The footprint of E7(7) in amplitudes of N = 8 supergravity

Abstract

We study the low energy theorems associated with the non-linearly realized continuous E 7(7)() symmetry of the on-shell = 8 supergravity. For Nambu-Goldstone bosons we evaluate the one-soft-scalar-boson emission amplitudes by computing the E 7(7) current matrix element on the one-particle external lines. We use the explicit form of the conserved E 7(7) Noether current and prove that all such matrix elements vanish in the soft momentum limit, assuming the SU(8) symmetry of the S-matrix. This implies that all tree amplitudes vanish in the one-soft-boson limit. We also discuss the implications of unbroken E 7(7)() symmetry for higher-order amplitudes.© 2009 SISSA.