In this study the ILC's capabilities for detecting WIMPs and measure their properties are investigated. The signal events are detected by associated production of Initial State Radiation (ISR). A model independent formulation of the signal cross section is used. The cross section is normalized by inference from the observed abundance of cosmological Dark Matter (DM). The study is performed in full simulation of the ILD00 detector model. The prospects of determining the WIMP parameters individually and simultaneously are presented.
The prospects of measuring the parameters of WIMP dark matter in a model independent way at the International Linear Collider are investigated. The signal under study is direct WIMP pair production with associated initial state radiation. The analysis is performed in full simulation of the ILD detector concept. With an integrated luminosity of L = 500 fb-1 and realistic beam polarizations the helicity structure of the WIMP couplings to electrons can be determined, and the masses and cross sections can be measured to the percent level. The systematic uncertainties are dominated by the polarizat…
Although the LHC experiments have searched for and excluded many proposed new particles up to masses close to 1 TeV, there are many scenarios that are difficult to address at a hadron collider. This talk will review a number of these scenarios and present the expectations for searches at an electron-positron collider such as the International Linear Collider. The cases discussed include the light Higgsino, the stau lepton in the coannihilation region relevant to dark matter, and heavy vector bosons coupling to the s-channel in e$^+$e$^-$ annihilation. The studies are based on the ILD concept a…
In this note the ILC's capabilities for detecting WIMPs and measuring their properties are studied. The expected signal cross section is derived in a model-independent way from the observed relic density of Dark Matter. Signal events are detected by means of initial state radiation (ISR). The study is performed with a full simulation of the ILD detector. The results show that WIMPs are observable at the ILC if their coupling to electrons is not too small (O(0.1)). Their masses can be measured with a precision of 1 to 2 GeV. The accessible phase space can be increased significantly using polari…
We investigate the possibility to detect WIMPs at the ILC in a model-independent way using events with single photons. The study is done with a full detector simulation of the LDC detector and MarlinReco. It turns out that WIMPs are observable this way at the ILC if their coupling to electrons is not too small. Beam polarisation can increase the accessible phase space significantly.
WIMPs and axions are the two best motivated candidates to compose the Dark Matter of the Universe. An important number of experimental groups are developing and using different techniques for their direct detection. An updated review of current searches is done, emphasizing latest results
The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at Boulby mine (UK) is described. The detector consists of an array of encapsulated and unencapsulated NaI(Tl) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them (10.6 kg x year exposure) have been used to set upper limits on the WIMP-nucleon spin-independent and WIMP-proton spin-dependent cross-sections. Pulse shape analysis has been applied to discriminate between nuclear recoils, as may be caused by WIMP interactions, and electron recoils due to gamma backgro…
We consider analysis targets at the International Linear Collider in which only a single photon can be observed. For such processes, we have developed a method which uses likelihood distributions using the full event information (photon energy and angle). The method was applied to a search for neutralino pair production with a photon from initial state radiation (ISR) in the case of supergravity in which the neutralino is the lightest supersymmetric particle. We determine the cross section required to observe the neutralino pair production with ISR as a function of the neutralino mass in the r…
Weakly Interacting Massive Particles (WIMPs, $χ$) are candidates for Dark Matter. WIMP searches at lepton colliders are complementary to searches at hadron colliders and direct and indirect detection, since they directly probe the coupling to electrons which a priori is independent of the coupling to hadrons. Like at hadron colliders, WIMP pair production can be observed via an additional tag particle, in particular a photon from initial state radiation ($e^+e^-\rightarrowχχγ$). With this technique WIMP masses to nearly half the centre-of-mass energy can be probed. Polarised beams are essentia…
The report describes the research program on the development of ultra-low-energy germanium detectors, with emphasis on WIMP dark matter searches. A threshold of 100 eV is achieved with a 20 g detector array, providing a unique probe to the low-mas WIMP. Present data at a surface laboratory is expected to give rise to comparable sensitivities with the existing limits at the $\rm{5 - 10 GeV}$ WIMP-mass range. The projected parameter space to be probed with a full-scale, kilogram mass-range experiment is presented. Such a detector would also allow the studies of neutrino-nucleus coherent scatteri…
We report a study of CsI(Tl) scintillator to assess its applicability in experiments to search for dark matter particles. Measurements of the mean scintillation pulse shapes due to nuclear and electron recoils have been performed. We find that, as with NaI(Tl), pulse shape analysis can be used to discriminate between electron and nuclear recoils down to 4 keV. However, the discrimination factor is typically (10-15)% better than in NaI(Tl) above 4 keV. The quenching factor for caesium and iodine recoils was measured and found to increase from 11% to ~17% with decreasing recoil energy from 60 to…
An overview of the main strategies followed in the search for non-baryonic particle dark matter in the form of WIMPs is given. To illustrate these searches the case for Germanium ionization detectors is selected.
