ATLAS prospects for New Physics using neutrino-like signatures

Many possible extensions to the Standard Model predict new particles and heavy neutrinos. Standard Model neutrinos are invisible to detectors at colliders but they are indirectly detected using the event Missing Transverse Energy MET. Some of the new stable particles are also invisible to detectors and are detected through their MET. In this paper, we discuss how ATLAS is using the MET~ signatures from standard neutrinos or from new particles to prepare for the analysis of the first fb$^{-1}$ of good data at 14TeV in view of discovering new physics beyond the Standard Model.