The $$^3$$He+$$^5$$He$$\rightarrow $$ $$\alpha $$+$$\alpha $$ 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 He = (He-n) nucleus, the He+He2 reaction, has been studied through the Trojan Horse Method (THM). For that purpose, the quasi-free (QF) contribution of the Be(He,)He reaction was selected at  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 and He particle cluster in the Be nucleus in the ground state have been extracted. The angular distribution of the QF He+He2 reaction was measured at = 78–115. The energy dependence of the differential cross section of the He+He2 virtual reaction was extracted in the energy range = 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 =300–620 keV.