Direct Detection Limits Research Articles

Revisiting the decoupling limit of the Georgi-Machacek model with a scalar singlet

We study the connection between collider and dark matter phenomenology in the singlet extension of the Georgi-Machacek model. In this framework, the singlet scalar serves as a suitable thermal dark matter (DM) candidate. Our focus lies on the region vχ< 1 GeV, where vχ is the common vacuum expectation value of the neutral components of the scalar triplets of the model. Setting bounds on the model parameters from theoretical, electroweak precision and LHC experimental constraints, we find that the BSM Higgs sector is highly constrained. Allowed values for the masses of the custodial fiveplets, triplets and singlet are restricted to the range 140 GeV <MH50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {M}_{H_5^0} $$\\end{document}< 350 GeV, 150 GeV <MH30\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {M}_{H_3^0} $$\\end{document}< 270 GeV and 145 GeV < MH< 300 GeV. The extended scalar sector provides new channels for DM annihilation into BSM scalars that allow to satisfy the observed relic density constraint while being consistent with direct DM detection limits. The allowed region of the parameter space of the model can be explored in the upcoming DM detection experiments, both direct and indirect. In particular, the possible high values of BR(H50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {H}_5^0 $$\\end{document} → γγ) can lead to an indirect DM signal within the reach of CTA. The same feature also provides the possibility of exploring the model at the High-Luminosity run of the LHC. In a simple cut-based analysis, we find that a signal of about 4σ significance can be achieved in final states with at least two photons for one of our benchmark points.

Comprehensive constraints on fermionic dark matter-quark tensor interactions in direct detection experiments* *Supported in part by the Major Project of Basic and Applied Basic Research of Guangdong Province, China(2020B0301030008) and the National Natural Science Foundation of China(12035008, 12247151, 12305110, 12347121)

Effective field theory (EFT) provides a model-independent framework for interpreting the results of dark matter (DM) direct detection experiments. In this study, we demonstrate that the two fermionic DM-quark tensor operators and can contribute to the DM electric and magnetic dipole moments via nonperturbative QCD effects, in addition to the well-studied contact DM-nucleon operators. We then investigate the constraints on these two operators by considering both the contact and dipole contributions using the XENON1T nuclear recoil and Migdal effect data. We also recast other existing bounds on the DM dipole operators, derived from electron and nuclear recoil measurements in various direct detection experiments, as constraints on the two tensor operators. For , our results significantly extend the reach of constraints on the DM-quark tensor operators to masses as low as , with the bound exceeding that obtained by the Migdal effect with only contact interactions by approximately an order of magnitude. In particular, for the operator with DM mass , the latest PandaX constraint on the DM electric dipole moment puts more stringent bounds than the previous direct detection limit. We also briefly discuss the constraints obtained from experiments other than direct detection.

High-sensitivity dual-comb and cross-comb spectroscopy across the infrared using a widely tunable and free-running optical parametric oscillator

Dual-comb spectroscopy (DCS) enables high-resolution measurements at high speeds without the trade-off between resolution and update rate inherent to mechanical delay scanning. However, high complexity and limited sensitivity remain significant challenges for DCS systems. We address these via a wavelength-tunable dual-comb optical parametric oscillator (OPO) combined with an up-conversion detection method. The OPO is tunable from 1300-1670 nm (signal) and 2700-5000 nm (idler). Spatial multiplexing in both the laser and OPO cavities creates a near-common path arrangement, enabling comb-line-resolved measurements in free-running operation. The narrow instantaneous bandwidth results in high power per comb-line up to 160 μW in the mid-infrared. Through intra-cavity up-conversion based on cross-comb spectroscopy, we leverage these power levels while overcoming the sensitivity limitations of direct mid-infrared detection. This approach yields a high signal-to-noise ratio (50.2 dB Hz1/2) and high dual-comb figure of merit (3.5 × 108 Hz1/2). This scheme enabled detecting ambient methane over a 3-meter path length in millisecond time scale.

Milky Way white dwarfs as sub-GeV to multi-TeV dark matter detectors

We show that Milky Way white dwarfs are excellent targets for dark matter (DM) detection. Using Fermi and H.E.S.S. Galactic center gamma-ray data, we investigate sensitivity to DM annihilating within white dwarfs into long-lived or boosted mediators and producing detectable gamma rays. Depending on the Galactic DM distribution, we set new constraints on the spin-independent scattering cross section down to 10-45-10-41 cm2 in the sub-GeV DM mass range, which is multiple orders of magnitude stronger than existing limits. For a generalized NFW DM profile, we find that our white dwarf constraints exceed spin-independent direct detection limits across most of the sub-GeV to multi-TeV DM mass range, achieving sensitivities as low as about 10-46 cm2. In addition, we improve earlier versions of the DM capture calculation in white dwarfs, by including the low-temperature distribution of nuclei when the white dwarf approaches crystallization. This yields smaller capture rates than previously calculated by a factor of a few up to two orders of magnitude, depending on white dwarf size and the astrophysical system.

