The COMPASS  Collaboration comprises about  230   physicists and the experiment   is located   in  EHN2 (888) in  the North Area. COMPASS measured in  2012   the  electric  and  magnetic  polarizability   of  the pion  and  collect  for the first  time  data  on  the  kaon  polarizability.  These  polarizabilitites  are   fundamental  properties of   pions/kaons  and can be calculated with high  precision  in  Chiral   Perturbation  Theory –  a   low energy expansion of   QCD.