Halo-independent methods for inelastic dark matter scattering

Bozorgnia, Nassim; Herrero-García, Juan; Schwetz, Thomas; Zupan, Jure

doi:10.1088/1475-7516/2013/07/049

Cited by 58 publications

(79 citation statements)

References 42 publications

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“…On the assumption that there is no dark form factor, the event distributions (once we have compensated for the different target nuclei) with respect to v min should be the same for each of the experiments [26][27][28][29][30][31] -any disagreement indicates the presence of some extra effect. For a dark form factor, since q(v min ) = 2µ XN v min , changing µ XN by changing m N will change the range of F X (q) that we sample (significantly so if the DM mass is larger than those of the SM target nuclei).…”

Section: Jhep07(2015)133mentioning

confidence: 99%

Signatures of large composite Dark Matter states

Hardy

Lasenby

March-Russell

et al. 2015

J. High Energ. Phys.

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Abstract:We investigate the interactions of large composite dark matter (DM) states with the Standard Model (SM) sector. Elastic scattering with SM nuclei can be coherently enhanced by factors as large as A 2 , where A is the number of constituents in the composite state (there exist models in which DM states of very large A 10 8 may be realised). This enhancement, for a given direct detection event rate, weakens the expected signals at colliders by up to 1/A. Moreover, the spatially extended nature of the DM states leads to an additional, characteristic, form factor modifying the momentum dependence of scattering processes, altering the recoil energy spectra in direct detection experiments. In particular, energy recoil spectra with peaks and troughs are possible, and such features could be confirmed with only O(50) events, independently of the assumed halo velocity distribution. Large composite states also generically give rise to low-energy collective excitations potentially relevant to direct detection and indirect detection phenomenology. We compute the form factor for a generic class of such excitations -quantised surface modes -finding that they can lead to coherently-enhanced, but generally sub-dominant, inelastic scattering in direct detection experiments. Finally, we study the modifications to capture rates in astrophysical objects that follow from the elastic form factor, as well as the effects of inelastic interactions between DM states once captured. We argue that inelastic interactions may lead to the DM collapsing to a dense configuration at the centre of the object.

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Section: Jhep07(2015)133mentioning

confidence: 99%

Signatures of large composite Dark Matter states

Hardy

Lasenby

March-Russell

et al. 2015

J. High Energ. Phys.

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“…In the absence of unknown form factors, all experimental data can be mapped into v minspace at each DM mass and compared without specifying the nature of the astrophysical distribution or density of DM [39,40]. These "halo-independent" methods have received significant attention [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. We generalize these methods to cover relativistic scattering as well, where the "halo-independence" here comes from the absence of specific assumptions regarding the local DM density, density profile, velocity distribution, and annihilation source.…”

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confidence: 99%

Direct Detection Phenomenology in Models Where the Products of Dark Matter Annihilation Interact with Nuclei

2015

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We investigate the direct detection phenomenology of a class of dark matter (DM) models in which DM does not directly interact with nuclei, but rather the products of its annihilation do. When these annihilation products are very light compared to the DM mass, the scattering in direct detection experiments is controlled by relativistic kinematics. This results in a distinctive recoil spectrum, a non-standard and or even absent annual modulation, and the ability to probe DM masses as low as a ∼10 MeV. We use current LUX data to show that experimental sensitivity to thermal relic annihilation cross sections has already been reached in a class of models. Moreover, the compatibility of dark matter direct detection experiments can be compared directly in Emin space without making assumptions about DM astrophysics, mass, or scattering form factors. Lastly, when DM has direct couplings to nuclei, the limit from annihilation to relativistic particles in the Sun can be stronger than that of conventional non-relativistic direct detection by more than three orders of magnitude for masses in a 2-7 GeV window.Introduction -While very little is known about Dark Matter (DM), its cosmological abundance is experimentally quite well-determined: Ω CDM h 2 = 0.1199 ± 0.0027 [1]. An appealing framework for understanding the relic abundance of Dark Matter (DM) is thermal freeze-out [2]. Number-changing interactions in the early universe, XX ↔ (SM)SM keep DM in thermal equilibrium with the SM bath, until the rate of these annihilation processes drops below the rate of Hubble expansion. After this point the abundance of DM is essentially fixed at, Ω CDM h 2 0.12 6 × 10 −26 cm 3 s −1 / σ ann v rel , singling out a characteristic annihilation cross section σ ann v rel for thermally produced DM to yield the observed abundance. This scenario is attractive in that it provides a simple and elegant framework for the relic abundance that can be tested in a variety of ways, including direct detection (DD) [3]. However, current constraints from DD rule out many of the simplest models of thermal relic DM, which may indicate a modification of the above picture.In this paper we investigate a modification of thermal DM which alleviates the tension between DD constraints and the thermal relic hypothesis, while making unique predictions for DD. In particular, we take the abundance of DM, X, to be determined by the annihilation process XX ↔ Y Y , where Y is a much lighter dark sector species. The interactions of the dark sector state Y with ordinary nuclei allows for a unique test of the scenario at DD experiments. The resulting DD phenomenology of this class of models is distinctive, owing to the fact that (1) the scattering partner of the nucleus is relativistic, rendering the kinematics of scattering completely different and (2) it is the flux of the scattering partner Y that determines the rate of events at a detector rather than X. Both of these features have novel consequences not considered in the literature of "model-independent" direct detecti...

