Flavors and phases in unparticle physics

Inspired by the recent Georgi's unparticle proposal, we study the flavor structures of the Standard Model (SM) particles when they couple to unparticles. At a very high energy scale, we introduce BZ charges for the SM particles, which are universal for each generation and allow BZ fields to distinguish flavor generations. At the Lambda(u) scale, BZ operators and charges are matched onto unparticle operators and charges, respectively. In this scenario, we find that tree flavor changing neutral currents (FCNCs) can be induced by the rediagonalizations of the SM fermions. As an illustration, we employ the Fritzsch ansatz to the SM fermion mass matrices and we find that the FCNC effects could be simplified to be associated with the mass ratios denoted by root m(i)m(j)/m(3)(2), where m(3) is the mass of the heaviest particle in each type of fermion generations and i, j are the flavor indices. In addition, we show that there is no new CP violating phase for FCNCs in down type quarks beside the unique one in the CKM matrix. We use (B) over bar (q) -> l(+) l(-) as examples to display the new FCNC effects. In particular, we demonstrate that the direct CP asymmetries in the decays can be O(10%) due to the peculiar CP conserving phase in the unparticle propagator. (C) 2008 Elsevier B.V. All rights reserved.