Direct Detection Limits Research Articles

The new \u201cMUON G-2\u201d result and supersymmetry

The electroweak (EW) sector of the Minimal Supersymmetric Standard Model (MSSM), with the lightest neutralino as Dark Matter (DM) candidate, can account for a variety of experimental data. This includes the DM content of the universe, DM direct detection limits, EW SUSY searches at the LHC and in particular the so far persistent 3-4,sigma discrepancy between the experimental result for the anomalous magnetic moment of the muon, (g-2)_mu , and its Standard Model (SM) prediction. The recently published “MUON G-2” result is within {0.8},sigma in agreement with the older BNL result on (g-2)_mu . The combination of the two results was given as a_mu ^{mathrm{exp}} = (11 659 {206.1}pm {4.1}) times 10^{-10}, yielding a new deviation from the SM prediction of Delta a_mu = ({25.1}pm {5.9}) times 10^{-10}, corresponding to {4.2},sigma . Using this improved bound we update the results presented in Chakraborti et al. (Eur Phys J C 80(10):984, 2020) and set new upper limits on the allowed parameters space of the EW sector of the MSSM. We find that with the new (g-2)_mu result the upper limits on the (next-to-) lightest SUSY particle are in the same ballpark as previously, yielding updated upper limits on these masses of sim 750 ,, mathrm {GeV}. In this way, a clear target is confirmed for future (HL-)LHC EW searches, as well as for future high-energy e^+e^- colliders, such as the ILC or CLIC.

Dark matter from a complex scalar singlet: the role of dark CP and other discrete symmetries

We study the case of a pseudo-scalar dark matter candidate which emerges from a complex scalar singlet, charged under a global U(1) symmetry, which is broken both explicitly and spontaneously. The pseudo-scalar is naturally stabilized by the presence of a remnant discrete symmetry: dark CP. We study and compare the phenomenology of several simplified models with only one explicit symmetry breaking term. We find that several regions of the parameter space are able to reproduce the observed dark matter abundance while respecting direct detection and invisible Higgs decay limits: in the resonances of the two scalars, featuring the known as forbidden or secluded dark matter, and through non-resonant Higgs-mediated annihilations. In some cases, combining different measurements would allow one to distinguish the breaking pattern of the symmetry. Moreover, this setup admits a light DM candidate at the sub-GeV scale. We also discuss the situation where more than one symmetry breaking term is present. In that case, the dark CP symmetry may be spontaneously broken, thus spoiling the stability of the dark matter candidate. Requiring that this does not happen imposes a constraint on the allowed parameter space. Finally, we consider an effective field theory approach valid in the pseudo-Nambu-Goldstone boson limit and when the U(1) breaking scale is much larger than the electroweak scale.

Ultra-magnetic field sensitive magnetoelectric composite with sub-pT detection limit at low frequency enabled by flash photon annealing

An ultra-sensitive magnetic field detector is demonstrated in a bilayer magnetoelectric (ME) composite structure employing a flash photon annealing (FPA) treated amorphous Metglas (FeBSi) alloy and piezoelectric single crystal macro fiber composites (SFC). A millisecond FPA annealing approach altered the magnetostrictive and mechanical properties of Metglas by annealing at a high temperature without inducing severe embrittlement. The ME composite (MEC) fabricated with FPA-treated Metglas (FPA-MEC) exhibited an enhanced ME coupling coefficient (at a resonance condition ~47% and at an off-resonance condition ~52%) relative to that of untreated Metglas based ME composite (pristine MEC), owing to the improved magnetic flux concentration/piezo-magnetic coefficient and reduced resonance loss in Metglas. This led to the realization of an ultra-sensitive magnetic field sensor with a direct detection limit of 0.5 pT [1 order improved performance compared to the pristine MEC (sensing limit of 5 pT)] at an extremely low resonance frequency condition (<100 Hz). The obtained results demonstrate a feasible way to design magnetic sensors for detecting bio-magnetic and extremely low-frequency (ELF) magnetic fields under ambient conditions.

Constraints on Lightly Ionizing Particles from CDMSlite.

The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to lightly ionizing particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically produced LIPs with an electric charge smaller than e/(3×10^{5}), as well as the strongest limits for charge ≤e/160, with a minimum vertical intensity of 1.36×10^{-7} cm^{-2} s^{-1} sr^{-1} at charge e/160. These results apply over a wide range of LIP masses (5 MeV/c^{2} to 100 TeV/c^{2}) and cover a wide range of βγ values (0.1-10^{6}), thus excluding nonrelativistic LIPs with βγ as small as 0.1 for the first time.

