gamma gamma ->gamma gamma as a test of weak scale quantum gravity at the NLC - art. no. 084022

Recently, it has been proposed that the fundamental scale of quantum gravit y can be close to the weak scale if there are large extra dimensions. This proposal has important phenomenological implications for processes at the T eV scale. We study the process gamma gamma -->gamma gamma, assuming an ultr aviolet cutoff Ms similar to 1 TeV for the effective gravity theory. We fin d that, at the center of mass energies root s similar to 1 TeV, the contrib ution of gravitationally mediated scattering to the cross section is compar able to that coming from the one-loop Feynman diagrams of the standard mode l. We thus conclude that the effects of weak scale quantum gravity can be s tudied at the Next Linear Collider (NLC), in the photon collider mode. Our results suggest that, for typical proposed NLC energies and luminosities, t he range 1 TeV less than or similar to M-S less than or similar to 10 TeV c an be probed. [S0556-2821(99)06618-7].