One-loop gg->bb(bar) effects in the main irreducible background to exclusive H->bb(bar) production at the LHC

Understand

We calculate the amplitude of gg->bb(bar) production for the colour singlet, J_z=0 di-gluon state at O(\alpha_S^2) order.

• We consider the cancellation, and a realistic cutoff, of the infrared divergent terms.
• We show that the one-loop radiative QCD contributions effectively reduce the Born level result for the central exclusive bb(bar) cross section at the LHC.
• This process is essentially the only irreducible QCD background to the exclusive H->bb(bar) signal.