Direct Imaging of Exoplanets beyond the Radial Velocity Limit: Application to the HD 134987 System

Abstract Future direct imaging missions will primarily observe planets that have been previously detected, mostly via the radial velocity (RV) technique, to characterize planetary atmospheres. In the meantime, direct imaging may discover new planets within existing planetary systems that have bright enough reflected flux but insufficient signals for other methods to detect. Here we investigate the parameter space within which planets are unlikely to be detected by RV in the near future due to precision limitations but could be discovered through reflected light with future direct imaging missions. We use the HD 134987 system as a working example, combine RV and direct imaging detection limit curves in the same parameter space through various assumptions, and insert a fictitious planet into the system while ensuring that it lies between the RV and imaging detection limits. Planet validity tested through dynamical simulations and retrieval tests revealed that the planet could indeed be detected by imaging while remaining hidden from RV surveys. Direct imaging retrieval was carried out using starshade simulations for two mission concepts: the Starshade Rendezvous Probe, which could be coupled with the Nancy Grace Roman Space Telescope, and the Habitable Exoplanet Observatory. This method is applicable to all other systems and high-contrast direct imaging instruments and could help inform future imaging observations and data analysis on the discovery of new exoplanets.

New constraints on radiative seesaw models from IceCube and other neutrino detectors

Dark matter (DM) scattering and its subsequent capture in the Sun can boost the local relic density, leading to an enhanced neutrino flux from DM annihilations that is in principle detectable at neutrino telescopes. We calculate the event rates expected for a radiative seesaw model containing both scalar triplet and singlet-doublet fermion DM candidates. In the case of scalar DM, the absence of a spin dependent scattering on nuclei results in a low capture rate in the Sun, which is reflected in an event rate of less than one per year in the current IceCube configuration with 86 strings. For singlet-doublet fermion DM, there is a spin dependent scattering process next to the spin independent one, which significantly boosts the event rate and thus makes indirect detection competitive with respect to the direct detection limits imposed by PICO-60. Due to a correlation between both scattering processes, the limits on the spin independent cross section set by XENON1T exclude also parts of the parameter space that can be probed at IceCube. Previously obtained limits by ANTARES, IceCube and Super-Kamiokande from the Sun and the Galactic Center are shown to be much weaker.

Exploring direct detection suppressed regions in a simple 2-scalar mediator model of scalar dark matter

We explore regions of parameter space that give rise to suppressed direct detection cross sections in a simple model of scalar dark matter with a scalar portal that mixes with the standard model Higgs. We found that even this simple model allows considerable room in the parameter space that has not been excluded by direct detection limits. A number of effects leading to this result have been previously noted. Our main new result explores interference effects between different contributions to DM annihilation when the DM mass is larger than the scalar portal mass. New annihilation channels open up and the parameters of the model need to compensate to give the correct DM relic abundance, resulting in smaller direct detection cross sections. We find that even in a very simple model of DM there are still sizeable regions of parameter space that are not ruled out by experiment.

T \u2212 b \u2212 \u03c4 Yukawa unification in non-holomorphic MSSM

We show that in the CMSSM with the non-holomorphic soft SUSY breaking terms, the Yukawa coupling unification of the third family fermions at the GUT scale, called t − b − τ Yukawa unification (YU), is possible under the recent collider and Dark Matter results. The YU parameter can also be found Rtbτ≈ 1, called perfect unification. We find that the squark masses exceed 3 TeV while the stau can be considerably lighter. In the case of YU, the tan β is in the interval [46,55]. We obtain bino-like dark matter (DM) of mass in the range of 0.6 TeV ≲ {m}_{upchi_1^0} ≲ 1.3 TeV where the recent Dark Matter direct detection limits are also satisfied. We also identify A-resonance solutions which reduce the relic abundance of LSP neutralino down to the ranges compatible with the current Planck measurements.

Recasting direct detection limits within micrOMEGAs and implication for non-standard dark matter scenarios

Direct detection experiments obtain 90% upper limits on the elastic scattering cross sections of dark matter with nucleons assuming point-like interactions and standard astrophysical and cosmological parameters. In this paper we provide a recasting of the limits from XENON1T, PICO-60, CRESST-III and DarkSide-50 and include them in micrOMEGAs. The code can then be used to directly impose constraints from these experiments on generic dark matter models under different assumptions about the DM velocity distribution or on the nucleus form factors. Moreover, new limits on the elastic scattering cross sections can be obtained in the presence of a light t-channel mediator or of millicharged particles.

