Collective effects in the nuclear interactions of charmonium at low energy

In view of the recent interest in the problem of the nuclear interactions of charmonium, we consider the role of higher order multiple scattering and nucleon-nucleon correlation effects in charmonium-4He interaction at zero energy. We find a remarkably large enhancement of the calculated low-energy cross section over the standard coherent impulse approximation. This is a consequence of large collectivity induced by the higher order effects in the multiple scattering expansion which appear to play a crucial role for the case of a real and negative (corresponding to attraction) elementary scattering length.