# Flavour diagonal SUSY breaking

Because there is a single Yukawa matrix for the SM leptons, the lepton mass and flavour states can be aligned, by diagonalization, even if the Yukawa matrix had off-diagonal elements.

SUSY breaking, however, introduces soft-breaking masses for the sleptons, which could be off-diagonal and introduce flavour-changing currents, e.g. $e\to \mu \gamma$. What, in general, is the connection between the soft-breaking mass and the Yukawa coupling?

I know that in mSUGRA they can be connected by the Kahler potential, but is there any symmetry principle that can connect the two? I understand that the connection in mSUGRA arises only from minimality and nothing deeper? Surely this alignment cannot be an accident?

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