Phenomenological Implications of the Topflavor Model

We explore phenomenologies of the topflavour model for the LEP experiment at $m_{_Z}$ scale and the atomic parity violation (APV) experiment in the $C_s$ atoms at low energies. 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 the APV data.Comment: 23 pages (including 5 .eps figs), ReVTeX, the 1st revised version, to appear in Phys. Lett.