Unparticle self-interactions and their collider implications

In unparticle physics, operators of the conformal sector have self-interactions, and these are unsuppressed for strong coupling. The 3-point interactions are completely determined by conformal symmetry, up to a constant. We do not know of any theoretical upper bounds on this constant. Imposing current experimental constraints, we find that these interactions mediate spectacular collider signals, such as pp{yields}U{yields}UU{yields}{gamma}{gamma}{gamma}{gamma}, {gamma}{gamma}ZZ, ZZZZ, {gamma}{gamma}l{sup +}l{sup -}, ZZl{sup +}l{sup -}, and 4l, with cross sections of picobarns or larger at the large hadron collider. Self-interactions may therefore provide the leading discovery prospects for unparticle physics.