In this study, the sensitivity of future lepton colliders to WIMP dark matter is evaluated assuming WIMP pair production accompanied by a photon from initial state radiation, through which the process can be identified. A full detector simulation for the International Large Detector (ILD) concept at the International Linear Collider (ILC) is performed for a \com energy of 500\,GeV. Energy scales of up to $3$\,TeV can be tested for different effective operators for WIMP masses almost up to half the \com energy. The sensitivity benefits from the polarised beams, which can reduce the main SM back…
The p-type point-contact germanium detectors are novel techniques offering kg-scale radiation sensors with sub-keV sensitivities. They have been used for light Dark Matter WIMPs searches and may have potential applications in neutrino physics. There are, however, anomalous surface behaviour which needs to be characterized and understood. We describe the methods and results of a research program whose goals are to identify the bulk and surface events via software pulse shape analysis techniques, and to devise calibration schemes to evaluate the selection efficiency factors. Efficiencies-correct…
Weakly Interacting Massive Particles (WIMPs) are among the best-motivated dark matter candidates. In light of no conclusive detection signal yet despite an extensive search program that combines, often in a complementary way, direct, indirect, and collider probes, we find it timely to give a broad overview of the WIMP paradigm. In particular, we review here the theoretical foundations of the WIMP paradigm, discuss status and prospects of various detection strategies, and explore future experimental challenges and opportunities.
Taking liquid xenon detectors as a case study, the importance of a robust recoil energy calibration as a prerequisite to a search for light-mass Weakly Interacting Massive Particles (WIMPs) is emphasized. Important shortfalls in the analysis of existing measurements of the relative scintillation efficiency and ionization yield for nuclear recoils in liquid xenon are described, leading to the conclusion that recent attempts to extract light-WIMP sensitivity limits from the XENON10 and XENON100 detectors are premature and overly optimistic.
The status and plans of a research program on the development of ultra-low-energy germanium detectors with sub-keV sensitivities are reported. We survey the scientific goals which include the observation of neutrino-nucleus coherent scattering, the studies of neutrino magnetic moments, as well as the searches of WIMP dark matter. In particular, a threshold of 100-200 eV and a sub-keV background comparable to underground experiments were achieved with prototype detectors. New limits were set for WIMPs with mass between 3-6 GeV. The prospects of the realization of full-scale experiments are disc…
We examine a real electroweak triplet scalar field as dark matter, abandoning the requirement that its relic abundance is determined through freeze out in a standard cosmological history (a situation which we refer to as a 'miracle-less WIMP'). We extract the bounds on such a particle from collider searches, searches for direct scattering with terrestrial targets, and searches for the indirect products of annihilation. Each type of search provides complementary information, and each is most effective in a different region of parameter space. LHC searches tend to be highly dependent on the mass…
We present work on the detection of neutral particles via nuclear recoils in gas-filled Time Projection Chambers (TPCs). We employ Gas Electron Multipliers (GEMs) to amplify the signal and silicon pixel electronics to detect the avalanche charge. These technologies allow ionization in the target gas to be detected with low noise, improved position and time resolution, and high efficiency. We review experimental results obtained in previous years, and report on ongoing simulation studies and construction of the first prototype at the University of Hawaii. We also present prospects of using such…
The predictions of our previous analyses about possible low-mass (lower than 50 GeV) relic neutralinos are discussed in the light of the most recent results from WIMP direct detection experiments. It is proved that these light neutralinos are quite compatible with the new annual-modulation data of the DAMA Collaboration; our theoretical predictions are also compared with the upper bounds of the CDMS and EDELWEISS Collaborations.
