A search for light dark matter in XENON10 data

TL;DR

The data strongly constrain recent elastic dark matter interpretations of excess low-energy events observed by CoGeNT and CRESST-II, as well as the DAMA annual modulation signal.

Abstract

We report results of a search for light (<10 GeV) particle dark matter with the XENON10 detector. The event trigger was sensitive to a single electron, with the analysis threshold of 5 electrons corresponding to 1.4 keV nuclear recoil energy. Considering spin-independent dark matter-nucleon scattering, we exclude cross sections σ_n>3.5x10^{-42} cm^2, for a dark matter particle mass m_χ=8 GeV. We find that our data strongly constrain recent elastic dark matter interpretations of excess low-energy events observed by CoGeNT and CRESST-II, as well as the DAMA annual modulation signal.

Figures (3)

• Figure 1: The electron yield $\mathcal{Q}_y$ of liquid xenon for nuclear recoils. Theoretical curves (solid and dashed) were calculated from Eq. \ref{['eq1']}, as described in the text. Also shown are measurements from 2010manzur ($\bigstar$), 2010sorensen_idm (dash-dot curve, with $\pm1\sigma$ contours) and 2006aprile ($\fullmoon$ and $\blacksquare$, uncertainty omitted for clarity).
• Figure 2: (left) All candidate dark matter events remaining ($\times$ and $\fullmoon$) after the cuts listed in Table \ref{['table1']}. Events in which an S1 was found are shown as $\fullmoon$. The number of electrons in the S2 signal is indicated by the inset scale. (top) Distribution of candidate events with $\leq4$ electrons ($+$), and distribution of background single electrons ($\triangle$) as described in the text. (right) S2 pulse width distributions for single scatter nuclear recoils in the top, middle and bottom third of the detector.
• Figure 3: Curves indicate 90% C.L. exclusion limits on spin-independent $\sigma_n$ for elastic dark matter scattering, obtained by CDMS (dotted 2010akerib, and dashed 2010ahmed) and XENON100 (dash-dot 2010aprile100). The region consistent with assumption of a positive detection by CoGeNT is shown (hatched) 2010aalseth, and (shaded) 2010chang3; the latter assumes a 30% exponential background. Also shown is the $3\sigma$ allowed region for the DAMA annual modulation signal (solid contour) 2011savage.