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Description
Current work aims at the study of heavy neutral leptons, or heavy neutrinos (N), in the mass range $<493 \, \text{MeV}/c^2$ [1]. These particles can be produced in charged pion and kaon decays in the T2K standard neutrino beam: $M^\pm \rightarrow l^\pm_\alpha N$, where ($M=\pi,K; \, \alpha=e,\mu$). Then, heavy neutrinos can decay in ND280 via the following two- and three-body decay modes: $N \rightarrow l^\pm_\alpha \pi^\mp, \, N \rightarrow l^+_\alpha l^-_\beta \nu(\bar{\nu}$), where ($\alpha,\beta = e,\mu$). In order to reduce background from neutrino interactions, we search for heavy neutrino decays in the volume of the Time Projection Chambers (TPCs). The heavy neutrino mass range considered in the current work is wider compared to the previous T2K analysis [2, 3] due to the inclusion of pion decays. Moreover, additional statistics, new Monte Carlo model and updated TPC reconstruction algorithm are used in current analysis. Preliminary constraints on mixing elements between heavy and active neutrinos will be presented.
The work is supported by Russian Science Foundation (RSF) grant № 26-12-00495. Authors are grateful for the assistance given by Y. Kudenko, P. Litchfield and T2K collaboration members.
- Asaka T. and Shaposhnikov M. "The MSM, dark matter and baryon asymmetry of the Universe". Physics Letters B, 620, 17-26 (2005).
- Abe K., et al. "Search for heavy neutrinos with the T2K near detector ND280". Physical Review D 100.5 (2019): 052006
- Antel C., et. al. "Feebly Interacting Particles: FIPs 2022 workshop report". arXiv.2305.01715, pp. 278-281
