First Constraints on WIMP-Nucleon Effective Field Theory Couplings in an Extended Energy Region From LUX-ZEPLIN

TL;DR

This paper presents the first experimental constraints on WIMP-nucleon interactions within an extended energy range, using LUX-ZEPLIN data to set limits on various effective field theory couplings without observing any excess events.

Contribution

It provides the initial model-independent limits on WIMP-nucleon effective field theory couplings over an expanded energy region from the LZ experiment data.

Findings

No significant excess observed in the extended energy region.

90% confidence level exclusion limits set on WIMP-nucleon couplings.

Extended energy analysis improves sensitivity to WIMP interactions.

Abstract

Following the first science results of the LUX-ZEPLIN (LZ) experiment, a dual-phase xenon time projection chamber operating from the Sanford Underground Research Facility in Lead, South Dakota, USA, we report the initial limits on a model-independent non-relativistic effective field theory describing the complete set of possible interactions of a weakly interacting massive particle (WIMP) with a nucleon. These results utilize the same 5.5 t fiducial mass and 60 live days of exposure collected for the LZ spin-independent and spin-dependent analyses while extending the upper limit of the energy region of interest by a factor of 7.5 to 270 keVnr. No significant excess in this high energy region is observed. Using a profile-likelihood ratio analysis, we report 90% confidence level exclusion limits on the coupling of each individual non-relativistic WIMP-nucleon operator for both elastic and inelastic interactions in the isoscalar and isovector bases.