Exploring neutrino mixing with low energy superbeams
Abstract
We explore the features of neutrino oscillation which are relevant for measurements of the leptonic CP violating phase δ and the sign of Δm213 in experiments with low-energy conventional superbeams. Toward the goal, we introduce a new powerful tool called the ``CP trajectory diagram in bi-probability space'' which allows us to represent pictorially the three effects, the effects of (a) genuine CP violation due to the sin δ term, (b) CP conserving cos δ term, and (c) fake CP violation due to earth matter, separately in a single diagram. By using the diagram, we observe that there is a two-fold ambiguity in the determination of δ which is related with the sign of Δm213. Possible ways of resolving the ambiguity are discussed. In particular, we point out that an in situ simultaneous measurement of δ and the sign of Δm213 can be carried out at distances of about 700 km, or at the Phase II of the JHF experiment provided that sin δ · Δm213 < 0, both with a megaton class water Cherenkov detector.
- Publication:
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Journal of High Energy Physics
- Pub Date:
- October 2001
- DOI:
- 10.1088/1126-6708/2001/10/001
- arXiv:
- arXiv:hep-ph/0108085
- Bibcode:
- 2001JHEP...10..001M
- Keywords:
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- High Energy Physics - Phenomenology
- E-Print:
- 31 pages, 8 figures, in JHEP style