Unparticle Self-Interactions and Their Collider Implications

Abstract

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 $pp->U->UU->\gamma \gamma \gamma \gamma$, $\gamma \gamma ZZ$, $ZZZZ$, $\gamma \gamma l^{+}{l}^{-}$, $ZZ{l}^{+}{l}^{-}$, 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.

Comments: 12 pages, 5 figures; v2: published version