Martin GabelmannPresence of super-heavy particles
Extensions of the SM can not only be present at the SUSY scale but also appear at much higher scales. These superheavy states have then only indirect effects on the SUSY phenomenology compared to the MSSM: they alter the RGE evolution and give a different prediction for the SUSY parameters. In addition, they can also induce higher dimensional operators which are important. SARAH provides features to explore models with superheavy states: it is possible to change stepwise the set of RGEs which is used to run the parameters numerically with SPheno. In addition, the most important thresholds are included at the scale MT at which the fields of mass M are integrated out. These are the corrections to the gauge couplings and gaugino masses
g_A \rightarrow g_A \left( 1\pm \frac{1}{16 \pi^2} g_A^2 S^A(r) \ln\left(\frac{M^2}{M_T^2}\right)\right),\\ M_A \rightarrow M_A \left( 1\pm \frac{1}{16 \pi^2} g_A^2 S^A(r) \ln\left(\frac{M^2}{M_T^2}\right)\right).
SA(r) is the Dynkin index of a superfield transforming as representation r with respect to the gauge group A. When evaluating the RGEs from the low to the high scale the contribution is positive, when running down, it is negative. Eqs. ([eq:shift1])–([eq:shift2]) assume that the mass splitting between the components of the chiral superfield integrated out is negligible. That’s often a good approximation for very heavy states. Nevertheless, SARAH can also take into account the mass splitting among the components if necessary. Also higher dimensional operators can be initialized which give rise to terms like eq. ([eq:WW]). However, those are only partially supported in SARAH. That means that only the RGEs are calculated for these terms and the resulting interactions between two fermions and two scalars are included in the Lagrangian. The six scalar interactions are not taken into account. This approach is for instance sufficient to work with the Weinberg operator necessary for neutrino masses .