The SOX experiment hunts the sterile neutrino

The SOX (Short distance neutrino Oscillations with BoreXino) experiment aims to perform a resolutive measurement for testing the longstanding hypotesis of a sterile neutrino in the eV$^2$ mass scale. A very intense and well calibrated $^{144}Ce-^{144}Pr$ antineutrino source will be placed under the large size and very low background Borexino detector at Laboratori Nazionali del Gran Sasso in Italy. Borexino demonstrated a such energy and position resolution that the disappearance experiment can be performed and the short distance oscillations might be directly observed. In this paper an overview of the key elements of the experiment is given and the expected sensitivity to determine the sterile neutrino mass is shown.