Implications on inelastic dark matter from 100 live days of XENON100 data

The XENON100 experiment has completed a dark matter search with 100.9 live days of data, taken from January to June 2010. Events with energies between 8.4 and $44.6{\mathrm{keV}}_{\mathrm{nr}}$ in a fiducial volume containing 48 kg of liquid xenon have been analyzed. A total of three events have been found in the predefined signal region, compatible with the background prediction of ($1.8\pm 0.6$) events. Based on this analysis we present limits on the WIMP-nucleon cross section for inelastic dark matter. With the present data we are able to rule out the explanation for the observed DAMA/LIBRA modulation as being due to inelastic dark matter scattering off iodine, at a 90% confidence level.

Figure 1

Expected iDM nuclear recoil spectrum in XENON100 for 100.9 live days measured between January and June for a WIMP with $M_{\chi }=50\mathrm{GeV}$, $\delta =110\mathrm{keV}$ (black, solid); $M_{\chi }=55\mathrm{GeV}$, $\delta =115\mathrm{keV}$ (blue, dotted), and $M_{\chi }=60\mathrm{GeV}$, $\delta =120\mathrm{keV}$ (green, dashed) and a $\sigma$ corresponding to the lower 90% confidence limit of the DAMA/LIBRA signal. The XENON100 observed spectrum is shown in red. Vertical dotted lines show the analysis energy interval.

Figure 2

DAMA/LIBRA 90% confidence level signal region for $\delta =120\mathrm{keV}$ (gray region). Superimposed are the 90% confidence level exclusion curves for XENON100 (black, solid), CDMS [14] (red, dashed) and ZEPLIN-III [18] (blue, dash-dotted). The whole DAMA/LIBRA WIMP region is excluded by XENON100.

Figure 3

Parameter space to explain the DAMA/LIBRA annual modulation with iDM (light blue area), and parameter space excluded by the CDMS-II [14] experiment (blue horizontal lines), the ZEPLIN-III [18] experiment (green descending lines). XENON100 (red ascending lines) excludes the whole allowed DAMA/LIBRA region. The orange region corresponds to the parameter space which is not accessible to any xenon experiment. $v_0=220\mathrm{km}/\mathrm{s}$ and $v_{\mathrm{esc}}=544\mathrm{km}/\mathrm{s}$ have been assumed.