Deformation effects on reaction observables of beryllium nuclei from ab initio densities

We combine three-dimensional intrinsic densities from ab initio nuclear lattice effective field theory with a deformed Glauber model to study high-energy reactions of {7-12}Be. To connect the correlated many-body configurations to the core-plus-neutron reaction formalism without imposing a single-particle orbital, we introduce a configuration-resolved prescription that identifies the spatially outermost valence neutron after the two-cluster decomposition. For Be projectiles on 12C and 9Be targets at 790 MeV/A, explicit orientation averaging lowers the calculated reaction cross section of 11Be by up to approximately 50 mb relative to a calculation with the spherically averaged density. The deformed calculation reproduces the pronounced increase from 10Be to the established one-neutron halo nucleus 11Be for both targets. We further calculate the momentum distribution of the fragments after the one-neutron removal reaction of 11Be + 9Be , finding good agreement in shape with the measurement at 63 MeV/A and providing a prediction at 790 MeV/A. These results quantify how intrinsic deformation and weak binding are transmitted from microscopic many-body densities to reaction observables.