Speaker
Description
During the last years several Dark Sector Models have been proposed in order to address striking astrophysical observations which fail standard intepretations.
In the minimal case a new vector particle, the so called dark photon or U-boson, is introduced, with small coupling with Standard Model particles. Also, the existence of a dark Higgs boson h' is postulated, in analogy with the Standard Model, to give mass to the U-boson through the Spontaneous Symmetry Breaking mechanism.
The experiment KLOE, working on the Dafne e+e- collider in Frascati, searched for the existence of the U-boson in a quite complete way, investigating several different processes and final states:
- in dalitz decays of the Phi meson Phi-> eta U, with U->e+e- and eta-> pi+pi-pi0 and p0p0p0
- in e+e- -> U gamma events, with U decaying to electron, muon and pion pairs
- in the dark Higgsstrahlung process, e+e- -> Uh', U-> mu+mu-, h' invisible.
New results in U to muon and U to pion decays, and their combination, will be available at the time of the ICHEP Conference.
Tight limits on the model parameters have been set at 90%CL. Further improvements are expected in terms of sensitivity and discovery potential with the new KLOE-2 detector working on the improved DAFNE e+e- collider.
