Supported matter sector

One can define up to 99 matter fields in a single model in SARAH. Each one of them can come with an arbitrary number of generations and can transform as any irreducible representation with respect to the defined gauge groups.

Supersymmetric models

The matter interactions in SUSY models are usually fixed by the superpotential and the soft SUSY-breaking terms. SARAHtakes as input the renormalisable terms in the superpotential

W = c_LL_iϕ̂_i + c_MM^i**jϕ̂_iϕ̂_j + c_TY^ijkϕ̂_iϕ̂_jϕ̂_k

which the user has to write in the model file, and automatically generates the corresponding soft-breaking terms

L_S**B, W = c_Lt_iϕ_i + c_MB^i**jϕ_iϕ_j + c_TT^ijkϕ_iϕ_jϕ_k + h.c.

c_L, c_M, c_T are real coefficients, while the linear, bilinear, and trilinear parameters are treated by default in the most general way by taking them as complex tensors of appropriate order and dimension. If identical fields are involved in the same coupling, SARAHalso derives the symmetry properties for the parameter.

In recent years models with Dirac gauginos have been largely explored. They feature mass terms of the form m_D^ϕ̂_iAλ_Aψ_i < mat**h > ,where < mat**h > λ_A is a gaugino and ψ_i the fermionic component of a chiral superfield ϕ̂_i in the adjoint representation of the gauge group A. In addition, there are new D-term couplings . To generate Dirac mass terms for all the gauginos, these models always come with an extended matter sector, including at least one singlet, one triplet under S**U(2), and one octet under S**U(3). Furthermore, these models generate new structures in the RGEs . All these are fully supported in SARAH.

Non-Supersymmetric models

For non-supersymmetric models, SARAH supports all general, renormalisable Lagrangians of the form

L = m_{ij}^2 \phi_i \phi_j + \frac{1}{3} \kappa_{ijk} \phi_i \phi_j \phi_k + \frac{1}{4} \lambda \phi_i \phi_j \phi_k \phi_l + M^F_{ij} \psi_i \psi_j + Y_{ijk} \phi_i \psi_i \psi_j

for scalars ϕ_i, and Weyl fermions ψ_j. The Lagrangian needs to be defined by the user in the model file. Note, that we have omitted a tadpole term, t**ϕ, for a gauge singlet, as it can always be absorbed in a shift of ϕ.

See also