Vector dark matter production from inflation with symmetry breaking

TL;DR

This paper proposes a model where vector dark matter is produced from symmetry breaking at the end of inflation, with quantum fluctuations of the dark photon accounting for current dark matter density, and predicts cosmic string formation.

Contribution

It introduces a novel mechanism linking inflation, symmetry breaking, and vector dark matter production, including cosmic string formation and specific parameter ranges.

Findings

Dark photon fluctuations can account for dark matter density

Model predicts cosmic strings consistent with CMB bounds

Reheat temperature around 10^{12} GeV supports the scenario

Abstract

We present a scenario of vector dark matter production from symmetry breaking at the end of inflation. In this model, the accumulated energy density associated with the quantum fluctuations of the dark photon accounts for the present energy density of dark matter. The inflaton is a real scalar field while a heavy complex scalar field, such as the waterfall of hybrid inflation, is charged under the dark gauge field. After the heavy field becomes tachyonic at the end of inflation, rolling rapidly towards its global minimum, the dark photon acquires mass via the Higgs mechanism. To prevent the decay of the vector field energy density during inflation, we introduce couplings between the inflaton and the gauge field such that the energy is pumped to the dark sector. The setup can generate the observed dark matter abundance for a wide range of the dark photon's mass and with the reheat temperature around $10^{12}$ GeV. The model predicts the formation of cosmic strings at the end of inflation with the tensions which are consistent with the CMB upper bounds.