Searching for non-unitary neutrino oscillations in the present T2K and NO nu A data

Author(s)

Miranda, Luis Salvador ^{[1, 2]} ; Pasquini, Pedro ^{[3, 4, 5]} ; Rahaman, Ushak ^{[1, 2]} ; Razzaque, Soebur ^{[1, 2]}

Affiliation

^[1] Univ Johannesburg, Dept Phys, POB 524, ZA-2006 Auckland Pk - South Africa

^[2] Univ Johannesburg, Ctr Astroparticle Phys CAPP, POB 524, ZA-2006 Auckland Pk - South Africa

^[3] Shanghai Jiao Tong Univ, Sch Phys & Astron, Shanghai 200240 - Peoples R China

^[4] Univ Estadual Paulista UNESP, Inst Fis Teor, R Dr Bento Teobaldo Ferraz 271, BR-01140070 Sao Paulo, SP - Brazil

^[5] Shanghai Jiao Tong Univ, Tsung Dao Lee Inst, Shanghai 200240 - Peoples R China

• Document type: Journal article
• Source: EUROPEAN PHYSICAL JOURNAL C; v. 81, n. 5 MAY 2021.
• Web of Science Citations: 0

Abstract

The mixing of three active neutrino flavors is parameterized by the unitary PMNS matrix. If there are more than three neutrino flavors and if the extra generations are heavy iso-singlets, the effective 3 x 3 mixing matrix for the three active neutrinos will be non-unitary. We have analyzed the latest T2K and NO nu A data with the hypothesis of non-unitary mixing of the active neutrinos. We found that the 2019 NO nu A data slightly (at similar to 1 sigma CL) prefer the non-unitary mixing over unitary mixing. In fact, allowing the non-unitary mixing brings the NO nu A best-fit point in the sin(2) theta(23) - delta(CP) plane closer to the T2K best-fit point. The 2019 T2K data, on the other hand, cannot rule out any of the two mixing schemes. A combined analysis of the NO nu A and T2K 2019 data prefers the non-unitary mixing at 1 s CL. We derive constraints on the non-unitary mixing parameters using the best-fit to the combined NO nu A and T2K data. These constraints are weaker than previously found. The latest 2020 data from both the experiments prefer non-unitarity over unitary mixing at 1 sigma CL. The combined analysis prefers non-unitarity at 2 sigma CL. The stronger tension, which exists between the latest 2020 data of the two experiments, also gets reduced with non-unitary analysis. (AU)

• FAPESP's process: 14/19164-6 - Challenges in the 21st century in neutrino physics and astrophysics
• Grantee: Orlando Luis Goulart Peres
• Support Opportunities: Special Projects