  The elastic backward proton-deuteron scattering is analyzed within a
covariant approach based on the invariant expansion of the reaction amplitude.
The relativistic invariant equations for all the polarization observables are
presented. Within the impulse approximation the relation of the tensor
analyzing power $T_{20}$ and the polarization transfer $\kappa_0$ to $P$-wave
components of the deuteron wave function is found. The comparison of the
theoretical calculations with experimental data is presented. An experimental
verification of the reaction mechanism is suggested by constructing some
combinations of different observables.