DM-SM interactions mediated by spin-one particles: EFT study

Standard model-dark matter particles, mediated by spin one fields, are analyzed within the effective field theory framework. We [1, 2] consider dark particles masses from few MeV to 6.4 TeV. We restrict the EFT using bounds from relic density, Z invisible decay width, direct and indirect detection limits and collider constraints. Solutions below mZ are found for two operators. Others, around the electroweak scale or slightly above, are also compatible with all present limits.

Soft scattering evaporation of dark matter subhalos by inner galactic gases

The large gap between a galactic dark matter subhalo’s velocity and its own gravitational binding velocity creates the situation that small subhalos can be evaporated before dark matter thermalize with baryons due to the low binding velocity. In case dark matter acquires an electromagnetic dipole moment, the survival of low-mass subhalos requires stringent limits on the photon-mediated soft scattering. The current stringent direct detection limits indicate for a small dipole moment, which lets DM decouple early and allows small subhalos to form. We calculate the DM kinetic decoupling temperature in the Early Universe and evaluate the smallest protohalo mass. In the late Universe, low-mass subhalos can be evaporated via soft collision by ionized gas and accelerated cosmic rays. We calculate the subhalos evaporation rate and show that subhalos lighter than 10^{-5}M_{odot } in the gaseous inner galactic region are subject to evaporation via dark matter’s effective electric and magnetic dipole moments below current direct detection limits, which potentially affects the low-mass subhalos distribution in the galactic center.

Direct detection of cosmic ray-boosted puffy dark matter

For the light relativistic dark matter (DM) boosted by high energy cosmic ray, its scattering cross section with the nucleon is sensitively dependent on the momentum-transfer and such an dependence is caused by the mediator in the scattering. For puffy DM particle with a size, the momentum-transfer dependence can also arise from the DM radius effect. All these momentum-transfer dependences should be considered. In this note we study the direct detection limits on the cosmic ray-boosted puffy DM for a simplified model with a light mediator. For comparison, we first re-derive the direct detection limits on the cosmic ray-boosted point-like DM. We display the limits on various planes of parameters and find that the limits for the cosmic ray-boosted puffy DM are stronger than for the point-like DM.

Resonant scattering between dark matter and baryons: Revised direct detection and CMB limits

Traditional dark matter models, e.g., weakly interacting massive particles (WIMPs), assume dark matter (DM) is weakly coupled to the standard model so that elastic scattering between dark matter and baryons can be described perturbatively by the Born approximation; most direct detection experiments are analyzed according to that assumption. We show that when the fundamental DM-baryon interaction is attractive, dark matter-nucleus scattering is nonperturbative in much of the relevant parameter range. The cross section exhibits rich resonant behavior with a highly nontrivial dependence on atomic mass; furthermore, the extended rather than pointlike nature of nuclei significantly impacts the cross sections and must therefore be properly taken into account. The repulsive case also shows significant departures from perturbative predictions and also requires full numerical calculation. These nonperturbative effects change the boundaries of exclusion regions from existing direct detection, astrophysical and CMB constraints. Near a resonance value of the parameters the typical velocity-independent Yukawa behavior, $\ensuremath{\sigma}\ensuremath{\sim}{v}^{0}$, does not apply. We take the nontrivial velocity dependence into account in our analysis, however it turns out that this more accurate treatment has little impact on limits given current constraints. Correctly treating the extended size of the nucleus and doing an exact integration of the Schr\"odinger equation does have a major impact relative to past analyses based on the Born approximation and naive form factors, so those improvements are essential for interpreting observational constraints. We report the corrected exclusion regions superseding previous limits from XQC, CRESST Surface Run, CMB power spectrum and extensions with Lyman-$\ensuremath{\alpha}$ and Milky Way satellites, and Milky Way gas clouds. Some limits become weaker, by an order of magnitude or more, than previous bounds in the literature which were based on perturbation theory and pointlike sources, while others become stronger. Gaps which open by correct treatment of some particular constraint can sometimes be closed using a different constraint. We also discuss the dependence on mediator mass and give approximate expressions for the velocity dependence near a resonance. Sexaquark ($uuddss$) DM with mass around 2 GeV, which exchanges QCD mesons with baryons, remains unconstrained for most of the parameter space of interest. A statement in the literature that a DM-nucleus cross section larger than ${10}^{\ensuremath{-}25}\text{ }\text{ }{\mathrm{cm}}^{2}$ implies dark matter is composite, is corrected.

