Toward correction-free 8Li(, n)11B data at the Gamow energy of explosive nucleosynthesis

M La Cognata (1, 2) , A del Zoppo (1) , R Alba (1) , S Cherubini (1, 2) , N Colonna (3) , A Di Pietro (1) , P Figuera (1) , M Gulino (1, 2) , L Lamia (1) , A Musumarra (1, 2) , M G Pellegriti (1, 4) , R G Pizzone (1) , C Rolfs (5) , S Romano (1, 2) , C Spitaleri (1, 2) , A Tumino (1, 6)

1 Laboratori Nazionali del Sud
2 Dipartimento di Metodologie Fisiche e Chimiche per l'Ingegneria
3 Sezione di Bari
4 Dipartimento di Fisica e Astronomia [Catania]
5 Institut fur Physik mit Ionenstrahlen
6 Università Kore

The 8 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.

Mots clés: 25.60.-t; 26.30.-k; 26.35.+c

M La Cognata, A del Zoppo, R Alba, S Cherubini, N Colonna, et al.. Toward correction-free 8Li(, n)11B data at the Gamow energy of explosive nucleosynthesis. Journal of Physics G: Nuclear and Particle Physics, 2010, 37 (10), pp.105105. ⟨10.1088/0954-3899/37/10/105105⟩. ⟨hal-00600774⟩