Probing Naked Singularities in Non-supersymmetric String Vacua
  We present a detailed analysis of non-supersymmetric spacetime varying string vacua which can lead to an exponential hierarchy between the electroweak and the gravitational scales. In particular, we identify a limit in which these vacua can be interpreted as supersymmetric vacua of F-theory. Furthermore, we study the properties of these solutions as seen by $D7$-brane probes and establish a non-supersymmetric analogue of the enhancon mechanism. 
P. Berglund, T. Hubsch and D. Minic