when you have a chiral superfield in the adjoint representation in your theory (i.e the Higgs $\Sigma_{24}$ in $SU(5)$), you can write it as a $5\times5$ Matrix: $(\Sigma_{24})_i^j=\Sigma^a (t^a)_i^j$ (sum over a), where the $t^a$ are the generatorns of the $SU(5)$.
My question is: is it possible that the $\Sigma_a$ are real, or do they have to be complex for $SU(5)$ SUSY GUT?
I'm asking because some steps in the calculation of the minimum (vev) seem to need real $\Sigma_a$'s, since that would make $\Sigma_{24}$ Hermitian. But on the other side I'm not sure if real scalars would make problems with supersymmetry (degrees of freedom).
thanks
Update:
The problem with real $\Sigma_a$ is the following:
Suppose you want to write down the superfield $S$ in components. For one complex scalar $\Phi$ it would look as follows: $S=\Phi+\sqrt{2} \theta \Psi+\theta\theta F$. Looking at the degrees of freedome on-shell $\rightarrow dof(\Phi)=2, dof(\Psi)=2,dof(F)=0$
Now looking at the adjoint representation of $\Sigma$, wich is a 24-dimesional multiplett ($\Sigma_1,...,\Sigma_{24}$)(this are the $\Sigma_a$ from above, (btw. $\Sigma_a=\Sigma^a$, sorry for mixing notation)). Now each field in this supermultiplett has to be a superfield, like above $\Sigma_a=\Phi_a+\sqrt{2} \theta \Psi_a+\theta\theta F_a$. Counting now the degress of freedome reveals the problem: $\rightarrow dof(\Phi_a)=1, dof(\Psi_a)=2,dof(F_a)=0$. That shows that the fermionic dof. are not equal to the bosonic dof. wich contradicts SUSY.
Edit:
$i,j$ in $\Sigma_i^j$ are matrix indices and run from 1 to 5.
$a$ in $t^a$ and $\Sigma^a$ runs from 1 to 24 (24 = dimension of adjoint representation of $SU(5)$)