Low-mass extension of direct detection bounds on WIMP-quark and WIMP-gluon effective interactions using the Migdal effect

TL;DR

This paper extends direct detection bounds on low-mass WIMPs by incorporating the Migdal effect, analyzing data from multiple experiments to constrain effective operators up to dimension 7.

Contribution

It introduces the use of the Migdal effect to improve low-mass WIMP detection bounds within an effective field theory framework, including data from four major experiments.

Findings

Bounds reach down to WIMP masses of about 20 MeV

Higher-dimension operators may have constraints inconsistent with effective theory validity

Analysis extends previous elastic recoil studies to include the Migdal effect

Abstract

Updating a previous analysis where we used elastic nuclear recoils we study the Migdal effect to extend to low WIMP masses the direct detection bounds to operators up to dimension 7 of the relativistic effective field theory describing WIMP interactions with quarks and gluons. To this aim we include in our analysis the data of the XENON1T, SuperCDMS, COSINE-100, and DarkSide-50 experiments and assume a standard Maxwellian for the WIMP velocity distribution. We find that the bounds can reach down to a WIMP mass $\simeq$20 MeV, although in the case of higher-dimension operators the energy scale of the ensuing constraints may be inconsistent with the validity of the effective theory.