Electroweak breaking and Dark Matter from the common scale

TL;DR

This work proposes a classically scale-invariant extension of the Standard Model featuring a dark $U(1)_X$ sector with a doubly charged scalar $Φ$ and a Majorana fermion $N$. The Coleman–Weinberg mechanism induces a radiative breaking along a flat direction, linking the electroweak scale to the dark-sector scale via the Higgs portal, while a remnant $Z_2$ stabilizes $N$ as a dark matter candidate. DM annihilation proceeds mainly through $NN\to φφ$, fixing the relic abundance and driving the dark-sector couplings to values that yield a scalon mass $m_φ^2=8 B v_r^2$; the interplay yields a DM mass in the range $500$ GeV to a few TeV and typically order-one hidden-sector couplings. The scenario also imposes collider constraints on the Higgs–scalon mixing, with the overall result that a consistent, testable connection between electroweak breaking and dark matter mass can arise from a common scale in a scale-invariant framework.

Abstract

We propose a classically scale invariant extension of the Standard Model where the electroweak symmetry breaking and the mass of the Dark Matter particle come from the common scale. We introduce $U(1)_X$ gauge symmetry and $X$-charged scalar $Φ$ and Majorana fermion $N$. Scale invariance is broken via Coleman-Weinberg mechanism providing the vacuum expectation value of the scalar $Φ$. Stability of the dark matter candidate $N$ is guaranteed by a remnant $Z_2$ symmetry. The Higgs boson mass and the mass of the Dark Matter particle have a common origin, the vacuum expectation value of $Φ$. Dark matter relic abundance is determined by annihilation $NN \to ΦΦ$. We scan the parameter space of the model and find the mass of the dark matter particle in the range from 500 GeV to a few TeV.

Figures (2)

• Figure 1: Mass of the DM candidate $m_N$ (left) and dark sector gauge coupling $g_X$ (right) as a function of dark gauge boson mass $m_X$ and the scalon mass $m_\phi$. The lower region on the plot is excluded by the LHC bound on $\sin\theta$.
• Figure 2: Mixing angle $\sin\theta$ (left) and the vev of $\Phi$, $v_\Phi$ (right) as a function of dark gauge boson mass $m_X$ and the scalon mass $m_\phi$. The lower region on the plot is excluded by the LHC bound on $\sin\theta$.