Decoherence, matter effect, neutrino hierarchy signature in long baseline experiments

Environmental decoherence of oscillating neutrinos of strength $Gamma = (2.3 pm 1.1) times 10^{-23}$ GeV can explain how maximal $theta_{23}$ mixing observed at 295 km by T2K appears to be non-maximal at longer baselines. As shown recently by R. Oliveira, the MSW matter effect for neutrinos is altered by decoherence: In normal (inverted) mass hierarchy, a resonant enhancement of $ u_{mu} (bar{ u}_{mu}) rightarrow u_{e} (bar{ u}_{e})$ occurs for $6 < E_{ u} < 20$ GeV. Thus decoherence at the rated strength may be detectable as an excess of charged-current $ u_{e}$ events in the full $ u_{mu}$ exposures of MINOS+ and OPERA.