Constraints on heavy Z' couplings from ΔS=2 B--->K-K-π+ decay

The heavy Z' boson with family nonuniversal couplings can introduce flavor changing effects. Constraints on nondiagonal Z' couplings coming from the μ-e conversion in a muonic atom, K⁰-Kbar⁰ and B-Bbar mixing, ɛ and ɛ'/ɛ CP-violating coefficients have been already established. By using the OPAL upper bound of the branching ratio for the B^--->K^-K^-π⁺ decay, we indicate additional constraints on the Z' couplings. We comment also on the constraints of Z' couplings coming from the b-->ddsbar transition. The constraint obtained here from the upper bound of the B^--->K^-K^-π⁺ decay involves a different combination of couplings than those previously presented, but is much weaker.