The ENUBET Project. A high precision narrow-band neutrino beam

The knowledge of initial flux, energy and flavor of neutrino beams is currently the main limitation for a precise measurement of neutrino cross sections. The ENUBET project is studying a facility based on a narrow band neutrino beam capable of constraining the neutrino fluxes normalization through the monitoring of the associated charged leptons in an instrumented decay tunnel. In particular, the identification of large-angle positrons from $K_{e3}$ decays at single particle level can potentially reduce the $\nu_{e}$ flux uncertainty at the level of 1%.The ENUBET Collaboration presented at EPS-HEP2019 the advances in the design and simulation of the hadron beam line, the performance of positron tagger prototypes tested at CERN beamlines, a full simulation of the positron reconstruction chain and the expected physics reach.