The ENUBET experiment

The knowledge of the initial flux in conventional neutrino beams represents the main limitation for a precision (1%) measurement of νe and νμ cross-sections. The ENUBET ERC project is studying a facility based on a narrow-band 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 Ke3 decays at single-particle level can reduce the νe flux uncertainty at the level of 1%. This setup would allow for an unprecedented measurement of the νe cross-section at the GeV scale. Such an experimental input would be highly beneficial to reduce the budget of systematic uncertainties in the next long baseline oscillation experiments. The ENUBET Collaboration presented at ICNFP 2020 the advances in the design and simulation of the hadron beamline, the optimization and performances of a 20 m long focusing transfer line, the design of an horn-based beamline, the results in terms of particle identification in the decay tunnel, and the final design of the ENUBET demonstrator for the instrumented decay tunnel.