Direct Detection Constraints on Dark Photons with CDEX-10 Experiment at the China Jinping Underground Laboratory

TL;DR

This paper reports new constraints on dark photon parameters using the CDEX-10 germanium detector data, exploring masses from 10 eV to 4 keV and setting upper limits on kinetic mixing.

Contribution

First direct detection constraints on dark photons in the 10 eV to 4 keV mass range using germanium detectors at the China Jinping Underground Laboratory.

Findings

Set 90% CL upper limits on kinetic mixing parameter for solar dark photons from 10 to 300 eV.

Established limits on dark matter dark photons with masses from 0.1 to 4.0 keV.

Achieved a minimum kinetic mixing limit of 1.3 x 10^{-15} at 200 eV mass.

Abstract

We report constraints on the dark photon effective kinetic mixing parameter (${\kappa}$) with data taken from two ${p}$-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90\% confidence level upper limits on ${\kappa}$ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (${m_V}$) from 10 to 300 eV/${c^2}$ in direct detection experiments. Considering dark photon as the cosmological dark matter, limits at 90\% confidence level with ${m_V}$ from 0.1 to 4.0 keV/${c^2}$ are set from 449.6 kg-day data, with a minimum of ${\rm{\kappa=1.3 \times 10^{-15}}}$ at ${\rm{m_V=200\ eV/c^2}}$.