Testing T2K's Bayesian constraints with priors in alternate parameterisations

TL;DR

This paper investigates how different prior choices in Bayesian analysis affect the interpretation of T2K neutrino oscillation data, finding that some parameters are robust while others depend on prior assumptions.

Contribution

It explores the impact of alternative parameterisations on Bayesian constraints in neutrino physics, highlighting the robustness and sensitivity of different parameters.

Findings

CP violation constraints are robust across priors

Octant preference depends on the chosen symmetry

Prior choice influences some parameter inferences

Abstract

Bayesian analysis results require a choice of prior distribution. In long-baseline neutrino oscillation physics, the usual parameterisation of the mixing matrix induces a prior that privileges certain neutrino mass and flavour state symmetries. Here we study the effect of privileging alternate symmetries on the results of the T2K experiment. We find that constraints on the level of CP violation (as given by the Jarlskog invariant) are robust under the choices of prior considered in the analysis. On the other hand, the degree of octant preference for the atmospheric angle depends on which symmetry has been privileged.