Supported global symmetries
SARAH can handle an arbitrary number of global symmetries which are either ZN or U(1) symmetries. Also a continuous R-symmetry U(1)R is possible. Global symmetries are used in SARAH mainly for three different purposes: first, they help to constrain the allowed couplings in the superpotential. However, SARAH doesn’t strictly forbid terms in the superpotential which violate a global symmetry. SARAH only prints a warning to point out the potential contradiction. The reason is that such a term might be included on purpose to explain its tininess. Global symmetries can also affect the soft-breaking terms written down by SARAH. SARAH always tries to generate the most general Lagrangian and includes also soft-masses of the form m2ϕiϕj</sup> for two scalars ϕi,ϕj with identical charges. However, these terms are dropped if they are forbidden by a global symmetry. By the same consideration, Dirac gaugino mass terms are written down or not. Finally, global symmetries are crucial for the output of model files for MicrOmegas to calculate the relic density. For this output at least one unbroken discrete global symmetry must be present. By modifying the global symmetries one can already go beyond the MSSM without changing the particle content: choosing a Z3 (Baryon triality) instead of R-Parity , lepton number violating terms would be allowed while the proton is still stable. SARAH comes not only with R-parity violating models based on Baryon triality, but also a variant for Baryon number violation but conserved Lepton number is included.