We present, how a systematic study of B→ DℓN (D→ KℓN) decays with ℓ= μ, τ, at Belle II (BESIII) can provide unambiguous signature of a heavy neutrino N and/or constrain its mixing with active neutrinos νℓ, which is parameterized by | UℓN| 2. Our constraint on | UμN| 2 that can be achieved from the full Belle II data is comparable with what can be obtained from the much larger data set of the upgraded LHCb. Additionally, our method offers better constraint on | UμN| 2 for mass of sterile neutrino mN< 2 GeV. We can also probe the Dirac and Majorana nature of N by observing the sequential decay of N, including suppression from observation of a displaced vertex as well as helicity flip, for Majorana N.
Bibliographical noteFunding Information:
The work of C.S.K. was supported in part by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (NRF2018R1A4A1025334). This work of D.S. was supported (in part) by the Yonsei University Research Fund (Post Doc. Researcher Supporting Program) of 2018 (project no.: 2018-12-0145).
All Science Journal Classification (ASJC) codes
- Engineering (miscellaneous)
- Physics and Astronomy (miscellaneous)