Unparticle effects in rare (t -> c g g) decay

Abstract

Rare (t -> c g g) decay can only appear at loop level in the Standard Model (SM), and naturally they are strongly suppressed. These flavor changing decays induced by the mediation of spin-0 and spin-2 unparticles, can appear at tree level in unparticle physics. In this work the virtual effects of unparticle physics in the flavor-changing (t -> c g g) decay is studied. Using the SM result for the branching ratio of the (t -> c g g) decay, the parameter space of d_U and Lambda_U, where the branching ratio of this decay exceeds the one predicted by the SM, is obtained. Measurement of the branching ratio larger than 10^(-9) can give valuable information for establishing unparticle physics.