Calculating the renormalisation group equations of a SUSY model with Susyno

Susyno is a Mathematica package dedicated to the computation of the 2-loop renormalisation group equations of a supersymmetric model based on any gauge group (the only exception being multiple U(1) groups) and for any field content. Supersymmetry (SUSY) is an elegant and well known extension of the Standard Model (SM) which aims at solving or softening some of the SM theoretical and experimental shortcomings. Supersymmetric models based on Grand Unified Theories (GUTs) offer the appealing feature of being described by a unique gauge group and coupling constant; furthermore, the potential new superfields, as well as their dynamics, can provide answers to fundamental problems. For example SO(10) based models offer a natural explanation for neutrino masses and mixings via a type-I seesaw. This occurs since the spinor representation of the group contains a SM singlet superfield (with the appropriate quantum numbers). Even larger and/or more complex groups are often considered, for example E6 in string inspired models. The analysis of the theoretical and phenomenological implications of SUSY GUT models requires a careful study of the evolution of the fundamental parameters from the high-energy scale down to the electroweak scale, at which observables are computed and constraints applied. As such, knowledge of the renormalisation group equations (RGEs) is necessary. Although the RGEs of several models (e.g., MSSM, NMSSM) are already known [1, 3], for other SUSY extensions of the SM complicated general equations must be used [1, 2]. Here we describe Susyno, a Mathematica-based package that addresses this issue. The program takes as input the gauge group, the representations (i.e., the chiral superfield content), the number of flavours/copies 1 of each representation, and any abelian discrete symmetries (e.g., R-parity). Susyno then constructs the most general superpotential and soft SUSY breaking Lagrangian consistent with the field content and symmetries imposed. Once these elements have been derived, Susyno then computes the 2-loop �-functions of all the parameters of the model, which is its main output.