Tubular branes in fluxbranes

We describe the construction of new configurations of self-gravitating p-branes with worldvolume geometries of the form R-1,R-p-s x S-s, with 1 less than or equal to s less than or equal to p, i.e., tubular branes. Since such branes are typically unstable against collapse of the sphere, they must be held in equilibrium by a fluxbrane. We present solutions for string loops with non-singular horizons, as well as M5-branes intersecting over such loops. We also construct tubular branes which carry in their worldvolume a dissolved, lower dimensional brane (as in the dielectric effect), or an F-string. However, the connection between these solutions and related configurations that have been studied earlier in the absence of brane self-gravity, is unclear. It is argued that, at least in some instances, the self-gravitating solutions do not appear to be able to reproduce stable configurations of tubular branes. (C) 2001 Elsevier Science B.V All rights reserved.