Abstract
The spin response of the (gamma) over right arrow(d) over right arrow -> pi(0)d d. p0d reaction near threshold is investigated. Our formalism based on the impulse approximation, uses the realistic Bonn NN potential (full model) for the deuteron wave function and the unitary isobar MAID-2007 model for the elementary gamma N -> pi N amplitude. We present the first results for the double polarized differential and total cross sections for parallel and antiparallel helicity states, the deuteron spin asymmetry, the helicity E-asymmetry, the deuteron GDH integral, and the double spin asymmetries of the total cross section in the near-threshold region. Sensitivity of the estimated results to the D-wave effect of the deuteron wave function for a realistic NN potential is studied. We find an insignificant sensitivity ofmost of the estimated observables to the D-wave component. A noticeable role is obtained only in the double polarized differential cross section with antiparallel spins of photon and deuteron d sigma(A)/d Omega(pi) close to the threshold energy at forward and backward pion angles as well as in the double spin asymmetry of the total cross section sigma(T) over tilde (20) at relatively large photon energies. Thus, we compare results for these two observables using various NN potential models with different D-state probabilities, and a noticeable influence is found.