Dark Matter Results from 225 Live Days of XENON100 Data

TL;DR

This paper reports on a dark matter search using the XENON100 detector over 13 months, setting new limits on WIMP-nucleon interactions with no confirmed detections.

Contribution

It provides the most stringent limits to date on spin-independent WIMP-nucleon cross sections for WIMP masses above 8 GeV/c^2, based on 224.6 live days of data.

Findings

No evidence of dark matter interactions was observed.

Two candidate events were consistent with background expectations.

The experiment set the most restrictive upper limits on WIMP cross sections to date.

Abstract

We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso (LNGS) for 13 months during 2011 and 2012. XENON100 features an ultra-low electromagnetic background of (5.3 \pm 0.6) \times 10^-3 events (kg day keVee)^-1 in the energy region of interest. A blind analysis of 224.6 live days \times 34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the pre-defined nuclear recoil energy range of 6.6-30.5 keVnr are consistent with the background expectation of (1.0 \pm 0.2) events. A Profile Likelihood analysis using a 6.6-43.3 keVnr energy range sets the most stringent limit on the spin-independent elastic WIMP-nucleon scattering cross section for WIMP masses above 8 GeV/c^2, with a minimum of 2 \times 10^-45 cm^2 at 55 GeV/c^2 and 90% confidence level.