$A$-dependence of coherent electroproduction of ${\rho }^0$ mesons on nuclei in forward direction

Abstract

This article presents the $A$-dependence of the differential cross section for the coherent electroproduction of vector mesons on nuclei in forward direction, at fixed values of longitudinal momentum transfer $q_L$. It is shown that such cross section has complicated behavior over the atomic mass number $A$ with local minimums and maximums. It is also shown that a ratio of the real to the imaginary parts of the forward coherent amplitude on nuclei ${\alpha }_A=\Re e{f}_A/\Im m{f}_A$ has breaking points at some values of $A$. Comparison of the behaviors of the normalized cross section $(\frac{d\sigma }{d\Omega }{)}_A/(\frac{d\sigma }{d\Omega }{)}_N$ and ${\alpha }_A$ over $A$ shows that the location of minimums of the cross section are very close to the breaking points of ${\alpha }_A$.