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“…This is the basis of the HI framework developed to compare among DD signals and limits, extended also to annual modulation signals [8,9] in refs. [10,11], and to inelastic scattering [12]. Recently in refs.…”

Section: Motivation: a New Halo-independent Frameworkmentioning

confidence: 98%

“…By extracting the halo integral η(E R ), one can check if it is compatible with the signal being due to DM, as different energy branches contribute to the same velocity range and therefore should give the same rate, see ref. [12] for this shape test. From this observed η(E R ) spectrum we can derive the minimum energy E obs min whereη(E R ) is maximal (lowest v m (E R )), and exothermic (dashed) interactions with δ = 50 (−50) keV, respectively.…”

Section: Inelastic Scattering (Exothermic and Endothermic) In Dd And mentioning

confidence: 99%

Predicting the capture rate in the Sun from a direct detection signal independently of the astrophysics

Herrero-García¹

2016

J. Phys.: Conf. Ser.

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Abstract. The goal of the works on which this talk is based is to relate a direct detection signal with neutrino limits from the Sun independently of the astrophysics. In order to achieve this we derive a halo-independent lower bound on the dark matter capture rate in the Sun from a direct detection signal, with which one can set upper limits on the branching ratios into different channels from the absence of a high-energy neutrino flux in neutrino observatories. We also extend this bound to the case of inelastic scattering, both endothermic and exothermic.From two inelastic signals we show how the dark matter mass, the mass difference of the states and the couplings to neutrons and protons can be obtained. Furthermore, one can also pin down the exothermic/endothermic nature of the scattering, and therefore a precise lower bound on the solar capture rate is predicted. We also discuss isospin violation and uncertainties due to form factors. Motivation: a new halo-independent frameworkIt is well-known that dark matter (DM) direct detection (DD) signals are very sensitive to the astrophysical uncertainties of the halo, which makes their compatibility with other results astrophysics-dependent. This talk is devoted to a new halo-independent (HI) framework to compare DD signals with upper limits from neutrino telescopes [1,2].Let us first review the basic expressions for DM DD and the well-known HI framework used for comparing among DD signals. For SI interactions, the DM event rate in underground detectors can be written as [3]where f det (v) is the (unknown) velocity distribution in the detector rest-frame, F A (E R ) is a nuclear form factor, A 2 eff = (Z + κ (A − Z)) 2 with κ = f n /f p andThe mass-splitting parameter δ appears in inelastic interactions [4], given by δ ≡ m χ * − m χ , and thus it is positive (negative) for endothermic (exothermic [5]) interactions. For δ = 0 elastic interactions are recovered. σ SI is the total DM-proton scattering cross section at zero momentum transfer, µ χp is the DM-proton reduced mass and ρ χ is the local DM mass density.

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Halo-independent methods for inelastic dark matter scattering

Cited by 58 publications

References 42 publications

Signatures of large composite Dark Matter states

Signatures of large composite Dark Matter states

Direct Detection Phenomenology in Models Where the Products of Dark Matter Annihilation Interact with Nuclei

Predicting the capture rate in the Sun from a direct detection signal independently of the astrophysics

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