On the Reionization-era Globular Cluster in the Low-mass Galaxy Eridanus II

Using color–magnitude diagrams from deep archival Hubble Space Telescope imaging, we self-consistently measure the star formation history of Eridanus II (Eri II), the lowest-mass galaxy (M ⋆(z = 0) ∼ 105 M ⊙) known to host a globular cluster (GC), and the age, mass, and metallicity of its GC. The GC (∼13.2 ± 0.4 Gyr, 〈[Fe/H]〉 = −2.75 ± 0.2 dex) and field (mean age ∼13.5 ± 0.3 Gyr, 〈[Fe/H]〉 = −2.6 ± 0.15 dex) have similar ages and metallicities. Both are reionization-era relics that formed before the peak of cosmic star and GC formation (z ∼ 2–4). The ancient star formation properties of Eri II are not extreme and appear similar to z = 0 dwarf galaxies. We find that the GC was ≲4 times more massive at birth than today and was ∼10% of the galaxy's stellar mass at birth. At formation, we estimate that the progenitor of Eri II and its GC had M UV ∼ −7 to −12, making it one of the most common type of galaxy in the early universe, though it is fainter than direct detection limits, absent gravitational lensing. Archaeological studies of GCs in nearby low-mass galaxies may be the only way to constrain GC formation in such low-mass systems. We discuss the strengths and limitations in comparing archaeological and high-redshift studies of cluster formation, including challenges stemming from the Hubble Tension, which introduces uncertainties into the mapping between age and redshift.

The Z7 model of three-component scalar dark matter

We investigate, for the first time, a scenario where the dark matter consists of three complex scalar fields that are stabilized by a single Z7 symmetry. As an extension of the well-known scalar Higgs-portal, this Z7 model is also subject to important restrictions arising from the relic density constraint and from direct detection experiments. Our goal in this paper is to find and characterize the viable regions of this model, and to analyze its detection prospects in future experiments. First, the processes that affect the relic densities are identified (they include semiannihilations and conversions) and then incorporated into the Boltzmann equations for the dark matter abundances, which are numerically solved with micrOMEGAs. By means of random scans of the parameter space, the regions consistent with current data, including the recent direct detection limit from the LZ experiment, are selected. Our results reveal that the Z7 model is indeed viable over a wide range of dark matter masses and that both conversions and semiannihilations play an important role in determining the relic densities. Remarkably, we find that in many cases all three of the dark matter particles give rise to observable signals in future direct detection experiments, providing a suitable way to test this scenario.

WIMP and FIMP dark matter in the inert doublet plus singlet model

We consider multicomponent dark matter in a model where one dark matter component is feebly interacting (FIMP) while the second is weakly interacting (WIMP). The model contains an inert scalar doublet and a complex scalar singlet and features a discrete ${Z}_{4}$ symmetry. Using new features of micromegas that allow us to compute the relic density for multicomponent dark matter including WIMPs and FIMPs, we determine the parameter space that satisfies theoretical constraints, collider constraints, relic density as well as direct and indirect detection limits. We discuss the possibility to probe the model through collider and astrophysical searches. We find that it is possible that the FIMP forms the dominant dark matter (DM) component, in this case the astrophysical signatures of the WIMP are much suppressed. We also explore the case where the doublet can decay into pairs of singlets leaving only one DM component, the FIMP. These scenarios are constrained by cosmology, notably big bang nucleosynthesis, and can be explored at colliders while astrophysical signatures are suppressed.

Search for Light Fermionic Dark Matter Absorption on Electrons in PandaX-4T.

We report a search on sub-MeV fermionic dark matter absorbed by electrons with an outgoing active neutrino using the 0.63 tonne year exposure collected by the PandaX-4T liquid xenon experiment. No significant signals are observed over the expected background. The data are interpreted into limits to the effective couplings between such dark matter and the electron. For axial-vector or vector interactions, our sensitivity is competitive in comparison to existing astrophysical bounds on the decay of such a dark matter candidate into photon final states. In particular, we present the first direct detection limits for a vector (axial-vector) interaction which are the strongest in the mass range from 35 to 55 (25 to 45) keV/c^{2} in comparison to other astrophysical and cosmological constraints.

