Speaker
Description
We study extended warped extra-dimensional models in which gravity propagates to a deep infrared brane with warped scale $\Lambda_{IR} \sim \mathcal{O}(\mathrm{MeV})$, leading to a dense KK graviton tower with MeV-scale spacing. We present a DUNE-motivated model realization of the photon portal to this tower. The visible electroweak gauge sector extends to an intermediate GeV brane, and brane-localized kinetic terms are used to control precision-electroweak constraints while preserving an enhanced coupling between KK gravitons and the photon. Primakoff-like production at DUNE then can produce GeV-scale KK gravitons, which then cascade down the tower to the lightest mode. If the radion channel is kinematically closed for the terminal state, the lightest KK graviton becomes long lived and decays visibly to diphotons. In this talk I discuss the resulting rich phenomenology of production, cascade decays, and signals at DUNE, and outline the main theoretical and precision constraints relevant for this extended warped scenario.