Heavy particle electroweak loop effects in extra-dimensional models with bulk neutrinos

One way to detect the presence of new particles in theories beyond the standard model is through their contribution to electroweak loop effects. We comment on the importance of a consistent inclusion of their mixing angles to ensure that the physical requirement of heavy particle decoupling is fulfilled. We illustrate our points by a detailed discussion of the lepton flavor changing effect μ→eγ, investigated recently by Kitano, in the Randall–Sundrum model. Our remarks are equally applicable to models with large compactified dimensions where bulk neutrinos are introduced to account for the observed neutrino oscillations.