Determining the relative size of the CP-even and CP-odd Higgs boson couplings to a fermion at the LHC

We demonstrate that the relative size of the CP-even and CP-odd couplings o f a Higgs boson to rr can be determined at the LHC at a level that is very useful in discriminating between models, provided that a Higgs signal can b e observed at a reasonable S/root B level in the trh (with h --> gamma gamm a or b (b) over bar) channels. In particular, the CP-even nature of a SM-li ke Higgs boson's coupling to ti can be confirmed with very substantial stat istical significance using the t (t) over bar h (h --> gamma gamma) product ion/decay mode. (C) 1998 Elsevier Science B.V. All rights reserved.