Search for Solar Boosted Dark Matter Particles at the PandaX-4T Experiment

TL;DR

This paper reports the first search for solar-boosted light dark matter particles using the PandaX-4T detector, setting new constraints on their interaction cross-section and mass range, and significantly improving previous limits.

Contribution

It introduces a novel method to detect solar-boosted light dark matter with xenon detectors and provides the most stringent constraints to date in the 0.02 to 10 MeV/c^2 mass range.

Findings

Set a new upper limit on dark matter-electron cross-section at 3.51 x 10^-39 cm^2

Achieved a 23-fold improvement over previous experimental bounds

Detected recoil signals consistent with boosted dark matter interactions

Abstract

We present a novel constraint on light dark matter utilizing $1.54$ tonne$\cdot$year of data acquired from the PandaX-4T dual-phase xenon time projection chamber. This constraint is derived through detecting electronic recoil signals resulting from the interaction with solar-enhanced dark matter flux. Low-mass dark matter particles, lighter than a few MeV/$c^2$, can scatter with the thermal electrons in the Sun. Consequently, with higher kinetic energy, the boosted dark matter component becomes detectable via contact scattering with xenon electrons, resulting in a few keV energy deposition that exceeds the threshold of PandaX-4T. We calculate the expected recoil energy in PandaX-4T considering the Sun's acceleration and the detection capabilities of the xenon detector. The first experimental search results using the xenon detector yield the most stringent cross-section of $3.51 \times 10^{-39}~\mathrm{cm}^2$ at $0.08~\mathrm{MeV}$/$c^2$ for a solar boosted dark matter mass ranging from $0.02$ to $10~ \mathrm{MeV}$/$c^2$, achieving a 23 fold improvement compared with earlier experimental studies.