%0 Journal Article
%T Search for the U-boson in the process $e^ +e^- \to ¦Ì^+ ¦Ì^- ¦Ã, \,\, U \to ¦Ì^+¦Ì^-$ with the KLOE detector
%A F. Curciarello
%J Physics
%D 2015
%I arXiv
%R 10.5506/APhysPolB.46.39
%X We present a search for a new light vector boson, carrier of a "dark force" between WIMPs, with the KLOE detector at \DA$\Phi$NE. We analyzed $e^+ e^- \to \mu^+ \mu^- \gamma$ ISR events corresponding to an integrated luminosity of $239$ pb$^{-1}$ to find evidence for the $e^+ e^- \to U\gamma ,\,\, U\to\mu^+\mu^-$ process. We found no $U$ vector boson signal and set a 90% CL upper limit on the ratio of the U boson and photon coupling constants between 1.6$\times10^{-5}$ to 8.6$\times10^{-7}$ in the mass region $520<M_{\rm U}<980$ MeV. A projection of the KLOE sensitivity for the $\mu\mu\gamma$ and $\pi\pi\gamma$ channels at full statistics and extended muon acceptance is also presented.
%U http://arxiv.org/abs/1501.04424v1