γγ→γγas a test of weak scale quantum gravity at the NLC

Recently, it has been proposed that the fundamental scale of quantum gravity can be close to the weak scale if there are large extra dimensions. This proposal has important phenomenological implications for processes at the TeV scale. We study the process $\gamma \overrightarrow{\gamma }\gamma \gamma ,$ assuming an ultraviolet cutoff $M_S\sim 1\hspace{0.5em}\mathrm{TeV}$ for the effective gravity theory. We find that, at the center of mass energies $\sqrt{s}\sim 1\hspace{0.5em}\mathrm{TeV},$ the contribution of gravitationally mediated scattering to the cross section is comparable to that coming from the one-loop Feynman diagrams of the standard model. We thus conclude that the effects of weak scale quantum gravity can be studied at the Next Linear Collider (NLC), in the photon collider mode. Our results suggest that, for typical proposed NLC energies and luminosities, the range $1\hspace{0.5em}\mathrm{TeV}\lesssim M_S\lesssim 10\hspace{0.5em}\mathrm{TeV}$ can be probed.