Radius stabilization and anomaly-mediated supersymmetry breaking - art. no. 035008

We analyze in detail a specific 5-dimensional realization of a "brane-unive rse" scenario where the visible and hidden sectors are localized on spatial ly separated 3-branes coupled only by supergravity, with supersymmetry brea king originating in the hidden sector. Although general power counting allo ws order 1/M-Planck(2) contact terms between the two sectors in the 4-dimen sional theory from exchange of supergravity Kaluza-Klein modes, we show tha t they are not present by carefully matching to the 5-dimensional theory. W e also find that the radius modulus corresponding to the size of the compac tified dimension must be stabilized by additional dynamics in order to avoi d runaway behavior after supersymmetry breaking and to understand the commu nication of supersymmetry breaking. We stabilize the radius by adding two p ure Yang-Mills sectors, one in the bulk and the other localized on a brane. Gaugino condensation in the 5-dimensional effective theory generates a sup erpotential that can naturally fix the radius at a sufficiently large value that supersymmetry breaking is communicated dominantly by the recently dis covered mechanism of anomaly mediation. The mass of the radius modulus is l arge compared to m(3/2) The stabilization mechanism requires only parameter s of order one at the fundamental scale, with no fine-tuning except for the cosmological constant.