Parameter Degeneracies in Neutrino Oscillation Measurement of Leptonic CP and T Violation

Aug, 2002
34 pages
Published in:
  • Phys.Rev.D 66 (2002) 093012
e-Print:
Report number:
  • FERMILAB-PUB-02-184-T,
  • IFT-P-052-2002

Citations per year

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Abstract:
The measurement of the mixing angle \theta_{13}, sign of \Delta m^2_{13} and the CP or T violating phase \delta is fraught with ambiguities in neutrino oscillation. In this paper we give an analytic treatment of the paramater degeneracies associated with measuring the \nu_\mu -> \nu_e probability and its CP and/or T conjugates. For CP violation, we give explicit solutions to allow us to obtain the regions where there exist two-fold and four-fold degeneracies. We calculate the fractional differences, \Delta \theta / \bar{\theta}, between the allowed solutions which may be used to compare with the expected sensitivities of the experiments. For T violation we show that there is always a complete degeneracy between solutions with positive and negative \Delta m^2_{13} which arises due to a symmetry and cannot be removed by observing one neutrino oscillation probability and its T conjugate. Thus, there is always a four fold parameter degeneracy apart from exceptional points. Explicit solutions are also given and the fractional differences are computed. The bi-probability CP/T trajectory diagrams are extensively used to illuminate the nature of the degeneracies.
Note:
  • 35 pages, Latex, 11 postscript figures, minor corrections Report-no: Fermilab-Pub-02/0184-T and IFT-P.052/2002
  • neutrino: oscillation
  • neutrino/e
  • neutrino/mu
  • neutrino: mixing angle
  • neutrino: mass difference
  • CP: violation
  • time reversal: violation
  • numerical calculations
  • bibliography
  • 14.60.Pq