Testing non-unitarity of neutrino mixing matrices at neutrino factories

Abstract

For models with heavy fermionic fields, the deviation of the leptonic mixing matrix from unitarity is a generic feature and provides a window to probe physics at high scale We consider non-unitary effect in the Pμτ channel and and detectors at a distance of 2 km, 130 km and 3000 km using a Neutrino Factory as the source for Vμ's. We discuss the constraints that can be obtained on the moduli and phases of the parameters characterizing the violation of unitarity. We point out how the new CP violation phases present in the case of non-unitary mixing give rise to spurious ‘degenerate’ solutions in the parameter space and discuss how the true solutions can be extracted by performing measurements at various baselines.