Session Q10: Dark Matter Constraints from Earth

Live

The constituents of dark matter are still unknown, and the viable possibilities span a very large mass range. Specific scenarios for the origin of dark matter sharpen the focus on a narrower range of masses: the natural scenario where dark matter originates from thermal contact with familiar matter in the early Universe requires the DM mass to lie within about an MeV to 100 TeV. Considerable experimental attention has been given to exploring Weakly Interacting Massive Particles in the upper end of this range (few GeV – ~TeV), while the region ~MeV to ~GeV is largely unexplored. Most of the stable constituents of known matter have masses in this lower range, tantalizing hints for physics beyond the Standard Model have been found here, and a thermal origin for dark matter works in a simple and predictive manner in this mass range as well. It is therefore a priority to explore. If there is an interaction between light DM and ordinary matter, as there must be in the case of a thermal origin, then there necessarily is a production mechanism in accelerator-based experiments. The most sensitive way, (if the interaction is not electron-phobic) to search for this production is to use a primary electron beam to produce DM in fixed-target collisions. The Light Dark Matter eXperiment (LDMX)   

Live

We present the current status, and future plans of The Oscillating Resonant Group AxioN (ORGAN) Experiment, a high-mass ($\sim60-200~\mu$eV) microwave cavity axion haloscope. ORGAN comprises various phases and sub-phases, having commenced in 2021, and running until 2026. We will discuss each phase, their experimental details, and projected reach. Initial phases rely on well-developed technologies such as traditional tuning-rod resonators, and HEMT amplifiers. Future phases project the use of novel resonant designs based on dielectric structures, and advanced readout techniques based on GHz single photon counters (SPCs). We will discuss the proposed resonant designs, and report on progress in the development of SPCs. It is projected that, with the development of efficient SPCs, within the 12+ Tesla, milli-Kelvin environment available, DFSZ sensitivity is attainable over the entire mass range within the time-scale of the experiment.   

Live

In the Sexaquark Dark Matter scenario, DM is composed of six quarks (uuddss) and interacts with baryons by meson exchange. The SDM-baryon interaction is non-perturbative in much of the natural parameter space and the cross section exhibits resonant behavior which cannot be described by Born approximation. We re-evaluate the possible SDM parameter space, imposing constraints from XQC, CMB and dewar experiments. Because there is no one-to-one mapping between the parameters and the cross section and the scaling of cross section with the atomic mass is model dependent, it is non-trivial to compare different experiments universally in the DM-nucleon cross section vs. DM mass plane. We demonstrate how this comparison is possible in this talk. If the interaction between SDM and baryon is attractive, SDM can be captured by nucleus and form exotic isotopes, generating photon radiation signal if captured in an excited state. The capture cross section is also highly resonant. We evaluated the abundance of the isotopes in the Earth and possible capture signal in experiments like the XQC.   

Live

In recent decades, xenon Time Projection Chambers (TPCs) have set world-leading limits on the parameter space for Weakly-Interacting Massive Particle (WIMP) dark matter interacting via elastic scattering channels. However, the absence of any WIMP signal in the low-energy nuclear recoil regime (<100 keV) as predicted by canonical theories merits exploring new parameter space. One natural extension is to search for higher energy WIMP interaction signatures, such as those predicted by effective field theory models or inelastic scattering channels. For a successful search in this energy regime, nuclear recoils of hundreds of keV must be well-characterized. Unfortunately, current calibrations for xenon TPCs only reliably extend to around 100 keV nuclear recoils, and large uncertainties beyond this range hinder accurate characterization of higher energy recoils. This talk will present our effort to calibrate xenon's nuclear recoil response up to approximately 425 keV using the XeNeu dual-phase xenon TPC and 14.1 MeV neutrons from a Deuterium-Tritium generator. The current status of the construction and measurement, as well as the experimental setup's expected sensitivity based on simulations, will also be presented.   