Time-Resolved Focused Ion Beam Microscopy: Modeling, Estimation Methods, and Analyses

In a focused ion beam (FIB) microscope, source particles interact with a small volume of a sample to generate secondary electrons that are detected, pixel by pixel, to produce a micrograph. Randomness of the number of incident particles causes excess variation in the micrograph, beyond the variation in the underlying particle-sample interaction. We recently demonstrated that joint processing of multiple time-resolved measurements from a single pixel can mitigate this effect of source shot noise in helium ion microscopy. This paper is focused on establishing a rigorous framework for understanding the potential for this approach. It introduces idealized continuous- and discrete-time abstractions of FIB microscopy with direct electron detection and estimation-theoretic limits of imaging performance under these measurement models. Novel estimators for use with continuous-time measurements are introduced and analyzed, and estimators for use with discrete-time measurements are analyzed and shown to approach their continuous-time counterparts as time resolution is increased. Simulated FIB microscopy results are consistent with theoretical analyses and demonstrate that substantial improvements over conventional FIB microscopy image formation are made possible by time-resolved measurement.

Direct detection limits on heavy dark matter

Multiply-interacting massive particles (MIMPs) are heavy (>10^10 GeV/c^2) dark matter particles that interact strongly with regular matter, but may have evaded detection due to the low number density required to make up the local dark matter halo. These particles could leave track-like signatures in current experiments, similar to lightly-ionizing particles. We show that previously calculated limits from the MAJORANA Demonstrator on the flux of lightly-ionizing particles can be used to exclude MIMP dark matter parameter space up to a mass of 10^15 GeV/c^2. We also calculate limits from the standard XENON1T analysis in this high-mass regime, properly taking into account flux limitations and multi-scatter effects. Finally, we show that a dedicated MIMP analysis using the XENON1T dark matter search could probe unexplored parameter space up to masses of 10^18 GeV/c^2.

CRISPR-Cas12a coupled with terminal deoxynucleotidyl transferase mediated isothermal amplification for sensitive detection of polynucleotide kinase activity

Abstract Polynucleotide kinase (PNK) is an important DNA damage repair-related enzyme and also a promising therapeutic target in various diseases. Here, we developed a dual amplified sensing strategy based on the combination of terminal deoxynucleotidyl transferase (TdT) and CRISPR-Cas12a for high selective and sensitive detection of PNK activity in cell lysates and also inhibitor screening. In this sensing system, the PNK converted the 3′-phosphate DNA to 3′-hydroxy DNA, and then the TdT catalyzed to add a long poly-adenine (poly (A)) at the 3′−OH terminus DNA (as first amplified step). The produced poly (A) tail acted as activator to trigger the Cas12a trans-cleavage (non-target) activity to cleave reporter probes for fluorescence detection (as second amplified step). The dual amplified steps lead to a synergetic signal amplification effect for sensitive detection of PNK activity. The developed sensing platform enable detect PNK activity with linear range from 0 to 1 U/mL and a direct detection limit of 5 × 10−4 U/mL. It was also successfully used for PNK inhibitor screening and PNK activity detection in cell extracts even at a single-cell level. The efficient dual amplified method can broaden the CRISPR/Cas-based sensing systems in other bio-/chem-analysis fields.

Informing dark matter direct detection limits with the ARTEMIS simulations

Dark matter (DM) direct detection experiments aim to place constraints on the DM-nucleon scattering cross-section and the DM particle mass. These constraints depend sensitively on the assumed local DM density and velocity distribution function. While astrophysical observations can inform the former (in a model-dependent way), the latter is not directly accessible with observations. Here we use the high-resolution ARTEMIS cosmological hydrodynamical simulation suite of 42 Milky Way-mass halos to explore the spatial and kinematical distributions of the DM in the solar neighbourhood, and we examine how these quantities are influenced by substructures, baryons, the presence of dark discs, as well as general halo-to-halo scatter (cosmic variance). We also explore the accuracy of the standard Maxwellian approach for modelling the velocity distribution function. We find significant halo-to-halo scatter in the density and velocity functions which, if propagated through the standard halo model for predicting the DM detection limits, implies a significant scatter about the typically quoted limit. We also show that, in general, the Maxwellian approximation works relatively well for simulations that include the important gravitational effects of baryons, but is less accurate for collisionless (DM-only) simulations. Given the significant halo-to-halo scatter in quantities relevant for DM direct detection, we advocate propagating this source of uncertainty through in order to derive conservative DM detection limits.

