and can also be the origin of the axion decay constant, inflation, and right-handed neutrino masses. Within this framework, the scale of weak interactions and of the Grand Unified Theory (GUT) need some explanation.

In ISS the weak scale is highly fine-tuned, for example by twenty orders of magnitude for $\tilde{m} = 10^{12}~{\rm GeV}$, and can be understood in the multiverse, which provides a coherent framework for understanding both the fine-tuning of the weak scale and the cosmological constant [@Weinberg:1987dv; @Agrawal:1997gf]. In the $SU(5)$ unified model introduced in this paper, the fields responsible for weak breaking, $H, \bar{H}$, and $SU(5)$ breaking, $\Sigma$, do not have supersymmetric mass terms and are massless in the supersymmetric flat-space limit. Once supersymmetry is broken and the cosmological constant is fine-tuned, supergravity interactions induce an effective superpotential $$W_{\rm eff} \sim \tilde{m} \times 
    \left( \Sigma^2, \; H \bar{H}, \; \frac{1}{\Lambda} \Sigma^3, \; 
    \frac{1}{\Lambda} H \Sigma \bar{H}, \; ...  \right).
\label{eq:W_effintro}$$ This yields an $SU(5)$ breaking vacuum $\langle \Sigma \rangle \sim 
O(\Lambda)$, and we choose order unity coefficients so that this vacuum expectation value (VEV) is somewhat less than $\Lambda$. The heavy $XY$ gauge supermultiplet lies just below $\Lambda$, while all other states in $H, \bar{H}, \Sigma$ 