Abstract :
We propose a (generalized) “mass formula” for a fundamental string described as a BPS solution of a D-braneʹs worldvolume. The mass formula is obtained by using the Hamiltonian density on the worldvolume, based on transformation properties required for it. Its validity is confirmed by investigating the cases of point charge solutions of D-branes in a D-8-brane (i.e. curved) background, where the mass of each of the corresponding strings is proportional to the geodesic distance from the D-brane to the point parametrized by the (regularized) value of a transverse scalar field. It is also shown that the mass of the string agrees with the energy defined on the D-braneʹs worldvolume only in the flat background limit, but the agreement does not always hold when the background is curved.
