Search for charged Higgs bosons in $e^+ e^-$ collisions at $\sqrt{s}$ = 189-202 GeV}

A search for pair-produced charged Higgs bosons was performed in the high energy data collected by the DELPHI detector at LEP II at centre-of-mass energies from 189~GeV to 202~GeV\@. The three different final states, $\tau \nu \tau \nu$, $c \bar s \bar c s$ and $c \bar s \tau \nu$ were considered. New methods were applied to reject wrong hadronic jet pairings and for the tau identification, where a discriminator based on tau polarisation and polar angles was used. No excess of data compared to the expected Standard Model processes was observed and the existence of a charged Higgs boson with mass lower than 71.5 GeV/$c^2$ is excluded at the 95\% confidence level.