Intermediate energy four-body breakup calculations for 22C

The heaviest particle-bound carbon isotope, $^{22}$C, is thought to have a Borromean three-body structure. We discuss and compare four-body, i.e. three-body projectile plus target, reaction model calculations of reaction cross sections for such systems that use the fast adiabatic approximation. These methods are efficient and well-suited for quantitative analyses of reactions of neutron-rich nuclei with light target nuclei at secondary beam energies of $\approx$300 MeV/nucleon, as are now becoming available. We compare the predictions of the adiabatic model of the reaction both without and when including the additional eikonal approximation that has been used extensively. We show that the reaction cross section calculations have only limited sensitivity to the size and structure of $^{22}$C and that the differences arising from use of the eikonal approximation of the reaction mechanism are of a similar magnitude.