of the signal when only $s$-channel diagrams are considered, which would be the case if we were to study processes like $e^+ e^- \to \mu^+ \mu^- G_n$ or $e^+ e^- \to \tau^+ \tau^- G_n$. Comparison with the signal of interest makes it obvious that there is a substantial contribution to the Bhabha scattering signal from the $t$-channel, which makes it more viable as a signal of ADD gravity than the other two. In fact, the emission of a high-energy graviton (corresponding to large missing invariant mass) reduces the energy of the underlying Bhabha scattering process, causing a large enhancement due to the $Z$-pole. This is the reason why the signal for large $M_{\rm miss}$ is completely dominated by the $s$-channel contribution. At the same time, when the graviton is relatively soft, the $s$-channel diagrams are strongly suppressed, but the $t$-channel contributions are not; as a result the signal is dominated by the $t$-channel contribution for low $M_{\rm miss}$. We can therefore obtain a clear separation of signal from background by imposing a cut $$M_{\rm miss} > 350 ~(450) ~{\rm GeV~~for}~\sqrt{s} = 500 ~{\rm GeV}~( 1 ~{\rm T
eV})$$ These choices are optimal, after taking into account the fact that the 