OSQAR Annual Report 2014

In 2014, the OSQAR Light Shining through Wall (LSW) experiment has been run very efficiently with both spare LHC dipoles re-commissioned on cryogenic benches at CERN-SM18. To improve the sensitivity, a new 18 W CW laser working at 532 nm and a new CCD detector have been installed, aligned and operated. Preliminary treatments and analysis of data recorded in 2014 provide new exclusion limits for the search of scalar and pseudo-scalar light particle that go much beyond the present reference ones obtained by the ALPS collaboration and slightly improved in 2013 by OSQAR. Final and detailed analyses are ongoing. To further improve the sensitivity of the OSQAR-LSW experiment, the developments and tests of Fabry-Perot cavities have been pursued. For 2015, the OSQAR collaboration will focus on a new proposal for the search of chameleons, a hypothetical scalar particle postulated as a dark energy candidate, which can couple strongly or weakly to matter as a function of the environment. The new required experimental set-up has been successfully tested and validated in 2014.