Development of a shell for calculating the sensitivity of accelerator experiments in GNA based on the DUNE experiment

The current paper is dedicated to the modeling of accelerator neutrino oscillation experiments using GNA software for investigating the sensitivities to the neutrino oscillation parameters. A unified shell based on an input configuration file was created. It can produce expected event rate spectra after neutrino oscillations and can calculate sensitivities to neutrino mass hierarchy, CP-phase and θ23 value. The NOvA experiment collected data since 2014 and a planned widescale experiment DUNE were chosen for sensitivity calculations. Event rates obtained in GNA were compared to official Monte-Carlo modeling of NOvA and DUNE collaborations. It was shown based on the sensitivities that NOvA rejects the inverted mass hierarchy for maximal CP-violation (δCP = −π/2) at a significance level above 5σ with 36 × 10^20 POT for the neutrino regime and 36 × 10^20 РОТ for the antineutrino regime exposure. It is shown that DUNE can determine the neutrino mass hierarchy for any possible δ CP phase values at 5σ significance level with an exposure of 1.1 × 10^21 POT/year for 2-3 years according the running staged plan. The DUNE sensitivity at 3σ for the CP-violation hypothesis is achieved for 50% of the values from a δCP range for 7 years of exposure. Based on the analysis of the Asimov data, the sensitivity of NOvA and DUNE to the rejection of the maximum value of mixing angle θ23 was obtained.