaction mechanism of twonucleon transfer, low-energy cross sections also have recently been measured [6] for astrophysical application. The two reactions Li( H, n) Be and Li( He,p) Be have several similarities in the reaction dynamics if the isospin symmetry holds approximately true in the nuclear interaction, except for a major difference arising from the Coulomb interaction.…”

Section: Introductionmentioning

confidence: 99%

Reaction mechanism ofLi7(3
Yamamoto
¹
,
Kajino
²
,
Kubo
³

1993
Phys. Rev. C
11
0
1
0
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We investigate in a unified way the reaction mechanism of Li('H, n ) Be and Li( He, p) Be at the low energies E, 2 MeV of astrophysical interest. Assuming charge independence of the nuclear reaction amplitudes and taking account of the effects from different isospin contribution, Coulomb interaction, and associated kinematical conditions properly, we constrain the upper and lower bounds of the total cross section of 'Li( H, n ) Be theoretically by using knowledge of the Li('He, p) Be reaction. It is found that the total cross section of Li( H, n ) Be at Gamow window energy E -250 keV is dominated by the near-threshold T=1 resonance whose resonance parameters are not determined at all experimentally, although the direct reaction process makes progressively important contributions at higher energies 500 keV~E, . Primordial abundance of Be calculated in the inhomogeneous and standard big-bang models by using the inferred reaction cross section for Li( H, n) Be is compared with recent results of astronomical observations. PACS number(s): 98.80.Ft, 25.55.Hp energies. It has been shown in the analyses [7] of the Li( He,p) Be reaction that the knock-on mechanism is significant. They have also shown that the cancellation assumption, which is usually employed in the DWBA method, is inadequate. Following the same line as Werby and Edwards had for the Li( He,p) Be reaction, we will concentrate on examining whether their results are still correct for the Li( H, n) Be reaction in question. Through these studies we will meet the challenge of predicting the Li( H, n) Be reaction cross section by using all the detailed information on the Li( He,p) Be reaction data.

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