Dynamical model of coherent pion production in neutrino-nucleus scattering

We study coherent pion production in neutrino-nucleus scattering in the energy region relevant to neutrino oscillation experiments of current interest. Our approach is based on the combined use of the Sato-Lee model of electroweak pion production on a nucleon and the Delta-hole model of pion-nucleus reactions. Thus we develop a model that describes pion-nucleus scattering and electroweak coherent pion production in a unified manner. Numerical calculations are carried out for the case of the C-12 target. All the free parameters in our model are fixed by fitting to both total and elastic differential cross sections for pi-C-12 scattering. Then we demonstrate the reliability of our approach by comparing our prediction for coherent pion photoproductions with the data. Finally, we calculate total and differential cross sections for neutrino-induced coherent pion production, and some of the results are compared with recent data from K2K, SciBooNE, and MiniBooNE. We also study the effect of nonlocality of Delta propagation in the nucleus and compare the elementary amplitudes used in different microscopic calculations.