Limits on inelastic dark matter from ZEPLIN-III

TL;DR

This paper sets new limits on inelastic dark matter interactions using ZEPLIN-III data, constraining the parameter space and challenging explanations of DAMA's modulation signal with xenon detectors.

Contribution

First to derive inelastic dark matter constraints from ZEPLIN-III data, tightening bounds on the parameter space and challenging DAMA's interpretation.

Findings

No significant excess events observed.

Excludes part of the parameter space consistent with DAMA.

Provides the tightest xenon-based constraints on inelastic dark matter.

Abstract

We present limits on the WIMP-nucleon cross section for inelastic dark matter derived from the 2008 run of ZEPLIN-III. Cuts, notably on scintillation pulse shape and scintillation-to-ionisation ratio, give a net exposure of 63 kg.days in the range 20-80keV nuclear recoil energy, in which 6 events are observed. Upper limits on signal rate are derived from the maximum empty patch in the data. Under standard halo assumptions a small region of parameter space consistent, at 99% CL, with causing the 1.17 ton.year DAMA modulation signal is allowed at 90% CL: it is in the mass range 45-60 GeV with a minimum CL of 88%, again derived from the maximum patch. This is the tightest constraint on that explanation of the DAMA result yet presented using a xenon target.