Phenomenological constraints on extra-dimensional scalars

We examine whether the ATLAS detector has sensitivity to extra-dimensional scalars (as opposed to components of higher-dimensional tensors which look like 4D scalars), in scenarios having the extra-dimensional Planck scale in the TeV range and n ≥ 2 non-warped extra dimensions. Such scalars appear as partners of the graviton in virtually all higher dimensional supersymmetric theories. Using the scalar's lowest dimensional effective couplings to quarks and gluons, we compute the rate for the production of a hard jet together with missing energy. We find a non-trivial range of graviscalar couplings to which ATLAS could be sensitive, with experiments being more sensitive to couplings to gluons than to quarks. Graviscalar emission increases the missing-energy signal by adding to graviton production, and so complicates the inference of the extra-dimensional Planck scale from an observed rate. Because graviscalar differential cross-sections resemble those for gravitons, it is unlikely that these can be experimentally distinguished from one another should a missing-energy signal be observed.