Direct Extraction of Alignment Moments from Inelastic Scattering Images

We present a novel means of analyzing velocity-map images of angular momentum polarization in inelastic scattering. In this approach, linear combinations of angular distributions obtained by integrating select regions of images for two probe laser polarizations directly yield the alignment-free differential cross sections and the differential alignment moments. No fitting is needed in the analysis. The method relies on the fact that the angular distribution for out-of-plane scattering is encoded in the distribution along the relative velocity vector, and this may be recovered quantitatively owing to the redundancy of the in-plane and out-of-plane scattering for the horizontal polarization case.