On singularities of spherically symmetric backgrounds in string theory

Abstract

We suggest that for singular rotationally invariant closed string backgrounds which need sources for their support at the origin (in particular, for special plane waves and fundamental strings) certain `trivial' \a'-corrections (which are usually ignored since in the absence of sources they can be eliminated by a field redefinition) may play an important role eliminating the singularities in the exact solutions. These corrections effectively regularize the source delta-function at the \a'-scale. We demonstrate that similar smearing of the singularity of the leading-order point-source solution indeed takes place in the open string theory.