SIMPLE (Superheated Instrument for Massive ParticLE searches) employs superheated droplet detectors (SDDs) to search for Weakly Interacting Massive Particle (WIMP) dark matter. As a result of the intrinsic SDD insensitivity to minimum ionizing particles and high fluorine content of target liquids, competitive WIMP limits were already obtained at the early prototype stage. We comment here on the expected immediate increase in sensitivity of the program and on future plans to exploit this promising technnique.
Plots summarizing the constraints on Dark Matter models can help visualize synergies between different searches for the same kind of experiment, as well as between different experiments. In this whitepaper, we present an update to the European Strategy Briefing Book plots, from the perspective of collider searches within the Dark Matter at the Energy Frontier (EF10) Snowmass Topical Group, starting from inputs from future collider facilities. We take as a starting point the plots currently made for LHC searches using benchmark models recommended by the Dark Matter Working Group, also used for …
We report here on the results from the Weakly Interacting Massive Particle (WIMP) search with the LUX dark matter experiment. LUX, a two-phase xenon time projection chamber (TPC) with 250 kg of active mass, has been operated from 2012 until 2016. During the operation, we observed no evidence for WIMP elastic scattering events. LUX achieved the most stringent limit on both the WIMP-nucleon spin-independent cross section (1.1$\times{10}^{-46}$ cm$^2$ for a 50 GeV/c${}^{2}$, 90% C.L.) and on the WIMP-neutron spin-dependent cross section (1.6$\times{10}^{-41}$ cm$^2$ for a 35 GeV/c${}^{2}$, 90% C.…
A well-known potential dark matter signature is emission of GeV - TeV neutrinos from annihilation of neutralinos gravitationally bound to massive objects. We present results from recent searches for high energy neutrino emission from the Sun with AMANDA, in all cases revealing no significant excess. We show limits on both neutralino-induced muon flux from the Sun and neutralino-nucleon cross section, comparing them with recent IceCube results. Particularly, our limits on spin-dependent cross section are much better than those obtained in direct detection experiments, allowing AMANDA and other …
The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at the Boulby Underground Laboratory (North Yorkshire, UK) ran from 2000 until 2003. A total of 44.9 kg x years of data collected with 2 encapsulated and 4 unencapsulated NaI(Tl) crystals with high light yield were included in the analysis. We present final results of this analysis carried out using pulse shape discrimination. No signal associated with nuclear recoils from WIMP interactions was observed in any run with any crystal. This allowed us to set upper limits on the WIMP-nucleon spin-independent and WIMP-proton …
A potential source of high energy neutrinos is the annihilation of Weakly Interacting Massive Particles (WIMPs) collecting in gravitational potential wells such as the centers of the Earth, the Sun, or the Galaxy. A search for such a WIMP annihilation signal using the Super-Kamiokande (Super-K) detector is presented. Super-K observes 1.1 upward through-going muons per day. These events are caused by high energy (typical E_nu ~ 100 GeV) nu_mu interactions in the rock under the detector, and are generally consistent with the expected flux from atmospheric neutrinos. No enhancement of the neutrin…
The SuperCDMS experiment searches for weakly interacting massive particles (WIMPs) using cryogenic germanium detectors that measure ionization and phonon energy. Several direct searches for WIMPs have recently reported excesses of events above their background expectations, which could be interpreted as WIMPs with masses in the 8-20 GeV/c^2 range. The excellent intrinsic signal-to-noise of SuperCDMS detectors and their powerful background rejection make SuperCDMS an ideal experiment to further test these signal hints. We present the results of two recent SuperCDMS analyses targeting this mass …
We study the prospects of detecting muon events at the upcoming Iron CALorimeter (ICAL) detector to be built at the proposed India-based Neutrino Observatory (INO) facility due to neutrinos arising out of annihilation of Weakly Interactive Massive Particles (WIMP) in the centre of the earth. The atmospheric neutrinos coming from the direction of earth core presents an irreducible background. We consider 50kt $\times$ 10 years of ICAL running and WIMP masses between 10-100 GeV and present 90 \% C.L. exclusion sensitivity limits on $σ_{SI}$ which is the WIMP-nucleon Spin Independent (SI) interac…
