Rare Charm decays in the LHCb experiment

This work describes the first observation of the rare four-body decay of D0 meson to final state composed by one kaon, one pion, and two oppositely charged electrons, investigated for the first time. The search is performed using proton-proton collision data collected by the LHCb experiment during 2016 at a centre-of-mass energy of 13 TeV and an integrated luminosity of 1.6 fb−1. These decays offer a unique opportunity to test physics effects beyond the SM, commonly referred to as NP, in the up quark sector, complementary to similar studies performed in K and B physics.