Flow based Po218-BiPo214 parent-child tagging in LUX-ZEPLIN as validation of Pb214 tagging methods

LUX-ZEPLIN (LZ) has the furthest physics reach of any xenon time projection chamber (TPC) dark matter detector built to date, however Rn-222 chain Pb-214 decays still present the largest background contribution to any low energy search. While LZ provides excellent discrimination against electron recoil (ER) backgrounds, like those produced by Pb-214 decays, additional mitigation methods can further reduce Pb-214 backgrounds to help LZ achieve its ultimate WIMP sensitivity. One such mitigation could be exploitation of spatial correlations between a particular Po-218 decay and its child Pb-214, separated by O(10) minute xenon flows. Convective flow in previous TPC experiments have made this method untenable, but this talk will demonstrate successful parent-child tagging of Po-218 and Bi-Po-214 pairs separated by up to 80 minutes. The potential reduction in Pb-214 rate achieved when applying this technique to a non-signal region in LZ's SR1 dataset will also be presented.