Using BDT method for the charm events selection in the DsTau experiment

DsTau (NA65) at the CERN-SPS is a recently approved experiment, which aims to study the tau neutrino production in proton-nuclei interaction. The main source of tau neutrinos is the decay of Ds mesons, namely Ds → τντ and then τ → ντX. There is almost no data on the differential production cross section of Ds in proton-nucleus interactions, which leads to a large uncertainty of tau neutrino interaction cross section measurements preventing a precise test of Lepton Flavour Universality in neutrino scattering. DsTau addresses this issue and will provide essential inputs for future tau neutrino experiments. A large amount of charmed particles decay events (~105) is expected to be detected as well, providing a possibility for interesting by-product studies, in particular a search for intrinsic charm in a proton. The experimental method is based on a use of high resolution emulsion detectors for effective registration of events with short lived particle decays. Here I present the motivation of the study, details of the experimental technique and the possible improvement that BDT method can provide for the signal/background events separation.