An Effective Field Theory Dark Matter Search Using High Energy Nuclear Recoil in the LZ Experiment.

The existence of Dark Matter is well motivated from astrophysical and cosmological observations but, as yet, has not been observed directly. The LuxZeplin (LZ) detector is the world most sensitive liquid xenon detector with the main physics goal is to search for "weakly interacting matter particle" (WIMP) dark matter. After a successful science run 1 (SR1), science run 2 (SR2) is currently ongoing in the data collection phase.

Main objective of this project is to perform an effective field theory (EFT) analysis of SR2 data: extending the search region out to higher recoil energies than standard low energy WIMP search. This is motivated by the fact the several more complex dark matter interaction models are expected to occur at higher energies. The result will be either the discovery of a new dark matter candidate particle, or the setting of world leading limits on EFT coupling parameters.

In addition to the main analysis task, several other contributions will be made including: upgrading the currently analysis pipeline to use more modern computational architectures, especially GPU clusters; improving simulations which in turn will improve background discrimination; improvement of current background models - likely with the use of machine learning.

The project falls within the STFC Particle Astrophysics research area supporting question C4 - "What is the nature of Dark Matter and Dark Energy?". The research is performed as part of the LuxZeplin Collaboration.