Soft and Hard Diffraction at CMS

The observation of a diffractive signal dominated by the inclusive single diffractive dissociation reaction pp -> pX is presented. The analysis is based on a fraction of the data collected by the CMS experiment in 2010 and corresponds to an integrated luminosity of 10, 0.4 and 20 mub-1 at 0.9, 2.36 and 7 TeV, respectively. Detector level distributions are compared to fully simulated and reconstructed Monte Carlo predictions obtained with the PYTHIA6, PHOJET and PYTHIA8 generators. The observation of the production of W and Z bosons at the LHC in pp collision events with a large rapidity gap is presented. Using data collected by the CMS experiment in 2010, corresponding to an integrated luminosity of 35 pb-1, a detailed study of the event structure and the energy distribution in the forward region of w and Z events is presented. These contain also event samples which are dominated by diffractive interactions