Search for Heavy Neutrinos Using T2K Near Detector ND280

The presented analysis aims at study of heavy neutrinos \((N)\) with masses \(m_{N}<493\text{ MeV/}c^{2}\). These particles can be produced in \(K^{\pm}\) and \(\pi^{\pm}\) decays in the standard neutrino beam and then they subsequently decay in T2K’s near detector ND280. Considered heavy neutrino two- and three-body decay modes are \(N\rightarrow l^{\pm}_{\alpha}\pi^{\mp}\), \(N\rightarrow l^{+}_{\alpha}l^{-}_{\beta}\nu(\overline{\nu})\), where \((\alpha,\beta=e,\mu)\). Search for these events is performed in Time Projection Chambers of ND280 in order to significantly reduce background from neutrino interactions. Usage of new tracking method in TPC among other reconstruction improvements, updated neutrino interaction model and additional statistics will allow to improve experiment sensitivity. Signal selection efficiencies and preliminary systematic uncertainties are shown.