Search for New Physics via Low-Energy Electron Recoils with a 4.2 Tonne\times Year Exposure from the LZ Experiment

TL;DR

This paper presents the results of a search for new physics signals in electron recoils using 4.2 tonne-years of data from the LZ experiment, setting new constraints on several dark matter and solar particle models.

Contribution

The study provides the most stringent constraints to date on solar axion-like particles and mirror dark matter using low-energy electron recoil data from the LZ experiment.

Findings

No excess above background observed.

Stringent limits set on solar ALPs with keV masses.

Competitive constraints on mirror dark matter.

Abstract

We report results from searches for new physics models via electron recoils using data collected by the LUX-ZEPLIN (LZ) experiment during its first two science runs, with a total exposure of 4.2 tonne-years. The observed data are consistent with a background-only hypothesis. Constraints are derived for several new physics models that predict electronic recoil signals, including electromagnetic interactions of solar neutrinos, solar axion-like particles (ALPs), mirror dark matter, and the absorption of bosonic dark matter candidates. These results represent the most stringent constraints to date for solar ALPs with keV-scale masses and mirror dark matter, and they are competitive with existing limits for other investigated models.