We introduce DarkNews, a lightweight Python-based Monte-Carlo generator for
beyond-the-Standard-Model neutrino-nucleus scattering. The generator handles
the production and decay of heavy neutral leptons via additional vector or
scalar mediators, as well as through transition magnetic moments. DarkNews
samples pre-computed neutrino-nucleus upscattering cross sections and heavy
neutrino decay rates to produce dilepton and single-photon events in
accelerator neutrino experiments. We present two case studies with differential
distributions for models that can explain the MiniBooNE excess. The aim of this
code is to aid the neutrino theory and experimental communities in performing
searches and sensitivity studies for new particles produced in neutrino
upscattering.Comment: 18 pages, 6 tables, 8 figure