Unitarity and vacuum stability constraints on the couplings of color octet scalars

TL;DR

This paper investigates theoretical constraints on the parameters of a color octet scalar model by applying unitarity and vacuum stability conditions, aiding in understanding its viability in particle physics.

Contribution

It provides the first comprehensive analysis of unitarity and vacuum stability constraints on the couplings of color octet scalars in extended scalar sectors.

Findings

Derived bounds on scalar couplings ensuring perturbative unitarity.

Established conditions for vacuum stability of the scalar potential.

Identified parameter regions consistent with theoretical constraints.

Abstract

The recent discovery of a 126 GeV boson at the LHC will be followed by a detailed examination of its couplings in order to determine whether this particle is the Higgs boson of the standard model or one of many particles of an extended scalar sector. One such extension with a rich phenomenology consists of a color octet electroweak doublet scalar. The most general renormalizable scalar potential contains twelve new parameters and it is therefore desirable to constrain them. We present theoretical constraints on these parameters obtained by requiring perturbative unitarity for two-to-two scalar scattering amplitudes at high energy and vacuum stability.