Search for a new light boson in η decays using the WASA detector

Abstract

Some dark matter scenarios predict a light scalar boson that couples to charged leptons. Present experiments do not exclude the existence of a new light (M<1GeV) particle(s) with small coupling to leptons. It can manifest itself in η meson decays with electron-positron pair(s)in the final state. We present preliminary results from the search for η → π0 + (X → e+e−) decay in a total of 5 × 107 η mesons produced in the pp → ppη reaction, a fraction of the data collected in the WASA experiment.