Session 01: lessons from 2011

In 2011 LHC had excellent performance in both machine and experiments. In a month the same luminosity as during the full 2010 proton run was delivered, and a factor 16 higher luminosity was produced with Pb ions. The excellent machine performance allowed ATLAS and CMS to make interesting observations in the context of the Higgs' boson search and LHCb found some evidence of CP violation in time-integrated D0 which could open the way for a new physics. Special runs were dedicated to p-p collisions at intermediate energy (1.38 TeV), high β* for roman pots (optics checks, setup and data taking) and p-p luminosity calibration. A problem with the PS septum for proton extraction did not allow to accomplish the p-Pb run. ALICE could profit of collisions between main bunches and spontaneously produced satellites. This opened the way for a successful run with an artificially increased rate of satellites from 1-2 per thousand to 1-2%. Thanks to a smaller β* and higher brightness beams it was possible to improve and speed up the luminosity production: almost 80% of the luminosity was accumulated in the second half of the year. The 2012 run will be mainly devoted to luminosity production