  In the Randall-Sundrum (RS) compactification, the gap between two branes is
stabilized by the vacuum expectation value of a scalar field called {\it
radion}, $\phi$. This radion behaves like a weak interaction singlet scalar
field, coupling to matter through the trace of the energy momentum tensor. We
find that it can induce a sizable correction to the weak mixing angle if the
vacuum expectation value and the mass of the radion is around TeV. We also
comment on the contribution to the $K_L-K_S$ mass difference and to
$(g-2)_\mu$.
