Abstract
We present an update of the Mathematica package SARAH to calculate unitarity constraints in BSM models. The new functions can perform an analytical and numerical calculation of the two-particle scattering matrix of (uncoloured) scalars. We do not make use of the simplifying assumption of a very large scattering energy, but include all contributions which could become important at small energies above the weak scale. This allows us to constrain trilinear scalar couplings. However, it can also modify (weakening or strengthening) the constraints on quartic couplings, which we show via the example of a singlet extended Standard Model.
Highlights
In a classic paper, Lee, Quigg and Thacker showed that the Higgs mass in the Standard Model (SM) must be below 1 TeV in order to maintain perturbative unitarity [1]
We present an update of the Mathematica package SARAH to calculate unitarity constraints in BSM models
For this purpose we have extended the Mathematica package SARAH [20,21,22,23,24] by routines for the analytical and numerical study of the full tree-level unitarity constraints
Summary
Lee, Quigg and Thacker showed that the Higgs mass in the Standard Model (SM) must be below 1 TeV in order to maintain perturbative unitarity [1]. 4. Even for theories with a high cutoff, the infinite energy approximation is rarely justified since the couplings must run: if we take the energy sufficiently high to be able to neglect particle masses, the resummed couplings will typically have completely different values. Even for theories with a high cutoff, the infinite energy approximation is rarely justified since the couplings must run: if we take the energy sufficiently high to be able to neglect particle masses, the resummed couplings will typically have completely different values For this purpose we have extended the Mathematica package SARAH [20,21,22,23,24] by routines for the analytical and numerical study of the full tree-level unitarity constraints.
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