Toward correction-free⁸Li(α,n)¹¹B data at the Gamow energy of explosive nucleosynthesis

Abstract

Abstract. The8 Li+ 4 He → 11 B+n reaction inside the center of mass energy region E cm = 0.5 − 2.5 MeV, corresponding to the temperature range T 9 = 1 − 5, is of relevant interest in the fields of nuclear cosmology and nuclear astrophysics. In the context of Big-Bang nucleosynthesis, it has been invoked to overcome the A=8 mass gap; in r-process nucleosynthesis, it is considered a candidate precursor of seed nuclei. In this experimental work, the cross section, summed over all 11 B final bound states, at the energy of 1.05 MeV in the center-of-mass system, is investigated by a correction-free projectile-correlated inclusive neutron measurement. The radioactive 8 Li beam delivered by the EXCYT facility at LNS-Catania is used to induce the inversekinematics reaction process. A zero-energy-threshold 4π detection system is used. Thanks to the improved experimental and analysis procedures, the result obtained in this work represents a strong argument to reopen the debate on the magnitude of the 8 Li(α, n) 11 B reaction rate in explosive astrophysical environments.PACS numbers: 25.60. -t,26.30.-k,26.35.+c

The8Li(p,α)5He reaction at low energies, andMendes1, Lépine‐Szily2, Descouvemont3 et al. 2012Phys. Rev. C

“…Although the 8 Li(α, n) 11 B cross section has been measured by several groups (see Ref. [10] and references therein) there is still a significant discrepancy between the measurements (see, for example, Fig. 4 of Ref.…”

“…[9] and references therein) and has been investigated by various groups (see, for example, Ref. [10] and references therein). More recently, it was suggested that this reaction could also affect r-process nucleosynthesis [11].…”

Spectroscopy of high lying resonances in9Be produced with radioactive8Li beams

“…Also, radioactive beams provide a probe of the nuclear structure, in unusual conditions of excitation energy and isospin. Many experiments have been performed in recent decades with various beams of halo nuclei such as 6 He, 11 Be, 8 He or 11 Li (see references in Ref. [2]).…”

“…In particular, the 8 Li(α,n) 11 B reaction could affect the non-standard Big-Bang nucleosynthesis (see Ref.…”

“…[11] and references therein). More recently, it was also suggested that this reaction could be the seed for r-process nucleosynthesis [12].…”