Phenomenologycal implication of the topflavour model

Abstract

We study the phenomenologies of the topflavour model in which the third generation fermions undergo a different SU(2) weak interaction from the first two generation fermions. This model shows a characteristic feature, existence of flavour changing neural currents even for the lepton sector. To test this model by low energy data, we use lepton number violating process τ → μμμ, τ → eee and the atomic parity violation (APV) experiment in the $C_s$ atoms. Implications of the model on the Z peak data are studied in terms of the precision variables $\epsilon_i``s$. We find that the LEP data give more stringent constraints on the model parameters than leptonic decay and the APV data and the mass of heavy gauge bosons is bounded from below to be about 1.2 Tev (1.1 Tev) at 90 (95) % C.L. This model predicts non-standard effects for B physics. By the flavour- changing neutral current interactions of this model, the B - $\bar{B}$ mixing amplitudes are substantially affected while it is hard to investigate the effects on rare decays. Violation of the unitarity of the CKM matrix is also discussed. We find that the bound on |$V_{td}$| can be stronger in this model by combining the experimental bound of the B - $\bar{B}$ mixing and the bound from violated unitarity.