Unitarity constraints on general scalar couplings with SARAH

Area of Science:

• High Energy Physics
• Theoretical Physics
• Computational Physics

Background:

• Beyond the Standard Model (BSM) theories require precise calculations for experimental constraints.
• Unitarity constraints are crucial for validating new physics models.
• Previous methods often relied on simplifying assumptions at high energies.

Purpose of the Study:

• To present an updated Mathematica package, SARAH, for calculating unitarity constraints in BSM models.
• To enable analytical and numerical computation of two-particle scattering matrices for scalars.
• To investigate constraints on scalar couplings at energies relevant to the weak scale.

Main Methods:

• Utilizing the SARAH package for Mathematica.
• Performing analytical and numerical calculations of the two-particle scattering matrix for uncoloured scalars.
• Including all relevant contributions at energies above the weak scale, avoiding high-energy approximations.

Main Results:

• The updated SARAH package can now calculate unitarity constraints without high-energy approximations.
• New functions allow for precise analysis of trilinear scalar couplings.
• Constraints on quartic couplings can be modified, as demonstrated with a singlet extended Standard Model example.

Conclusions:

• The enhanced SARAH package provides a more accurate tool for BSM physics research.
• This enables tighter constraints on scalar couplings in various BSM scenarios.
• The methodology is applicable to a wide range of BSM models beyond the Standard Model.