Direct dark matter search by annual modulation in XMASS-I

Abstract

A search for dark matter was conducted by looking for an annual modulation signal due to the Earth's rotation around the Sun using XMASS, a single phase liquid xenon detector. The data used for this analysis was 359.2 live days times 832 kg of exposure accumulated between November 2013 and March 2015. When we assume Weakly Interacting Massive Particle (WIMP) dark matter elastically scattering on the target nuclei, the exclusion upper limit of the WIMP-nucleon cross section 4.3×10 −41 cm 2 at 8 GeV/c 2 was obtained and we exclude almost all the DAMA/LIBRA allowed region in the 6 to 16 GeV/c 2 range at ∼10 −40 cm 2 . The result of a simple modulation analysis, without assuming any specific dark matter model but including electron/γ events, showed a slight negative amplitude. The p-values obtained with two independent analyses are 0.014 and 0.068 for null hypothesis, respectively. we obtained 90% C.L. upper bounds that can be used to test various models. This is the first extensive annual modulation search probing this region with an exposure comparable to DAMA/LIBRA.

Low energy analysis techniques for CUORE

“…Thanks to the 741 kg of target mass of CUORE, we expect to achieve the sensitivity required to fully explore the parameter region implied by the DAMA/LIBRA posi-tive annual modulation signal with 5 years of data-taking. Other recent experimental results from CRESST-II, CDMS Lite, XMASS and LUX [32][33][34][35] are also shown. The results from CRESST-II, CDMS, and LUX were obtained using v esc = 544 km/s.…”

“…DAMA/LIBRA positive signal reported in [31] is shown as yellow/dark yellow/orange islands. The results from CRESST-II (dashed green) [32], CDMS Lite (dashed red) [33], XMASS (dashed violet) [34], and LUX (black solid) [35] are also shown ity assuming the same background rate and energy thresholds. This is a conservative hypothesis since a significant background reduction is expected to be achieved in CUORE thanks to its close-packed detector configuration and the careful selection of radio-pure detector materials [25].…”

Direct detection of WIMP dark matter: concepts and status

“…These experiments are sensitive to the energy interval in which DAMA observes its signal, have a significantly lower background and were operated stably for several years. The electronic structures of xenon and iodine are very similar and the non-observation of a modulation signal thus allowed XENON100, XMASS and LUX to exclude the DAMA signal at 5.7 σ, ∼2 σ and 9.2 σ, respectively [118,119,120].…”

Status of Dark Matter Searches (Rapporteur Talk)

“…The observed annual modulation is inconsistent with indirect and other direct detection bounds, however different target materials have been used. Results of a search for an annual modulation in XMASS-I [92,93] are shown in figure 17 as an example. Four efforts are now underway to search for the annual modulation using the same NaI target material as used by DAMA/LIBRA: ( The COSINE experiment was extensively discussed at ICRC and has already started its physics data run.…”