We recommend an expansion in the existing program of determining the neutrino reaction cross sections required for the understanding of solar and atmospheric neutrino physics and the neutrino astronomy of astrophysical and cosmological sources.

In response to this growing demand, a four-week program has been devised toward understanding in greater detail the theoretical and experimental issues associated with neutrino response functions. The program hopes to provide a forum by which experts from theoretical, phenomenological, and experimental backgrounds can exchange ideas. Some of the specific topics that are to be addressed include: generalized scaling models that map electron response functions to neutrinos; shell-model and RPA comparisons of low energy neutrino cross-sections, transitions of quasi-elastic to resonance production in neutrino responses, nuclear shadowing effects, and related topics.

The structure of the four-week session will consist of an initial week where experimentalists could review the status of the models and event generators currently employed, followed by a two-week dialog among the theorists aimed at identifying practical steps that could be taken now to improve the reliability of the nuclear response modeling. The final week will culminate in a summary paper that presents a series of recommendations to the community. An important component could be validation: predictions that will be testable in controlled experiments with the NuMI beam and elsewhere. The program will start on July 31st and continue until August 25th, 2006.