Limits on the masses of supersymmetric particles at root s=189 GeV

Searches for charginos, neutralinos and sleptons at LEP2 centre-of-mass energies from 130 GeV to 189 GeV have been used to set lower limits on the mass of the Lightest Supersymmetric Particle and other supersymmetric particles within the MSSM framework. R-parity conservation has been assumed. The lightest neutralino was found to be heavier than 32.3 GeV/c^2 independent of the m_0 value. The lightest chargino, the second-to-lightest neutralino, the next-to-heaviest neutralino, the heaviest neutralino, the sneutrino and the right-handed selectron were found to be heavier than 62.4 GeV/c^2, 62.4 GeV/c^2, 99.9 GeV/c^2, 116.0 GeV/c^2, 61.0 GeV/c^2, and 87.0 GeV/c^2, respectively. These limits do not depend on m_0 or M_2 and are valid for 1 \leq tan(beta) \leq 40, in the mu region where the lightest neutralino is the LSP. If the sneutrino is heavier than the chargino the lightest neutralino has to be heavier than 32.4 GeV/c^2. The effects of mixings in the third family of sfermions on these limits are discussed. The confidence level of all limits given is 95%.