Dirac dark matter in U(1)B−L with the Stueckelberg mechanism

We investigate a U(1)B−L gauge extension of the Standard Model (SM) where the gauge boson mass is generated by the Stueckelberg mechanism. Three right-handed neutrinos are added to cancel the gauge anomaly and hence the neutrino masses can be explained. A new Dirac fermion could be a WIMP dark matter whose interaction with the SM sector is mediated by the new gauge boson. Assuming the perturbativity of the gauge coupling up to the Planck scale, we find that only the resonance region is feasible for the dark matter abundance. After applying the ΔNeff constraints from the current Planck experiment, the collider search constraints as well as the dark matter direct detection limits, we observe that the B−L charge of dark matter satisfies |Qχ|>0.11. Such a scenario might be probed conclusively by the projected CMB-S4 experiment, assuming the right-handed neutrinos are thermalized with the SM sector in the early universe.

Complementarity of the future e+e− colliders and gravitational waves in the probe of complex singlet extension to the standard model

In this work, we study the future probes of the complex singlet extension to the Standard Model (cxSM). This model is possible to realize a strongly first-order electroweak phase transition (SFOEWPT). The cxSM naturally provides dark matter (DM) candidate, with or without an exact $\mathbb{Z}_2$ symmetry in the scalar sector. The benchmark models which can realize the SFOEWPT are selected, and passed to the current observational constraints to the DM candidates, including the relic densities and the direct detection limits set by the latest XENON1T results. We then calculate the one-loop corrections to the SM-like Higgs boson decays and the precision electroweak parameters due to the cxSM scalar sector. We perform a global fit to the benchmark models and study the extent to which they can be probed by the future high-energy $e^+ e^-$ colliders, such as CEPC and FCC-ee. Besides, the gravitational wave (GW) signals generated by the benchmark models are also evaluated. We further find that the future GW detector, such as LISA, is complementary in probing the benchmark models that are beyond the sensitivity of the future precision tests at the $e^+ e^-$ colliders.

Self-Powered Biosensing Platform Based on "Signal-On" Enzymatic Biofuel Cell for DNA Methyltransferase Activity Analysis and Inhibitor Screening.

Aberrant DNA methylation catalyzed by DNA methyltransferases (MTase) has proved to be associated with human diseases such as cancers. Thus, the development of an efficient strategy to accurately detect DNA MTase is highly desirable in medical diagnostics. Herein, we proposed a robust "signal-on" enzymatic biofuel cell (EBFC)-based self-powered biosensing platform with excellent anti-interference ability for DNA MTase activity analysis and inhibitor screening. In the presence of target MTase, the MTase-catalyzed DNA methylation occurred and hindered the HpaII endonuclease-catalyzed dsDNA dissociation, which enabled more bilirubin oxidase (BOD) to immobilize at the cathode surface via amidation. Then, BOD-catalyzed oxygen reduction took place by accepting electrons generated at the anode via glucose oxidation, thus leading to an elevated open-circuit voltage value, the amplitude of which was directly related to MTase concentration. The direct detection limit of the M.SssI assay was down to 0.005 U/mL, which was lower than that of those reported results. Notably, the as-proposed protocol was competent to detect DNA MTase activity directly in human serum samples without enrichment and separation, and applicable to the screening of M.SssI inhibitors. Considering the virtues of the excellent anti-interference ability, no requirement of external power, simplicity, and high accuracy, the biosensing platform would hold great potential in DNA MTase bioassay and clinical diagnosis of cancers.