The current state searches for dark matter in the form of Weakly Interacting Massive Particles (WIMPs) using both direct and indirect techniques is reviewed. Advances in recent years by various direct search experiments, utilising technology able to record the nuclear recoil events expected from elastic scattering by WIMPs, have allowed progress towards lower limits to be made. In particular, the Edelweiss and CDMS collaborations are achieving sensitiviy able to challenge data from DAMA interpreted as evidence for WIMPs of mass in the region of 60 GeV. Meanwhile, indirect searches, based on ob…
Cosmological observations and the dynamics of the Milky Way provide ample evidence for an invisible and dominant mass component. This so-called dark matter could be made of new, colour and charge neutral particles, which were non-relativistic when they decoupled from ordinary matter in the early universe. Such weakly interacting massive particles (WIMPs) are predicted to have a non-zero coupling to baryons and could be detected via their collisions with atomic nuclei in ultra-low background, deep underground detectors. Among these, detectors based on liquefied noble gases have demonstrated tre…
We propose a method using solid state detectors with directional sensitivity to dark matter interactions to detect low-mass Weakly Interacting Massive Particles (WIMPs) originating from galactic sources. In spite of a large body of literature for high-mass WIMP detectors with directional sensitivity, no available technique exists to cover WIMPs in the mass range <1 GeV. We argue that single-electron resolution semiconductor detectors allow for directional sensitivity once properly calibrated. We examine commonly used semiconductor material response to these low-mass WIMP interactions.
A proposal submitted to the FNAL PAC is described to search for light sub-GeV WIMP dark matter at MiniBooNE. The possibility to steer the beam past the target and into an absorber leads to a significant reduction in neutrino background, allowing for a sensitive search for elastic scattering of WIMPs off nucleons or electrons in the detector. Dark matter models involving a vector mediator can be probed in a parameter region consistent with the required thermal relic density, and which overlaps the region in which these models can resolve the muon g-2 discrepancy. Estimates of signal significanc…
Although the LHC experiments have searched for and excluded many proposed new particles up to masses close to 1 TeV, there are many scenarios that are difficult to address at a hadron collider. This talk will review a number of these scenarios and present the expectations for searches at an electron-positron collider such as the International Linear Collider. The cases discussed include the light Higgsino, the \stau~ slepton in the coannihilation region relevant to dark matter, as well as other SUSY signatures. he studies are based on the ILD concept at the ILC.
Although the LHC experiments have searched for and excluded many proposed new particles up to masses close to 1 TeV, there are many scenarios that are difficult to address at a hadron collider. This talk will review a number of these scenarios and present the expectations for searches at an electron-positron collider such as the International Linear Collider. The cases discussed include the light Higgsino, the \stau~ slepton in the coannihilation region relevant to dark matter, as well as other BSM signatures. The studies are based on the ILD concept at the ILC.
The combination of S-matrix unitarity and the dynamics of thermal freeze-out for massive relic particles (denoted here simply by WIMPs) implies a lower limit on the density of such particles, that provide a (potentially sub-dominant) contribution to dark matter. This then translates to lower limits to the signal rates for a variety of techniques for direct and indirect detection of dark matter. For illustration, we focus on models where annihilation is s-wave dominated. We derive lower limits to the flux of gamma-rays from WIMP annihilation at the Galactic center; direct detection of WIMPs; en…
SIMPLE 2000 (Superheated Instrument for Massive ParticLE searches) will consist of an array of eight to sixteen large active mass ($\sim15$ g) Superheated Droplet Detectors(SDDs) to be installed in the new underground laboratory of Rustrel-Pays d'Apt. Several factors make of SDDs an attractive approach for the detection of Weakly Interacting Massive Particles (WIMPs), namely their intrinsic insensitivity to minimum ionizing particles, high fluorine content, low cost and operation near ambient pressure and temperature. We comment here on the fabrication, calibration and already-competitive firs…
We present extrapolations of the current mono-jet searches at the LHC to potential future hadron collider facilities: LHC14, as well as $pp$ colliders with $\sqrt{s}=33$ or 100 TeV. We consider both the effective operator approach as well as one example of a light mediating particle.
