Quark and gluon spin-2 form factors to two loops in QCD

Abstract

We present two-loop QCD corrections to the quark form factor from the amplitude G ! q q and the gluon form factor from G ! gg in SU(N) gauge theory with n f light flavours. We use d- dimensional regularisation and the results are presented to all orders in e = dThese form factors can be used to obtain next-to-next-to-leading order QCD corrections to hadronic scat- tering processes in large extra-dimension model where Kaluza-Klein graviton modes couple to Standard Model fields. We find that the form factors satisfy Sudakov integro-differential equation and the resulting cusp, collinear and soft anomalous dimensions are identical to those of elec- troweak vector boson and gluon form factors. We establish the universal behaviour of the infrared singularities in accordance with the proposal by Catani.