Search for charged Higgs bosons in e(+)e(-) collisions at root s = 172 GeV

This paper presents results on charged Higgs boson production, based on LEP data collected at root s = 172 GeV, that complement the previous DELPHI results obtained at centre of mass energies up to 161 GeV. The charged Higgs bosons are assumed to be pair produced and to decay either into a quark pair or into tau nu(tau). The three different possible final states are included in the analysis. Data from rings imaging Cherenkov and microvertex detectors are used to identify the quarks as a cs pair, The number of candidates found is compatible with the background expected from standard processes. Combining the results of the present analysis with those of the previous analysis at lower energies, a new lower mass limit for the charged Higgs boson is set at 54.5 Gev/c(2). (C) 1998 Elsevier Science B.V.