Studies of identified hadrons in qq̄ events at LEPI, in W+W− and qq̄ events at LEPII and search for stable and long-lived heavy charged particles

The use of RICH detectors allows the identification of charged pions, kaons and protons, covering the full momentum range 0.7≤p≤Ebeam/c. The π±, K± and p(p̄) normalised production rates, their differential cross-sections, multiplicities and the ξp distributions are measured for three event samples, i.e. Z0→qq̄, Z0→bb̄ and Z0→uū, dd̄, ss̄, selected from ∼14 00 000 Z0 decays collected by DELPHI in 1994. This study has been extended to high-energy qq̄ events at LEPII. New heavy particles from 2 GeV/c2 to the kinematic limit at LEPII have been searched using the RICH detectors.