W, Z + Jets production with CMS detector
  We present a study of jet production in association with W and Z bosons in proton-proton collisions at a centre-of-mass energy of 7 TeV using the full 2010 data set collected by CMS corresponding to an integrated luminosity of (35.9 +/- 1.4) inverse picobarn. We report the measurement of ratios s(V + >= n jets)/s(V) and s(V + >= n jets)/s(V + >= (n - 1) jets), where V represents either a W or a Z, s stands for the cross section and n stands for the number of jets. 
Sandro Gonzi (1 and 2) (for the CMS Collaboration) ((1) Universit\`a   degli Studi di Firenze, (2) INFN Sezione di Firenze)
hep-ex