Sufficient and Necessary Conditions for CP Conservation in the Case of Degenerate Majorana Neutrino Masses

We carry out a systematic study of the sufficient and necessary conditions for CP conservation in the leptonic sector with massive Majorana neutrinos. In particular, the emphasis is placed on the number of CP-violating phases in the presence of a partial mass degeneracy (e.g., m1=m2≠m3) or a complete mass degeneracy m1=m2=m3, where mi (for i=1, 2, 3) stand for the masses of three ordinary neutrinos. In the canonical seesaw model with three right-handed neutrino singlets, CP-violating phases in the special case of a partial (e.g., M1=M2≠M3) or complete (i.e., M1=M2=M3) mass degeneracy of three heavy Majorana neutrinos are also examined. In addition, we derive the renormalization-group equations of the weak-basis invariants in the effective theory with a general mass spectrum of Majorana neutrinos, to which the solutions establish the direct connection between CP violation at low- and high-energy scales.

Note:

28 pages, 2 tables, more discussions and references added, accepted for publication in Phys. Rev. D

Beyond the standard model
conservation law: CP
CP: violation
phase: CP
asymmetry: CP
neutrino: Majorana
neutrino: mass
neutrino: Majorana: mass
neutrino: singlet
neutrino: right-handed

References(73)

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