Type: Article
Publication Date: 2004-07-16
Citations: 28
DOI: https://doi.org/10.1088/1367-2630/6/1/083
It is shown that eightfold degeneracy in neutrino oscillations is easily seen by plotting constant probabilities in the (sin2 2θ13, 1/s232) plane. Using this plot, we discuss how an additional long baseline measurement resolves degeneracies after the JPARC experiment measures the oscillation probabilities P(νμ→νe) and at |Δm312|L/4E = π/2. By measuring P(νμ→νe) or , the sgn(Δm312) ambiguity is resolved better at longer baselines and the δ↔π−δ ambiguity is resolved better when ||Δm312|L/4E − π/2| is larger. The θ23 ambiguity may be resolved as a by-product if ||Δm312|L/4E − π| is small and the CP phase δ turns out to satisfy |cos(δ+|Δm312|L/4E)| ∼ 1. It is pointed out that the low-energy option (E∼1 GeV) at the off-axis NuMI experiment may be useful in resolving these ambiguities. The νe→ντ channel offers a promising possibility that it would potentially resolve all the ambiguities.