What is the , or irreducible background to the light Higgs-boson searches at LHC? B.P. Kersevan and E. Richter-Wąs Eur. Phys. J. C, 25 3 (2002) 379-389 Published online: 30 August 2002 DOI: 10.1007/s10052-002-1001-3