Seesaw light-mass estimate needs a Dirac scale
= Seesaw light-mass estimate needs a Dirac scale
{title2=$m_\nu\simeq m_D^2/M_R$}
In the type-I regime $M_L\simeq0$, $M_R\gg m_D$, the light <mass> is $m_D^2/M_R$. Specifying only the right-handed scale does not fix a numerical light <mass>. A choice of Dirac <mass> is an extra assumption, not a result of <matrix> diagonalization.