Limits on low scale gravity from e+e−→ W+W−, ZZ and γγ

Abstract

It has been proposed recently that the scale of quantum gravity (“the string scale”) can be M S ∼few TeV with n≥2 extra dimensions of size R≲mm so that, at distances greater than R, Newtonian gravity with M Pl∼10 18 GeV is reproduced if M Pl 2∼ R n M S n+2 . Exchange of virtual gravitons in this theory generates higher-dimensional operators involving SM fields, suppressed by powers of M S . We discuss constraints on this scenario from the contribution of these operators to the processes e + e −→ W + W −, ZZ, γγ. We find that LEP2 can place a limit M S ≈1 TeV from e + e −→ W + W −, ZZ, γγ.