Phenomenology of vector-meson electroproduction on spinless targets

Advantages of the amplitude method for the vector-meson-production description in respect of the spin-density-matrix-element (SDME) method are discussed. It is shown that for any nonzero amplitudes the angular distribution of final particles is non-negative. The exact formula for $R = \frac{d \sigma_L}{d t}/\frac{d \sigma_T}{d t}$ in terms of the SDMEs for spinless targets and the new approximate formula for nucleons are presented.