Non-minimal quartic inflation in classically conformal U(1)$_X$ extended Standard Model

TL;DR

This paper explores a classically conformal U(1)_X extended Standard Model where the U(1)_X gauge symmetry is radiatively broken, linking inflationary predictions with collider searches for Z' bosons and right-handed neutrinos.

Contribution

It introduces a novel inflationary scenario with non-minimal coupling in a conformal U(1)_X extension, connecting inflationary parameters to collider phenomenology.

Findings

Inflationary predictions are correlated with U(1)_X gauge coupling.

Current LHC constraints limit the model's parameter space.

Future colliders could detect Z' bosons and RHNs predicted by the model.

Abstract

We propose quartic inflation with non-minimal gravitational coupling in the context of the classically conformal U(1)_X extension of the SM. In this model, the U(1)_X gauge symmetry is radiatively broken through the Coleman-Weinberg (CW) mechanism, by which the U(1)_X gauge boson (Z' boson) and the right-handed neutrinos (RHNs) acquire their masses. We consider their masses in the range of O(10 GeV)-O(10 TeV), which are accessible to high energy collider experiments. The radiative U(1)_X gauge symmetry breaking also generates a negative mass squared for the SM Higgs doublet, and the electroweak symmetry breaking occurs subsequently. We identify the U(1)_X Higgs field with inflaton and calculate the inflationary predictions. Due to the CW mechanism, the inflaton quartic coupling during inflation, which determines the inflationary predictions, is correlated to the U(1)_X gauge coupling. With this correlation, we investigate complementarities between the inflationary predictions and the current constraint from the Z' boson resonance search at the LHC Run-2 as well as the prospect of the search for the Z' boson and the RHNs at the future collider experiments. The radiative U(1)_X gauge symmetry breaking also generates a negative mass squared for the SM Higgs doublet, and the electroweak symmetry breaking occurs subsequently. We identify the U(1)_X Higgs field with inflaton and calculate the inflationary predictions. Due to the Coleman-Weinberg mechanism, the inflaton quartic coupling during inflation, which determines the inflationary predictions, is correlated to the U(1)_X gauge coupling. With this correlation, we investigate complementarities between the inflationary predictions and the current constraint from the Z' boson resonance search at the LHC Run-2 as well as the prospect of the search for the Z' boson and the RHNs at the future collider experiments.