Precise measurement of the ντ cross-section would enable a test of lepton universality in neutrino scattering and searches for new physics effects in ντ-nucleon interactions. It also has practical implications for neutrino oscillation experiments. The only practical method to produce a tau neutrino beam is through the decays of Ds mesons, whose production lacks measurement. Eventually, the uncertainties of the accelerator-based tau neutrino measurements is dominated by the uncertainty of the Ds meson production process. The DsTau project studies tau-neutrino production following 400 GeV proton-nucleus interactions at the CERN SPS, aiming at providing fundamental inputs for future ντ measurements. For this purpose, emulsion detectors with a nanometre-precision readout will be used to detect the particular decay topology of the Ds→τ→X double kinks in a few mm range. The project overview, results from the beam tests and the analysis status of the pilot run in 2018 will be presented together with a prospect for the physics run in 2021.
