The ³ He+ ⁵ He → α + α reaction below the Coulomb barrier via the Trojan Horse Method

For the first time in an application to nuclear astrophysics, a process induced by the unstable ⁵He = (⁴He-n) nucleus, the ³He+⁵He→ 2α reaction, has been studied through the Trojan Horse Method (THM). For that purpose, the quasi-free (QF) contribution of the ⁹Be(³He,αα)⁴He reaction was selected at E3He=4 MeV incident energy. The reaction was studied in a kinematically complete experiment following a recent publication (Spitaleri et al. in Eur Phys J A 56:18, 2020), where for the quasi free contribution the momentum distribution between α and ⁵He particle cluster in the ⁹Be nucleus in the ground state have been extracted. The angular distribution of the QF ³He+⁵He→ 2α reaction was measured at θ_cm = 78^∘–115^∘. The energy dependence of the differential cross section of the ³He+⁵He→ 2α virtual reaction was extracted in the energy range E_cm = 0–650 keV. The total cross section obtained from the Trojan-horse method was normalized to absolute cross sections from a theoretical calculation in the energy range E_cm =300–620 keV.