Clustering structure of nuclei in deep inelastic processes

A clustering aspect is explained for the ⁹Be nucleus in charged-lepton deep inelastic scattering. Nuclear modifications of the structure function F₂ are studied by the ratio R_EMC = F^A₂/F^D₂, where A and D are a nucleus and the deuteron, respectively. In a JLab experiment, an unexpectedly large nuclear modification slope |dR_EMC/dx| was found for ⁹ Be, which could be related to its clustering structure. We investigated a mean conventional part of a nuclear structure function F^A₂ by a convolution description with nucleon momentum distributions calculated by antisymmetrized (or fermionic) molecular dynamics (AMD) and also by a simple shell model. We found that clustering effects are small in the conventional part, so that the JLab result could be associated with an internal nucleon modification or a short-range nuclear correlation which is caused by high densities due to cluster formation