Universal pattern in (e, e′ p) at large missing momenta: quasi-deuteron or diffractive final state interactions?

The intrinsic single particle momentum distributions in nuclei are supposed to show a universal behavior at large momenta, dominated by short-range correlated pairs, or quasi-deuterons. We discuss whether the quasi-deuteron universality survives the final state interaction effects, which are present in the missing momentum spectra measured in A(e, e′ p) experiments at GeV energies. We demonstrate that in the observed missing momentum spectra an approximate universality is present, but originating from the universal pattern of diffractive final state interactions of the struck proton independent of the target nucleus.