Speaker
Description
The analysis presented in this work aims at the study of heavy neutrinos (N) with masses $< 493\,~\text{MeV/c}^2$ produced in charged kaon and pion decays and subsequently decaying in the T2K off-axis near detector ND280. Two- and three-body decay modes are considered:
$N \rightarrow l_{\alpha}^{\pm} \pi^{\mp}, \ N \rightarrow l_{\alpha}^{+} l_{\beta}^{-} \nu (\bar{\nu}),~\text{where (}\alpha, \beta = e, \mu)$
Time Projection Chambers (TPCs) volume is used to reduce background from neutrino interactions. The T2K data accumulated in years $2010-2018$ will be used. First estimations of signal selection efficiency show improvement in comparison with previous results [1,2]. Improvement of current upper limits on mixing elements between heavy and active neutrinos is expected due to increased statistics, inclusion of pion decays and additional heavy neutrino three-body decay channels. In this talk, systematic uncertainties, background estimations and expected sensitivity towards mixing elements will be presented.
The work is supported by Russian Science Foundation (RSF) grant №22-12-00358. The author is grateful for the assistance given by Y. Kudenko, A. Izmaylov and T2K collaboration members.
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Abe K., et al. "Search for heavy neutrinos with the T2K near detector ND280." Physical Review D 100.5 (2019): 052006
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Antel C., et. al. "Feebly Interacting Particles: FIPs 2022
workshop report". arXiv.2305.01715, pp. 278-281
