Search for supersymmetry in the photon(s) plus missing energy channels at GeV and 172 GeV

Searches for supersymmetric particles in channels with one or more photons and missing energyhave been performed with data collected by the ALEPHdetector at LEP. The data consistof 11.1 \pb\ at $\sqrt{s} = 161 ~\, \rm GeV$, 1.1 \pb\ at 170 \gev\ and 9.5 \pb\ at 172 GeV. The \eenunu\ cross se ction is measured. The data are in good agreement with predictions based on the Standard Model, and are used to set upper limits on the cross sections for anomalous photon production. These limits are compared to two different SUSY models and used to set limits on the neutralinomass. A limit of 71 \gevsq\ at 95\% C.L. is set on the mass of the lightest neutralin o ($\tau_{\chi_{1}^{0}} \leq $ 3 ns) for the gauge-mediated supersymmetry breakingand LNZ models.