YSF Dark Matter produced in association with top quark pair

LHC Search for Dark Matter produced in association with top quark pair is presented. The search is performed using 19.7 fb-1 of pp collisions recorded at a center of mass energy of 8 TeV with the CMS detector at LHC. The signature investigated is top quark pairs in semi-leptonic final state plus missing transverse energy. This work focuses in particular on Dark Matter production through scalar interaction where a proportionality to the quark mass is expected. This can enhance the discovery potential of the LHC under this assumption.