Bounds on curved domain walls in 5d gravity

Abstract

We discuss maximally symmetric curved deformations of the flat domain wall solutions of five-dimensional dilaton gravity that appeared in a recent approach to the cosmological constant problem. By analyzing the bulk field configurations and the boundary conditions at a four-dimensional maximally symmetric curved domain wall, we obtain constraints on such solutions. For a special dilaton coupling to the brane tension that appeared in recent works, we find no curved deformations, confirming and extending slightly a result of Arkani-Hamed et al which was argued using a $Z_2$-symmetry of the solution. For more general dilaton-dependent brane tension, we find that the curvature is bounded by the Kaluza-Klein scale in the fifth dimension.

9 pages, harvmac big. Version 2: Significant error in quantitative bounds corrected; bounds are not numerically smaller than Standard Model physics without further assumptions about the VEV of the dilaton. However, qualitative bound on curvature scale by bulk Kaluza-Klein scale unchanged Version 3: Minor changes