The Matrix Element Method within CMS

The Matrix Element Method (MEM) is unique among the analysis methods used in experimental particle physics because of the direct link it establishes between theory and event reconstruction. This method was used to provide the most accurate measurement of the top mass at the Tevatron and since then it was used in the discovery of electroweak production of single top quarks. The method can in principle be used for any measurement, with a significant gain compared to cut-based analysis techniques for processes involving intermediate resonances. Within CMS, this method is used in several analysis: to test different spin hypothesis for the newly discovered boson (MELA), as a way to compute the main background for the Higgs production in association with a top quark pair, as it will be discussed in this contribution. The advantages and limitations of this method are also be highlighted, and the latest results presented.