Boundary states of D-branes and dy-strings Original Research Article

Polchinskiʹs recent construction of Dirichlet branes of R-R charges, together with Wittenʹs mechanism for forming bound states of both NS-NS charges and R-R charges, provides a rigorous method to treat these dy-branes. We construct the massless sector of boundary states of D-branes, as well as of dy-strings of charge (p, 1). As a consequence, the string tension formula predicted by duality in the type IIB theory is obtained.