Some Aspects of Massive World-Brane Dynamics

We study the internal dynamics of Ramond-Ramond solitons excited far from the BPS limit by leading Regge trajectory open strings. The simplest world volume process for such strings is splitting into two smaller pieces, and we calculate the corresponding decay rates. Compared to the conventional open superstring, the splitting of states polarized parallel to the brane is suppressed by powers of logarithms of the energy. The rate for states polarized transverse to the brane {\em decreases} with increasing energy. We also calculate the static force between a D-brane excited by a massive open string and an unexcited D-brane parallel to it. The result shows that transversely polarized massive open strings endow D-branes with a size of order the string scale.