  A search for charginos and neutralinos, predicted by supersymmetric theories,
has been performed using a data sample of 57 pb-1 at centre-of-mass energies of
181-184 GeV taken with the OPAL detector at LEP. No evidence for chargino or
neutralino production has been found. Upper limits on chargino and neutralino
pair production cross-sections are obtained as a function of the chargino mass,
the lightest neutralino mass, and the second lightest neutralino mass. For
large chargino masses the limits have been improved with respect to the
previous analyses at lower centre-of-mass energies. Exclusion regions at 95%
confidence level of parameters of the Constrained Minimal Supersymmetric
Standard Model are determined for the case of a large universal scalar mass,
m_0, implying heavy scalar fermions, and for the case of a small m_0 resulting
in light scalar fermions and giving the worst-case limits. Within this
framework and for the lightest chargino-neutralino mass difference greater than
5 GeV the 95% C.L. lower limits on the lightest chargino mass for m_0 = 500 GeV
are 90.0 and 90.2 GeV for tan(beta) = 1.5 and 35 respectively. These limits for
all m_0 (the worst-case) are 69.1 and 65.2 GeV for tan(beta) = 1.5 and 35
respectively. Exclusion regions are also presented for neutralino masses,
including an absolute lower limit at 95% C.L. for the mass of the lightest
neutralino of 30.1 GeV for m_0 = 500 GeV (24.2 GeV for all m_0), with
implications for experimental searches for the lightest neutralino as a dark
matter candidate.
