Search for low mass dark gauge bosons at KLOE

Abstract

The existence of a light dark force mediator has been tested with the KLOE detector at DAΦNE. This particle, the so called dark photon U, has been searched for in three different processes and four different final states: a) Φ → ηU, with U → e+e−, η → π+π−π0 and η → π0π0π0; b) e+e− → Uγ with U → μ+μ−; c) e+e− → Uh' (dark Higgsstrahlung), U → μ+μ−, where h' is a Higgs-like particle responsible for the breaking of the hidden symmetry.We did not find any evidence of the processes above and set upper limits on the parameters of the model, for different MU (and Mh') mass ranges, depending on the considered final state.