Role of cluster structure in the breakup of Li7

Direct and sequential breakups of the projectile in the $^{7}\mathrm{Li}+^{112}\mathrm{Sn}$ reaction have been measured at a beam energy of 30 MeV. Cross sections for sequential breakup of $^{7}\mathrm{Li}$ into $\ensuremath{\alpha}$ and $t$ cluster fragments via its second resonant state of $5/{2}^{\ensuremath{-}}$ (6.68 MeV) in the continuum have been measured for the first time along with the first resonant state ($7/{2}^{\ensuremath{-}}$, 4.63 MeV). Probabilities of sequential breakup proceeding through $\ensuremath{-}1n$ and $\ensuremath{-}2n$ transfer channels, i.e., ($^{7}\mathrm{Li},^{6}\mathrm{Li}$) and ($^{7}\mathrm{Li},^{5}\mathrm{Li}$) reactions followed by breakup, into $\ensuremath{\alpha}+d$ and $\ensuremath{\alpha}+p$, respectively, were found to dominate over $\ensuremath{\alpha}+t$ breakup. Measured cross sections for the above breakup channels and elastic scattering have been compared with coupled-channel calculations to understand the reaction mechanism involving the weakly bound projectile $^{7}\mathrm{Li}$. Significant cross section for direct breakup of $^{7}\mathrm{Li}\ensuremath{\rightarrow}^{6}\mathrm{He}+p$ has also been measured for the first time, indicating the importance of the new ($^{6}\mathrm{He}+p$) cluster configuration that may be necessary to understand the complete structure of $^{7}\mathrm{Li}$ and its energy levels.