Detection Prospects of Millicharged Dark Matter in Unconventional Interferometer

TL;DR

This paper proposes using an unconventional laser interferometer to detect earth-captured millicharged particles by observing photon phase shifts, potentially revealing particles with extremely small fractional charges in a broad mass range.

Contribution

It introduces a novel detection method for earth-bound millicharged particles using laser interferometry, enhancing sensitivity to fractional charges over a wide mass spectrum.

Findings

Sensitivity to fractional charge $ imes 10^{-12}$ to $10^{-6}$

Detectable number density greater than 1 cm$^{-3}$

Mass range between 1 GeV and 10$^{12}$ GeV

Abstract

We propose a novel idea to discover millicharged particles (mCPs) captured by the earth during its existence. It has been demonstrated that the mCPs accumulation inside the earth leads to the enhancement of its number density much larger than the corresponding virial density. We propose to utilize an unconventional laser interferometer to probe these earth-bound mCPs through the detection of the photons's phase shift. We demonstrate that, for mCPs mass in the range between $1$ GeV to $10^{12}$ GeV, the sensitivity of probing their fractional electric charge $\epsilon$ could reach as low as $10^{-12}$ to $10^{-6}$ provided that mCPs number density is greater than $1~\text{cm}^{-3}$.