Complex scalar dark matter in the gauged two-Higgs-doublet model

The complex scalar dark matter (DM) candidate in the gauged two Higgs doublet model (G2HDM), stabilized by a peculiar hidden parity ($h$-parity), is studied in detail. We explore the parameter space for the DM candidate by taking into account the most recent DM constraints from various experiments, in particular, the PLANCK relic density measurement and the current DM direct detection limit from XENON1T. We separate our analysis in three possible compositions for the mixing of the complex scalar. We first constrain our parameter space with the vacuum stability and perturbative unitarity conditions for the scalar potential, LHC Higgs measurements, plus Drell-Yan and electroweak precision test constraints on the gauge sector. We find that DM dominated by composition of the inert doublet scalar is completely excluded by further combining the previous constraints with both the latest results from PLANCK and XENON1T. We also demonstrate that the remaining parameter space with two other DM compositions can be further tested by indirect detection like the future CTA gamma-ray telescope.

DNA Tetrahedra-Cross-linked Hydrogel Functionalized Paper for Onsite Analysis of DNA Methyltransferase Activity Using a Personal Glucose Meter.

Despite the recent developments on the construction of point-of-care testing (POCT) devices, it is still a big challenge to build portable POCT tools for simple, sensitive, selective, and quantitative determination of disease-related biomarkers. With this in mind, we developed a simple and user-friendly POCT tool for onsite analysis of DNA adenine methyltransferase (Dam) activity by using DNA tetrahedra-based hydrogel to trap glucose-producing enzymes for target recognition and signal transduction. The enzyme-encapsulated DNA hydrogel and the substrate of enzyme were separately modified on papers and then combined onto a commercial glucose test strip for the sensitive evaluation of Dam activity via using a personal glucose meter (PGM) for quantitative signal readout. Taking advantage of the great amount of enzyme entrapped in DNA hydrogel and the high signal amplification ability of enzyme, this POCT tool is capable of highly sensitive and selective determination of Dam activity with a direct detection limit down to 0.001 U/mL, which is superior to that of most previously reported biosensors. Furthermore, this device can also be applied to screen inhibitor and analyze Dam activity in spiked serum samples, indicating the great potential for clinical practice and diagnostic applications. Additionally, all the reactions for Dam assay are performed on paper, which is simple and deliverable to end-users for medical diagnostics at home or in-field.

Reviving millicharged dark matter for 21-cm cosmology

The existence of millicharged dark matter (mDM) can leave a measurable imprint on 21-cm cosmology through mDM-baryon scattering. However, the minimal scenario is severely constrained by existing cosmological bounds on both the fraction of dark matter that can be millicharged and the mass of mDM particles. We point out that introducing a long-range force between a millicharged subcomponent of dark matter and the dominant cold dark matter (CDM) component leads to efficient cooling of baryons in the early universe, while also significantly extending the range of viable mDM masses. Such a scenario can explain the anomalous absorption signal in the sky-averaged 21-cm spectrum observed by EDGES, and leads to a number of testable predictions for the properties of the dark sector. The mDM mass can then lie between 10 MeV and a few hundreds of GeVs, and its scattering cross section with baryons lies within an unconstrained window of parameter space above direct detection limits and below current bounds from colliders. In this allowed region, mDM can make up as little as $10^{-8}$ of the total dark matter energy density. The CDM mass ranges from 10 MeV to a few GeVs, and has an interaction cross section with the Standard Model that is induced by a loop of mDM particles. This cross section is generically within reach of near-future low-threshold direct detection experiments.

Testing electroweak SUSY for muon g − 2 and dark matter at the LHC and beyond

Given that the LHC experiment has produced strong constraints on the colored supersymmetric particles (sparticles), testing the electroweak supersymmetry (EWSUSY) will be the next crucial task at the LHC. On the other hand, the light electroweakinos and sleptons in the EWSUSY can also contribute to the dark matter (DM) and low energy lepton observables. The precision measurements of them will provide the indirect evidence of SUSY. In this work, we confront the EWSUSY with the muon g − 2 anomaly, the DM relic density, the direct detection limits and the latest LHC Run-2 data. We find that the sneutrino DM or the neutralino DM with sizable higgsino component has been excluded by the direct detections. Then two viable scenarios are pinned down: one has the light compressed bino and sleptons but heavy higgsinos, and the other has the light compressed bino, winos and sleptons. In the former case, the LSP and slepton masses have to be smaller than about 350 GeV. While in the latter case, the LSP and slepton masses have to be smaller than about 700 GeV and 800 GeV, respectively. From investigating the observability of these sparticles in both scenarios at future colliders, it turns out that the HE-LHC with a luminosity of 15 ab−1 can exclude the whole BHL and most part of BWL scenarios at 2σ level. The precision measurement of the Higgs couplings at the lepton colliders could play a complementary role of probing the BWL scenario.