Non-standard neutrino oscillations: perspective from unitarity triangles

A bstract We formulate an alternative approach based on unitarity triangles to describe neutrino oscillations in presence of non-standard interactions (NSI). Using perturbation theory, we derive the expression for oscillation probability case NSI and cast it terms three independent parameters leptonic triangle (LUT). The form invariance (even new physics scenario as long mixing matrix is unitary) facilitates a neat geometric view LUT. examine regime validity perturbative expansions make comparisons with approximate expressions existing literature. uncover some interesting dependencies while studying evolution LUT Jarlskog invariant. Interestingly, allows us express probabilities given pair flavours only (and not four) degrees freedom which are related properties (sides angles) triangle. Moreover, invariant under rephasing transformations parameterization adopted.