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. PACS numbers: 04.50.+h, 04.20.Jb, 11.10.Kk ∗ Electronic address : [email protected] † Electronic address: [email protected]