Biswajit Karmakar, Seminar #6: "Life on the far side of U_PMNS"

by Dr Biswajit Karmakar

Wednesday 3 Sept 2025, 10:15 → 11:15 Europe/Zurich

Lecture Hall (1st Wing)

Abstract: The pattern of neutrino mixing, usually parameterized by the Pontecorvo–Maki–Nakagawa–Sakata matrix (U_PMNS), still remains a striking puzzle in particle physics. U_PMNS is one of six possible products of multiplying three Euler matrices. Here we propose the neutrino mixing matrix parameterization for three known flavours of neutrinos based on SO(3) group, represented by one three-dimensional rotation matrix U_SO3. This mixing matrix with cyclic order of the group's Lie generators implies delta_CP=180 for clockwise rotation in three dimensions, a viable scenario for normal neutrino mass ordering. We determine the range of rotation angles for U_SO3 parameterization, which deviates substantially from the almost maximal mixings in the standard U_PMNS scenario. With the fixed delta_CP value, the U_SO3 parameterization can be validated or falsified by the next generation of neutrinoless double beta decay experiments and puts a stringent constraint on the absolute neutrino mass. The proposed  U_SO3  neutrino mixing parameterization is suited for independent  CP-conserving neutrino oscillation experimental analysis.  

bk_SO3_zg.pdf