ON THE VECTOR MESON DOMINATE HYPOTHESIS AND THE R_A = σ^A_L /σ^A_T VALUE IN ELECTRON-NUCLEUS DEEP INELASTIC SCATTERING

It is argued that the longitudinal part of space-like photon in its Breit frame is unable to transform into vector meson. Starting from this argument and adding a small amount of diquark component into the nucleon structure functions in nuclei, the A dependence of the R_A = σ^A_L /σ^A_T value observed in electron nucleus DIS by the SLAC Group is explained.