SU(5)$\times$U(1)$_X$ grand unification with minimal seesaw and $Z^\prime$-portal dark matter

TL;DR

This paper introduces a grand unified SU(5)$\times$U(1)$_X$ model with minimal seesaw and right-handed neutrino dark matter, exploring its implications for collider searches, cosmology, and neutrino physics.

Contribution

It presents a novel SU(5)$\times$U(1)$_X$ GUT model incorporating minimal seesaw and stable right-handed neutrino dark matter, with detailed phenomenological analysis.

Findings

The $Z'$-portal RHN dark matter scenario is consistent with relic abundance constraints.

Future LHC experiments can fully probe the $Z'$ boson mass below 5 TeV.

The model can successfully incorporate baryogenesis and inflation mechanisms.

Abstract

We propose a grand unified SU(5)$\times$U(1)$_X$ model, where the standard SU(5) grand unified theory is supplemented by minimal seesaw and a right-handed neutrino dark matter with an introduction of a global $Z_2$-parity. In the presence of three right-handed neutrinos (RHNs), the model is free from all gauge and mixed-gravitational anomalies. The SU(5) symmetry is broken into the Standard Model (SM) gauge group at $M_{\rm GUT} \simeq 4 \times 10^{16}$ GeV in the standard manner, while the U(1)$_X$ symmetry breaking occurs at the TeV scale, which generates the TeV-scale mass of the U(1)$_X$ gauge boson ($Z^\prime$ boson) and the three Majorana RHNs. A unique $Z_2$-odd RHN is stable and serves as the dark matter (DM) in the present Universe, while the remaining two RHNs work to generate the SM neutrino masses through the minimal seesaw. We investigate the $Z^\prime$-portal RHN DM scenario in this model context, and find that the constraints from the DM relic abundance and the search results for a $Z^\prime$ boson resonance at the Large Hadron Collider (LHC) are complementary to narrow down the allowed parameter region, which will be fully covered by the future LHC experiments (for the $Z^\prime$ boson mass $<$ 5 TeV). We also briefly discuss the successful implementation of Baryogenesis and cosmological inflation scenarios in the present model.