Braneworlds in six dimensions: new models with bulk scalars

Six-dimensional bulk spacetimes with 3- and 4-branes are constructed using certain non-conventional bulk scalars as sources. In particular, we investigate the consequences of having the phantom ( negative kinetic energy) and the Brans-Dicke scalar in the bulk while obtaining such solutions. We find geometries with 4-branes with a compact on-brane dimension ( hybrid compactification) which may be assumed to be small in order to realize a 3-brane world. On the other hand, we also construct, with similar sources, bulk spacetimes where a 3-brane is located at a conical singularity. Furthermore, we investigate the issue of localization of matter fields (scalar, fermion, graviton, vector) on these 3- and 4-branes and conclude with comments on our six-dimensional models.