Vector Dark Matter Detection using the Quantum Jump of Atoms

TL;DR

This paper proposes a method to detect vector dark matter particles around 10^{-5} eV by tuning atomic energy levels with the Zeeman effect to induce observable photon emissions, linking dark matter detection to inflation scale insights.

Contribution

It introduces a novel atomic transition-based detection technique for vector dark matter, utilizing the Zeeman effect to match atomic energy gaps with dark matter mass.

Findings

Enhanced detection rate due to high spectral density of vector bosons.

Feasibility of using hydrogen atoms and ions for detection.

Potential to probe inflationary physics through dark matter detection.

Abstract

The hidden sector U(1) vector bosons created from inflationary fluctuations can be a substantial fraction of dark matter if their mass is around $10^{-5}$eV. The creation mechanism makes the vector bosons' energy spectral density $\rho_{cdm}/\Delta E$ very high. Therefore, the dark electric dipole transition rate in atoms is boosted if the energy gap between atomic states equals the mass of the vector bosons. By using the Zeeman effect, the energy gap between the 2S state and the 2P state in hydrogen atoms or hydrogen like ions can be tuned. The $2S$ state can be populated with electrons due to its relatively long life, which is about $1/7$s. When the energy gap between the semi-ground $2S$ state and the 2P state matches the mass of the cosmic vector bosons, induced transitions occur and the 2P state subsequently decays into the 1S state. The $2P\to1S$ decay emitted Lyman-$\alpha$ photons can then be registered. The choices of target atoms depend on the experimental facilities and the mass ranges of the vector bosons. Because the mass of the vector boson is connected to the inflation scale, the proposed experiment may provide a probe to inflation.