  Results are presented from a search for new physics in the final state
containing a photon and missing transverse energy. The data corresponds to an
integrated luminosity of 5.0 fb$^{-1}$ collected in pp collisions at
$\sqrt{s}$= 7 TeV by the CMS experiment. The observed event yield agrees with
standard model expectations. Using models for the production of dark matter
particles($\chi$), we set 90$% confidence level (C.L.) upper limits of
13.6-15.4 fb on $\chi$ production in the $\gamma$+ $\met$ state. These provide
the most sensitive upper limits for spin-dependent $\chi$-nucleon scattering
for \c{hi} masses between 1 and 100 GeV. For spin dependent contributions, the
present limits are extended to M($\chi$) $<$ 3.5 GeV. For ADD models with 3-6
large extra dimensions, our data exclude extra-dimensional Planck scales
between 1.64 and 1.73 TeV at 95% C.L.
