Probing non-unitary neutrino mixing using atmospheric neutrinos at INO-ICAL
Published in Springer Proc. Phys., 2024
Recommended citation: Sadashiv Sahoo, Sudipta Das, Anil Kumar, Sanjib Kumar Agarwalla, "Probing non-unitary neutrino mixing using atmospheric neutrinos at INO-ICAL", Proceedings of the XXV DAE-BRNS High Energy Physics (HEP) Symposium 2022, IISER, Mohali, India, 12-16 Dec, 2022. Springer Proc. Phys. 304 (2024) 290-293. https://doi.org/10.1007/978-981-97-0289-3_63
Conference: The XXV DAE-BRNS High Energy Physics (HEP) Symposium 2022, IISER, Mohali, India, 12-16 Dec, 2022.
Abstract: The mixing among three light active neutrinos is parametrized using the unitary PMNS matrix. If there are additional neutrinos present in Nature which are heavy iso-singlets, then the effective mixing matrix for the light three active neutrinos would be non-unitary. Because of this non-unitary neutrino mixing (NUNM), the oscillation probabilities between the three active neutrinos would be altered as compared to the probabilities obtained under the assumption of a unitary PMNS matrix. Atmospheric neutrinos have access to a wide range of energies and baselines, which can feel the presence of such NUNM in Earth’s matter effect. In this talk, I will discuss the possible constraints that can be placed on the NUNM parameter ($\alpha_{32}$) in a model-independent fashion using the proposed 50 kt magnetized Iron Calorimeter (ICAL) detector under the India-based Neutrino Observatory (INO) project, which can efficiently detect the atmospheric $\nu_\mu$ and $\bar{\nu}_\mu$ and separately in the multi-GeV energy range passing through deep inside the Earth.