Anomalies in several short-baseline neutrino oscillation experiments suggest the possible existence of sterile neutrinos at about the eV scale that have appreciable mixing with the three known neutrinos. We find that if such a light sterile neutrino exists, through a combined study of the leptonic decays of μ-, τ-, π-, and K-, some semileptonic decays of τ- and the invisible decay width of the Z boson, it is possible to constrain the relevant mixing matrix elements. Furthermore, we compare the constraints, derived by using the method presented here, with the experimental results obtained from short-baseline neutrino oscillation experiments. We find that a single light sterile neutrino cannot satisfy the existing short-baseline neutrino oscillation constraints and explain the anomalies mentioned above. Along the way we provide a number of experimentally clean observables which can be used to directly study the light sterile neutrino independently of the neutrino oscillation experiments.
Bibliographical noteFunding Information:
This work of C. S. K. and D. S. was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) No. 2018R1A4A1025334. G. L. C. is grateful to Conacyt for financial support under Project No. 236394. This work of D. S. was also supported (in part) by the Yonsei University Research Fund (Post Doc. Researcher Supporting Program) of 2018 (Project No. 2018-12-0145). We would also to thank the anonymous referee whose suggestions have improved our discussion of the results and the overall presentation.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)