Superpotential
A generic invariant renormalizable superpotential is a (complex) invariant cubic polynomial in the superfields which has an R-charge of 2. It is a linear combination of the following terms:
The second column expands each term in index notation (neglecting the proper normalization coefficient). i and j are the generation indices. The coupling Hd 10i 10j has coefficients which are symmetric in i and j.
In those models without the optional φ sterile neutrinos, we add the nonrenormalizable couplings instead.
These couplings do break the R-symmetry.
Read more about this topic: Flipped SU(5)