Higher dimensionsal terms in superpotential
SARAH is mainly restricted to renormalisable operators. The only exception are the possibility to include interactions of four superfields in the Superpotential:
SuperPotential = ... + [Coefficient] EffOp [Contraction] SuperField1.SuperField2.SuperField3.SuperField4
SARAH can't so far not include the entire impact of this operator but the following aspects are covered:
- A soft-term involving four scalars is added (
- The RGEs for the superpotential term and the soft-term are calculated
- The four scalar and two scalar-two fermion interactions are added to the Lagrangian. However, for the FFSS interactions only those terms are included in the calculation where at least one scalar is replaced by a VEV, i.e. effective FFS and FF terms are generated.
Despite the many limitations in the support of such terms, the given functionality is sufficient to include all important effects from the Weinberg operator. Adding the term
SuperPotential = WOp/2 Hu.l.Hu.l
to the superpotential, SARAH calculates the RGEs for
WOp and uses it to obtain neutrino masses.