Complementarity of dark matter direct detection: the role of bolometric targets

Abstract

We study how the combined observation of dark matter in various direct detection experiments can be used to determine the phenomenological properties of WIMP dark matter: mass, spin-dependent (SD) and spin-independent (SI) scattering cross section off nucleons. A convenient choice of target materials, including nuclei that couple to dark matter particles through a significantly different ratio of SD vs SI interactions, could break the degeneracies in the determination of those parameters that a single experiment cannot discriminate. In this work we investigate different targets that can be used as scintillating bolometers and could provide complementary information to germanium and xenon detectors. We observe that Al 2 O 3 and LiF bolometers could allow a good reconstruction of the DM properties over regions of the parameter space with a SD scattering cross section as small as 10 −5 pb and a SI cross section as small as 5 × 10 −10 pb for a 50 GeV WIMP. In the case of a CaWO 4 bolometer the area in which full complementarity is obtained is smaller but we show that it can be used to determine the WIMP mass and its SI cross section. For each target we study the required exposure and background.a MultiDark Scholar b MultiDark Fellow

Scintillating bolometers: A key for determining WIMP parameters

“…As we showed in Ref. 24, the combination of data from Ge and Xe leads to a substantial reduction in the contours of the reconstructed WIMP parameters. The improved energy threshold also contributes to this.…”

“…As in our previous paper, 24 we start the analysis studying the complementarity of two experiments, based, respectively on Ge and Xe. Such elements are employed by the collaborations producing the currently most stringent limits on WIMP properties and are contemplated in projects planning to extend the search to the ton scale (e.g.…”

“…Such degeneracy can be broken by including more targets in the analysis: in Ref. 24 we defined "complementarity" as the situation in which a certain set of experiments manages to determine m χ , σ SI and σ SD with a certain finite accuracy, or, equivalently, when 68% confidence level of the 2-dimensional contours are closed simultaneously in the three planes (m χ , σ SI ), (m χ , σ SD ) and (σ SI , σ SD ).…”

“…Signals from different targets are needed, since they can provide complementary information which can lead to a better determination of the DM parameters. 22,23 In a previous paper 24 we analysed the complementarity of a Ge and a Xe experiment with energy thresholds and resolutions already achieved by CDMS and XENON100 experiments, respectively, and with background levels expected for their corresponding extensions (SuperCDMS 25 and XENON1T 26 ). For different WIMP scenarios, we assumed hypothetical detections with an exposure of 300 kg×yr in both experiments and we concluded that the combination of data from Xe and Ge-based detectors might not lead to a good reconstruction of all the WIMP parameters, since there is a degeneracy in the SI and SD parts of the scattering WIMP-nucleus cross section, and both targets have very similar SI over SD sensitivity (see also Ref.…”

Dark matter effective field theory scattering in direct detection experiments

“…Previous work has shown that complementary target elements can break the degeneracy between the standard spindependent and spin-independent operators [32,33], and others have shown that this concept can also be applied to the larger EFT parameter space [28]. Such considerations are particularly important when incorporating the effect of interference on the event rate.…”