Light dark matter around 100 GeV from the inert doublet model

We made global fits of the inert Higgs doublet model (IDM) in the light of collider and dark matter search limits and the requirement for a strongly first-order electroweak phase transition (EWPT). These show that there are still IDM parameter spaces compatible with the observational constraints considered. In particular, the data and theoretical requirements imposed favour the hypothesis for the existence of a scalar dark matter candidate around 100 GeV. This is mostly due to the pull towards lower masses by the EWPT constraint. The impact of electroweak precision measurements, the dark matter direct detection limits, and the condition for obtaining a strongly enough first-order EWPT, all have strong dependence, sometimes in opposing directions, on the mass splittings between the IDM scalars.

Pseudo-Goldstone dark matter model with CP violation

We consider an explicitly CP-violating model with two Higgs doublets and one complex singlet scalar. The singlet S is charged under a global U(1) symmetry which is softly broken by a mass term μ2S2 + H.c.. Imaginary part of S is a stable dark matter candidate which at the tree level, in the limit of zero momentum transfer, decouples from nucleons naturally satisfying all existing direct detection limits on dark matter scattering cross-section. It is explicitly shown that within this framework in the alignment limit CP violation is still present in contrast to a popular version of a 2-Higgs doublet model with softly broken Z2 symmetry. In this context, we investigate dark matter implications of the model both with and without CP violation in the scalar sector. In particular, dark matter relic abundance is calculated and the possibility for its indirect detection is discussed.

Probing sub-GeV leptophilic dark matter at Belle II and NA64

An analysis is given of the Belle II sensitivities and NA64 constraints on the sub-GeV Dirac dark matter that interacts with charged leptons. We consider two different types of interactions between sub-GeV Dirac dark matter and the charged leptons: the EFT operators and the light vector mediators. We compute the Belle II mono-photon sensitivities on sub-GeV dark matter with 50 ab−1 data which are expected to be accumulated in the full Belle II runs. Although the Belle II mono-photon sensitivities on the EFT operators are of similar size as the LEP constraints, Belle II can probe new parameter space of the light vector mediator models that are unexplored by LEP. For both the EFT operators and the light vector mediator models, the Belle II mono-photon sensitivities can be several orders of magnitude stronger than the current dark matter direct detection limits, as well as the white dwarf limits. The light vector mediator can also be directly searched for by reconstructing the invariant mass of its di-lepton decay final states at Belle II, which is found to be complementary to the mono-photon channel. We compute the NA64 constraints on the sub-GeV Dirac dark matter and provide analytic expressions of the dark matter cross section in the Weizsäcker-Williams approximation, for the EFT operators, and for the light vector mediator models. We find that the current NA64 data (with 2.84 × 1011 electron-on-target events) provide strong constraints on sub-GeV dark matter. Although the NA64 constraints are found to be about one order of magnitude smaller than the Belle II sensitivities for the EFT operators, NA64 can probe some regions of the parameter space in the light vector mediator models that are beyond the reach of Belle II. We also find that Belle II and NA64 can probe the canonical dark matter annihilation cross section in thermal freeze-out in a significant portion of the parameter space of the models considered.

Fermion and scalar two-component dark matter from a Z4 symmetry

We revisit a two-component dark matter model in which the dark matter particles are a singlet fermion ($\psi$) and a singlet scalar ($S$), both stabilized by a single $Z_4$ symmetry. The model, which was proposed by Y. Cai and A. Spray, is remarkably simple, with its phenomenology determined by just five parameters: the two dark matter masses and three dimensionless couplings. In fact, $S$ interacts with the Standard Model particles via the usual Higgs-portal, whereas $\psi$ only interacts directly with $S$, via the Yukawa terms $\overline{\psi^c}(y_s+y_p\gamma^5)\psi\,S$. We consider the two possible mass hierarchies among the dark matter particles, $M_S<M_\psi$ and $M_\psi<M_S$, and numerically investigate the consistency of the model with current bounds. The main novelties of our analysis are the inclusion of the $y_p$ coupling, the update of the direct detection limits, and a more detailed characterization of the viable parameter space. For dark matter masses below $1.3$ TeV or so, we find that the model not only is compatible with all known constraints, but that it also gives rise to observable signals in future dark matter experiments. Our results show that both dark matter particles may be observed in direct detection experiments and that the most relevant indirect detection channel is due to the annihilation of $\psi$. We also argue that this setup can be extended to other $Z_N$ symmetries and additional dark matter particles.

