Dr Phillip Litchfield (Imperial College London)Dr Phillip Litchfield (Imperial College London)
The discovery of neutrino oscillations driven by the U[e3] element of the PMNS mixing matrix has prompted a step change in the way neutrino oscillation experiments are analysed, commonly described by the shorthand of "switching from a 2-neutrino to 3-neutrino picture". The difference is less clear cut than this. On the one hand, some older measurements used parametrisations that implicitly assumed at least three neutrino flavours (and less commonly required 2 independent mass splittings). The more interesting change relates to the way oscillations are parametrised for fitting and inference. "Two flavour" analyses used parameters that -- regardless of how they were named -- directly described the shape of the observed data (the location and depth of a 'dip'), whereas newer analyses are explicitly concerned with mixing angles that are not direct observables and only related to the data through mathematical transformations. This has non-trivial consequences for inferences from the data. This poster highlights some of these unintended consequences and considers whether alternative formulations for analysing and presenting data are possible.
Dr Phillip Litchfield (Imperial College London)