Live

The Super Cryogenic Dark Matter Search (SuperCDMS) uses millikelvin cryogenic germanium and silicon detectors to obtain exceptional sensitivity to low-energy dark matter-nucleus interactions. When a particle interacts with the detector, phonons and electron-hole pairs are produced and detected. The proportion of energy deposited as phonons versus as electron-hole pairs changes with the energy of the event and with the type of scattering, either nuclear recoil or electron recoil. The detector sensitivity to ionization can also be modulated throught the Neganov-Trofimov-Luke effect by using a voltage bias across the detector. Ionization Measurement with Phonons At Cryogenic Temperatures (IMPACT) uses a small silicon SuperCDMS HV-style detector to measure the ionization yield of nuclear recoils. To do so, we used a beam of 55.7keV neutrons at TUNL and measured the scattering of this beam though the detector into 29 liquid scintillator cells placed at various angles to the beam. By comparing the scattering angle to the signal measured in the detector at various detector biases, the ionization yield can be determined. This calibration allows us to measure ionization yield for nuclear recoil energy $<$ 1keV, for which no present results exist.   

Live

A network of quantum sensors, such as the network of Rb atomic clocks aboard the Global Positioning System (GPS), have shown to be capable for searching for exotic physics, such as clumpy dark matter (DM). An example of clumpy dark matter of particular interest to our current search is Topological Defect (TD) dark matter, which may take the form of 0D monopoles or Q-balls, 1D strings, or 2D domain walls. For a 2D domain wall, we expect a well defined DM signature in the atomic clock data as the DM wall propagates through the constellation. Using a Bayesian statistical method, a search through the 20 years of archival GPS data for transient dark matter signatures from 2D thin domain walls was performed. A strict $\chi^{2}$ filter, expecting only 1 false positive in 100 years, in conjunction with the signal to noise (SNR) filter was developed to eliminate false positive events arising from poor matching to the bank of DM signal templates. Parameter estimation was performed for each potential DM candidate event, investigating the velocity, and geometry of the DM encounter. Details of these preliminary results from the archival GPS data search will be presented at the conference.   

Live

The Sun — due to its high matter density, and abundant hydrogen content — is an excellent target for studying spin dependent dark matter-proton scattering. The Sun can gravitationally trap Weakly Interacting Massive Particles (WIMPs) from the galactic halo, which then thermalize in the solar core. The captured dark matter (DM) in the Sun can annihilate into Standard Model particles including an observable flux of neutrinos. The IceCube Neutrino Observatory with its optimal sensitivity to TeV—PeV neutrinos has performed several analyses constraining the spin-dependent DM-proton cross-section more than an order of magnitude stronger than direct detection experiments. However, the parameter space with DM masses below 50 GeV has remained uncharted territory for IceCube. This work for the first time utilizes special cuts and includes ``starting events'' to extend IceCube’s sensitivity to WIMP masses down to 5 GeV. We present the results of a search for low-energy ($<$300 GeV) neutrinos correlated with the direction of the Sun using 7 years of IceCube data. Our observations exclude DM-proton scattering down to a few times $10^{-42}$ cm$^2$ for the nu-nu channel at 20 GeV, which are the world’s strongest constraints at these energies for DM annihilation directly to neutrinos.   

Live

While the Standard Model does not anticipate the existence of free particles with a fractional electric charge, fractionally charged particles (FCPs) have not been experimentally excluded. The Standard Model of particle physics does have quarks and antiquarks with $\pm\,2e$/3 and $\pm\,e$/3 charges, but their strong interaction binds them inside unit-charged hadrons. Free fractionally charged particles are a feature of viable extensions to the Standard Model with extra U(1) gauge symmetries. I report the results of an analysis of CDMSlite Run 2 Period 1 data resulting in the first direct detection limits on cosmogenic FCPs with an electric charge as small as $e/10^8$ and the most stringent limit on vertical intensity for FCPs with an electric charge $\leq$$e/160$. This analysis is also the first to consider cosmogenic FCPs with a wide range of masses (5 MeV/c$^2$ - 100 TeV/c$^2$) and velocities ($\beta\gamma$ = 0.1 - 10$^6$).   

On Demand

Macroscopic dark matter (or macro) provides a broad class of alternative candidates to particle dark matter. These candidates would transfer energy primarily through elastic scattering, and this linear energy deposition would produce observable signals if a macro were to traverse the atmosphere. We study the fluorescence emission produced by a macro passing through the atmosphere. We estimate the sensitivity of EUSO-SPB2 to constrain the two-dimensional parameter space ($\sigma$ vs. $M$), where $M$ is the macro mass and $\sigma$ its cross sectional area.