Interdependence of the new “MUON G-2” result and the W-boson mass

The electroweak (EW) sector of the Minimal Supersymmetric extension of the Standard Model (MSSM), assuming the lightest neutralino as Dark Matter (DM) candidate, can account for a variety of experimental results. This includes the DM direct detection limits, the searches for EW superpartners at the LHC, and in particular the discrepancy between the experimental result for the anomalous magnetic moment of the muon, (g-2)_mu , and its Standard Model (SM) prediction. The new “MUON G-2” result, combined with the older BNL result on (g-2)_mu , yields a deviation from the SM prediction of Delta a_mu = ({25.1}pm {5.9}) times 10^{-10}, corresponding to {4.2},sigma . Using this updated bound, together with the other constraints, we calculate the MSSM prediction for the mass of the W boson, M_W. We assume contributions only from the EW sector, i.e. the colored sector of the MSSM, in agreement with the search limits, is taken to be heavy. We investigate five scenarios, distinguished by the mechanisms which yield a relic DM density in agreement with the latest Planck bounds. We find that with the new (g-2)_mu result taken into account and depending on the scenario, values up to are reached. The largest values are obtained for wino DM and in the case of slepton co-annihilation, where points well within the 1,sigma range of the experimental world average of M_W^{mathrm {exp}}= 80.379 pm 0.012 ,, mathrm {GeV} are reached, whereas the SM predicts a too small value of M_W^{mathrm {SM}}= 80.353 ,, mathrm {GeV}. We analyze the dependence of M_W^{mathrm {MSSM}} on the relevant masses of the EW superpartners and demonstrate that future M_W measurements, e.g. at the ILC, could distinguish between various MSSM realizations. Sizable contributions to M_W^{mathrm {MSSM}} are associated with a relatively light tilde{chi }_{1}^0, accompanied by either a light chargino or a light smuon, setting interesting targets for future collider searches.

Heavy long-lived coannihilation partner from inelastic Dark Matter model and its signatures at the LHC

The coannihilation mechanism is a well-motivated alternative to the simple thermal freeze-out mechanism, where the dark matter relic density can be obtained through the coannihilation with a partner particle of similar mass with dark matter. When the partner particle is neutral, the inelastic nature of dark matter can help it to escape the direct detection limits. In this work, we focus on the coannihilation scenario in which the annihilation cross section is dominated by the partner-partner pair annihilation. We pay special interest on the parameter space where the coannihilation partner is long-lived, which leads to displaced signatures at the collider. In such case, it opens the heavy mass parameter space for the coannihilation dark matter, comparing with those dominated by the partner-dark matter annihilation. Specifically, we study an inelastic scalar dark matter model with a specific parameter space, which realizes the domination of partner-partner pair annihilation. Then, we study two different realizations of the coannihilation partner decay and the existing constraints from the relic abundance, direct and indirect dark matter detection and the collider searches. We focus on the channel that the long-lived coannihilation partner decays to dark matter plus leptons. The high-luminosity LHC can reach good sensitivities for such heavy dark matter and coannihilation partner around 100–700 GeV.

Two dark matter candidates: The case of inert doublet and singlet scalars

We consider a multi-component dark matter model where the dark sector contains a scalar doublet and a complex scalar singlet. We impose a discrete $Z_4$ symmetry to ensure such that the lightest component of the doublet, $\tilde{A}$, and the singlet, $\tilde{S}$, are both stable. Interactions between the dark sectors impact significantly dark matter observables, they allow in particular to significantly relax the direct detection constraints on the model. To determine the parameter space that satisfies relic density, theoretical and collider constraints as well as direct and indirect detection limits, we perform two separate scans, the first includes the full parameter space of the model while the second is dedicated to scenarios with a compressed inert doublet spectrum. In the first case we find that the singlet is generally the dominant dark matter component while in the compressed case the doublet is more likely to be the dominant dark matter component. In both cases we find that the two dark matter particles can have masses that ranges from around $m_h/2$ to over the TeV scale. We emphasize the interplay between cosmological astrophysical and collider constraints and show that a large fraction of the parameter space that escapes current constraints is within the sensitivity reach of future detectors such as XENON-nT, Darwin or CTA. Important collider signatures are mostly found in the compressed spectrum case with the possibility of probing the model with searches for heavy stable charged particles and disappearing tracks. We also show that semi-annihilation processes such as $\tilde{S}\tilde{S}\to \tilde{A}Z$ could give the dominant signature in indirect detection searches.

Erratum: Direct detection limits on heavy dark matter [Phys. Rev. D 102 , 123026 (2020)

Received 6 December 2021DOI:https://doi.org/10.1103/PhysRevD.104.129903Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDark matterParticle dark matterPhysical SystemsWeakly interacting massive particlesTechniquesDark matter detectorsParticles & Fields