Search for charged Higgs bosons and measurement of |Vcs| in quark and lepton flavour identified events at LEP2

A search for pair produced charged Higgs bosons was performed on the high energy data collected by DELPHI at LEP2. All three major final states, τντν, csτν and cscs were searched for. The analyses used a combination of event shape variables, di-jet masses and jet flavour tagging. The jet flavours were identified by using life time tagging and particle identification based on the RICH detector complemented by ionisation energy loss measurements. A similar type of jet flavour tagging was also used in extracting the |Vcs| element of the Cabibbo–Kobayashi–Maskawa (CKM) matrix in hadronic decays of the W± boson.