The standard model (SM) plus a real gauge-singlet scalar field dubbed darkon (SM+D) is the simplest model possessing a weakly interacting massive particle (WIMP) dark-matter candidate. The upper limits for the WIMP-nucleon elastic cross-section as a function of WIMP mass from the recent XENON10 and CDMS-II experiments rule out darkon mass ranges from 10 to (50,70,75) GeV for Higgs-boson masses of (120,200,350) GeV, respectively. This may exclude the possibility of the darkon providing an explanation for the gamma-ray excess observed in the EGRET data. We show that by extending the SM+D to a tw…
Weakly Interacting Massive Particles (WIMPs), are a leading candidate for the dark matter that is observed to constitute ~25% of the total mass-energy density of the Universe. The direct detection of relic WIMPs (those produced during the early moments of the Universe's expansion) is at the forefront of active research areas in particle astrophysics with a numerous international experimental collaborations pursuing this goal. This paper presents an overview of the theoretical and practical considerations common to the design and operation of direct detection experiments, as well as their uniqu…
Understanding the ability to measure and discriminate particle events at the lowest possible energy is an essential requirement in developing new experiments to search for weakly interacting massive particle (WIMP) dark matter. In this paper we detail an assessment of the potential sensitivity below 10 keV in the 1 m^3 DRIFT-II directionally sensitive, low pressure, negative ion time projection chamber (NITPC), based on event-by-event track reconstruction and calorimetry in the multiwire proportional chamber (MWPC) readout. By application of a digital smoothing polynomial it is shown that the …
The annihilation of Weakly Interactive Massive Particles (WIMP) in the centre of the sun could give rise to neutrino fluxes. We study the prospects of searching for these neutrinos at the upcoming Iron CALorimeter (ICAL) detector to be housed at the India-based Neutrino Observatory (INO). We perform ICAL simulations to obtain the detector efficiencies and resolutions in order to simulate muon events in ICAL due to neutrinos coming from annihilation of WIMP in the mass range $m_χ= (3-100)$ GeV. The atmospheric neutrinos pose a major background for these indirect detection studies and can be red…
We propose a formalism for the analysis of direct-detection dark-matter searches that covers all coherent responses for scalar and vector interactions and incorporates QCD constraints imposed by chiral symmetry, including all one- and two-body WIMP-nucleon interactions up to third order in chiral effective field theory. One of the free parameters in the WIMP-nucleus cross section corresponds to standard spin-independent searches, but in general different combinations of new-physics couplings are probed. We identify the interference with the isovector counterpart of the standard spin-independen…
Dark Matter is a hypothetical particle proposed to explain the missing matter expected from the cosmological observation. The motivation of Dark Matter is overwhelming however as it is mainly deduced from its gravitational interaction, for it does little to pinpoint what Dark Matter really is. In WIMPs Miracle, weakly interactive massive particle being the Dark Matter candidate is correctly producing the current thermal relic density at weak scale, implying the possibility of producing and detecting it in Large Hadron Collider. Assuming WIMPs being the maverick particle within collider, it is …
The main characteristics of a new concept of spherical gaseous detectors, with some details on its operation are first given. The very low energy threshold of such detector has led to investigations of its potential performance for dark matter particle searches, in particular low mass WIMP's : original methods for energy and fiducial volume calibration and background rejection are described and preliminary results obtained with a low radioactivity prototype operated in Laboratoire Souterrain de Modane ("Frejus" lab) are presented. Typical expected sensitivities in cross section for low mass WI…
We present a novel analysis technique for liquid xenon time projection chambers that allows for a lower threshold by relying on events with a prompt scintillation signal consisting of single detected photons. The energy threshold of the LUX dark matter experiment is primarily determined by the smallest scintillation response detectable, which previously required a 2-fold coincidence signal in its photomultiplier arrays, enforced in data analysis. The technique presented here exploits the double photoelectron emission effect observed in some photomultiplier models at vacuum ultraviolet waveleng…
