Soft Tracks - A probe for New Physics searches at the LHC

In this talk, we will introduce a new variable ξ, namely the number of tracks associated with the primary vertex, which is not parts of the reconstructed objects such as jets/isolated leptons etc in the context of new physics searches in the channel monojet + missing transverse momentum (MET). In models such as in compressed supersymmetry, events are often characterized by a rather large number of soft partons from the cascade decays, none of which result in reconstructed objects. We find that ξ, binned in PT, can discriminate these new physics events from events due to Z+jets background. We also find that the information contained in soft tracks is largely uncorrelated with traditional variables and, therefore, a MultiVariate analysis combining these variables help to increase the discovery potential by more than 200% (depending on the spectra, of course). Pileup robustness of this variable will also be discussed at the end.