  We discuss the collider phenomenology of Universal Extra Dimension models
with gravity mediated decays. We concentrate on diphoton associated with large
missing transverse energy signature. At the collider, level-1 Kaluza-Klein (KK)
particles are produced in pairs due to the conservation of KK-parity.
Subsequently, KK-particles decay via cascades involving lighter KK-particles
until reaching the lightest KK-particle (LKP). Finally, gravity induced decay
of the LKP into photons gives rise to the diphoton signature. The search for
diphoton events with large missing transverse energy was recently communicated
by the ATLAS collaboration for 7 TeV center-of-mass energy and 3.1 inverse
femtobarn integrated luminosity of the Large Hadron Collider. Above the
Standard Model background prediction, no excess of such events was reported. We
translate the absence of any excess of the diphoton events to constrain the
model parameters, namely, the radius of compactification (R) and the
fundamental Planck mass ($M_D$).
