Conformal Complex Scalar Singlet Extensions of the Standard Model: Symmetry Breaking Patterns and Phenomenology

TL;DR

This paper explores a conformal complex singlet extension of the Standard Model, analyzing symmetry breaking, dark matter candidates, and potential collider signatures, with implications for asymptotic safety and LHC phenomenology.

Contribution

It introduces a novel conformal complex singlet model with distinct symmetry breaking scenarios and connects UV boundary conditions to TeV-scale physics and collider phenomenology.

Findings

Unbroken phase provides a stable dark matter candidate.

Broken phase predicts a second Higgs at 554 GeV.

Model suggests testable LHC signatures like diboson excesses.

Abstract

We consider a conformal complex singlet extension of the Standard Model with a Higgs portal interaction. Two different scenarios depending on whether the global U(1) symmetry is broken or not have been studied. In the unbroken phase, the decay of the complex singlet is protected by the global U(1) symmetry which leads to an ideal cold dark matter candidate. In the broken phase, we are able to provide a second Higgs at $554\,\rm{GeV}$. In addition, gauging the global U(1) symmetry, we can construct an asymptotically safe U(1)' leptophobic model. We combine the notion of asymptotic safety with conformal symmetry and use the renormalization group equations as a bridge to connect UV boundary conditions and Electroweak/ TeV scale physics. We also provide a detailed example to show that these boundary conditions will lead to phenomenological signatures such as diboson excesses which could be tested at the LHC.