Scalar Modifications to Gravity from Unparticle Effects May Be Testable

Interest has focused recently on low energy implications of a nontrivial scale invariant sector of an effective field theory with an IR fixed point, manifest in terms of “unparticles” with peculiar properties. If unparticle stuff exists it could couple to the stress tensor and mediate a new “fifth” force (“ungravity”). Under the assumption of strict conformal invariance in the hidden sector down to low energies, we compute the lowest order ungravity correction to the Newtonian gravitational potential and find scale invariant power law corrections of type (R_G/r)^2d_U-1, where d_U is an anomalous unparticle dimension and R_G is a characteristic length scale where the ungravity interactions become significant. It is shown that a discrimination between extra dimension models and ungravity is possible in future improved submillimeter tests of gravity.