Sequential breakup of 6Li via (6Li, 5He → α + n ) reaction

We report an experimental investigation of an unexplored breakup pathway of 6 Li proceeding via one-proton stripping to the unbound 5 He nucleus, followed by its decay into α + n , in the 6 Li + 112 Sn reaction at E b e a m = 30 MeV. Coincident α - n events were measured using an array of silicon strip telescopes in conjunction with liquid scintillator neutron detectors. Successive kinematical cuts on the reconstructed projectile-like, fragment energies and Q-values enabled a clear separation of contributions arising purely through 5 He → α + n from competing processes such as evaporation following complete and incomplete fusion. The resultant relative energy distributions exhibit a pronounced peak at 0.84 MeV, indicating sequential breakup through the first unbound resonance 5 He(3/2 − ) and show good agreement with Monte-Carlo simulations. Absolute breakup cross-sections for the ( 6 Li, 5 He → αn ) channel are determined using the efficiency-corrected yields. In addition, angular distributions for elastic scattering and breakup cross sections are interpreted within coupled-channels (CDCC+CRC) framework. The present results provide valuable insight into transfer-induced breakup dynamics of weakly bound nuclei near the Coulomb barrier.