Axion production from gravitons off interacting 0-branes Original Research Article

We study axion-graviton scattering from a system of two D0-branes in a Type II superstring theory, a process which does not occur on a single brane. The two D0-branes interact via the exchange of closed string states which form a cylinder joining them. By compactifying on the Z3 orbifold we find a non-vanishing amplitude coming from the odd spin structure sector, thus from the exchanged RR states. We compute, in particular, the leading term of the amplitude at large distance from the branes, which corresponds to taking a field theory limit. This seems to suggest that the process takes place through the coupling of an axion to the RR states exchanged between the 0-branes.