Observing dark photon with dark matter detectors

TL;DR

This paper investigates the detection of light dark photons produced in the Sun using dark matter detectors, setting new experimental limits on their properties and comparing sensitivities with astrophysical constraints.

Contribution

It provides the most stringent laboratory limits on dark photon parameters for masses below 1 keV using XENON10 data, and analyzes the impact of a potential light Higgs boson.

Findings

XENON10 sets limits of κ m_V < 3×10^{-12} eV for m_V < 10^3 eV.

Sensitivity to light Higgs bosons with κ e' < 10^{-13} is established.

Astrophysical constraints from horizontal branch stars are more restrictive than current laboratory bounds.

Abstract

Motivated by various kinds of new physics models, a new light neutral vector boson (the dark photon) connected to the Standard Model of particle physics only through the kinetic mixing with the U(1)_Y factor has been studied extensively. Various kinds of experiments are proposed to detect it. For the dark photon with a mass smaller than 10 keV, it can be copiously produced inside the Sun, and then be detected by the detectors on the earth. We show that with the S2 only analysis, the result from XENON10 experiment provides the up-to-date most stringent limit on the region 10^{-5} eV < m_V < 10^3 eV: kappa m_V < 3 times 10^{-12} eV for the Stueckelberg dark photon model, where kappa is the kinetic mixing and m_V is the mass of the dark photon. If there is a light Higgs boson accompanied with the dark photon, the sensitivity of XENON10 experiment is kappa times e' < 10^{-13}, which is still second to the constraints from the lifetime of horizontal branch starts which dictates kappa times e' < 3 times10^{-14}.