Study of tau-neutrino production at the CERN SPS (CERN-NA65)

The tau neutrino is one of the least studied particle in the Standard Model. Current tau neutrinonucleon cross section measurement suffer large ∼ 30% statistical and ∼ 50% systematic uncertainties. In near future statistical uncertainty will be reduced to a few % by the SHiP experiment, or by the experiments such as SHiP. DsTau (NA65) experiment at CERN aims to reduce the systematic uncertainty on tau neutrino-nucleon cross section through investigating a precise measurement on tau neutrino production, Ds → τ +ντ differential production cross section with tungsten target. The uncertainty of the tau neutrino flux will be reduced to 10 % from 50%. Collaboration will collect 2.3×108 proton interactions with tungsten target and study about 105 charm associated interactions. A pilot run was performed in 2018 Aug and collecting about a tenth of final statistics to perform full analysis chain. Here the analysis stream and the analysis status of 2018 Aug pilot run will be described.