Self-tuning in an outgoing brane wave model - art. no. 086005

We introduce a new brane-world model in which the bulk solution consists of outgoing plane waves. This is an exact solution to string theory with no n aked singularities. The recently discussed self-tuning mechanism to cancel the cosmological constant on a brane is naturally incorporated. We show tha t even if the vacuum energy on the brane changes, e.g. due to a phase trans ition, the brane geometry remains insensitive to the local vacuum energy. W e also consider the static self-tuning branes introduced earlier, and find a solution in which the brane geometry starts to contract when the vacuum e nergy on the brane changes.