The Center for Axion and Precision Physics research at the Institute for Basic Science is searching for axion dark matter using ultra-low temperature microwave resonators. We report the exclusion of the axion mass range 10.7126$-$10.7186 $mu$eV with near Kim-Shifman-Vainshtein-Zakharov (KSVZ) coupling sensitivity and the range 10.16$-$11.37 $mu$eV with about 9 times larger coupling at 90$%$ confidence level. This is the first axion search result in these ranges. It is also the first with a resonator physical temperature of less than 40 mK.
Axions, originally proposed to solve the strong CP problem of quantum chromodynamics, emerge now as leading candidates of WISP dark matter. The rich phenomenology associated to the light and stable QCD axion can be described as an effective magnetic
field that can be experimentally investigated. For the QUAX experiment, dark matter axions are searched by means of their resonant interactions with electronic spins in a magnetized sample. In principle, axion-induced magnetization changes can be detected by embedding a sample in an rf cavity in a static magnetic field. In this work we describe the operation of a prototype ferromagnetic haloscope, with a sensitivity limited by thermal fluctuations and receiver noise. With a preliminary dark matter search, we are able to set an upper limit on the coupling constant of DFSZ axions to electrons $g_{aee}<4.9times10^{-10}$ at 95% C.L. for a mass of $58,mu$eV (i.,e. 14,GHz). This is the first experimental result with an apparatus exploiting the coupling between cosmological axions and electrons.
We present results of the Relic Axion Dark-Matter Exploratory Setup (RADES), a detector which is part of the CERN Axion Solar Telescope (CAST), searching for axion dark matter in the 34.67$mu$eV mass range. A radio frequency cavity consisting of 5 su
b-cavities coupled by inductive irises took physics data inside the CAST dipole magnet for the first time using this filter-like haloscope geometry. An exclusion limit with a 95% credibility level on the axion-photon coupling constant of g$_{agamma}gtrsim 4times10^{-13} text{GeV}^{-1}$ over a mass range of 34.6738 $mu$eV < $m_a$ < 34.6771 $mu$eV is set. This constitutes a significant improvement over the current strongest limit set by CAST at this mass and is at the same time one of the most sensitive direct searches for an axion dark matter candidate above the mass of 25 $mu$eV. The results also demonstrate the feasibility of exploring a wider mass range around the value probed by CAST-RADES in this work using similar coherent resonant cavities.
The axion is a promising dark matter candidate, which was originally proposed to solve the strong-CP problem in particle physics. To date, the available parameter space for axion and axion-like particle dark matter is relatively unexplored, particula
rly at masses $m_alesssim1,mu$eV. ABRACADABRA is a new experimental program to search for axion dark matter over a broad range of masses, $10^{-12}lesssim m_alesssim10^{-6}$ eV. ABRACADABRA-10 cm is a small-scale prototype for a future detector that could be sensitive to the QCD axion. In this Letter, we present the first results from a 1 month search for axions with ABRACADABRA-10 cm. We find no evidence for axion-like cosmic dark matter and set 95% C.L. upper limits on the axion-photon coupling between $g_{agammagamma}<1.4times10^{-10}$ GeV$^{-1}$ and $g_{agammagamma}<3.3times10^{-9}$ GeV$^{-1}$ over the mass range $3.1times10^{-10}$ eV - $8.3times10^{-9}$ eV. These results are competitive with the most stringent astrophysical constraints in this mass range.
We report on the first results from a new microwave cavity search for dark matter axions with masses above $20~mutext{eV}$. We exclude axion models with two-photon coupling $g_{agammagamma} gtrsim 2times10^{-14}~text{GeV}^{-1}$ over the range $23.55~
mutext{eV} < m_a < 24.0~mutext{eV}$. These results represent two important achievements. First, we have reached cosmologically relevant sensitivity an order of magnitude higher in mass than any existing limits. Second, by incorporating a dilution refrigerator and Josephson parametric amplifier, we have demonstrated total noise approaching the standard quantum limit for the first time in an axion search.
A ferromagnetic axion haloscope searches for Dark Matter in the form of axions by exploiting their interaction with electronic spins. It is composed of an axion-to-electromagnetic field transducer coupled to a sensitive rf detector. The former is a p
hoton-magnon hybrid system, and the latter is based on a quantum-limited Josephson parametric amplifier. The hybrid system consists of ten 2.1 mm diameter YIG spheres coupled to a single microwave cavity mode by means of a static magnetic field. Our setup is the most sensitive rf spin-magnetometer ever realized. The minimum detectable field is $5.5times10^{-19},$T with 9 h integration time, corresponding to a limit on the axion-electron coupling constant $g_{aee}le1.7times10^{-11}$ at 95% CL. The scientific run of our haloscope resulted in the best limit on DM-axions to electron coupling constant in a frequency span of about 120 MHz, corresponding to the axion mass range $42.4$-$43.1,mu$eV. This is also the first apparatus to perform an axion mass scanning by changing the static magnetic field.