Some New Symmetric Relations and the Prediction of Left and Right Handed   Neutrino Masses using Koide's Relation
  Masses of the three generations of charged leptons are known to completely satisfy the Koide's mass relation. But the question remains if such a relation exists for neutrinos? In this paper, by considering SeeSaw mechanism as the mechanism generating tiny neutrino masses, we show how neutrinos satisfy the Koide's mass relation, on the basis of which we systematically give exact values of not only left but also right handed neutrino masses. 
Yong-Chang Huang, Syeda Tehreem Iqbal, Zhen Lei and Wen-Yu Wang
hep-ph