Seacrh for dark matter and large extra dimensions in monojet events in pp collisions at ?s=7 tev

A search has been made for events containing an energetic jet and an imbalance intransverse momentum using a data sample of pp collisions at a center-of-mass energyof 7 TeV. This signature is common to both dark matter and extra dimensionsmodels. The data were collected by the CMS detector at the LHC and correspond toan integrated luminosity of 5.0 fb?1 . The number of observed events is consistentwith the standard model expectation. Constraints on the dark matter-nucleon scatteringcross sections are determined for both spin-independent and spin-dependentinteraction models. For the spin-independent model, these are the most constraininglimits for a dark matter particle with mass below 3.5 GeV/c2, a region unexploredby direct detection experiments. For the spin-dependent model, these are the moststringent constraints over the 0.1?200 GeV/c2 mass range. The constraints on theArkani-Hamed, Dimopoulos, and Dvali (ADD) model parameter MD determinedas a function of the number of extra dimensions are also an improvement over theprevious results.Key Words: Dark Matter, Extra Dimension, ADD Model, LHC, CMS, Mono-Jet.I