Speaker
Description
LUX-ZEPLIN (LZ) is a dark matter (DM) detection experiment that has demonstrated world-leading sensitivity to GeV-mass DM and $^{8}\mathrm{B}$ solar neutrinos. An ionization-only (S2-only) analysis can enhance LZ’s sensitivity to lower-mass DM, provided that electrode-related backgrounds can be effectively mitigated. Long-lived $^{210}\mathrm{Pb}$ on the electrode wires from $^{222}\mathrm{Rn}$ daughter plate-out during construction and in-situ accumulation from TPC operation contributes a significant low-energy background in the S2-only analysis. In addition, the sporadic emission of electrons in high-field regions near the wires can mimic DM signals, thereby presenting further challenges. In this presentation, I will show measurements of $^{210}\mathrm{Po}$ evolution on the electrode wires using LZ data, assess the low-energy background contribution from $^{210}\mathrm{Pb}$ and its daughters over long-duration science operations, and discuss the characteristics and possible origins of grid electron emission.
| Main Contribution topic | Direct detection |
|---|---|
| Secondary contribution topic | Light Dark Matter |