We report on the results from a search for dark matter axions with the HAYSTAC experiment using a microwave cavity detector at frequencies between 5.6 and 5.8 GHz. We exclude axion models with two ...photon coupling gaγγ≳2×10−14 GeV−1, a factor of 2.7 above the benchmark KSVZ model over the mass range 23.15<ma<24.0 μeV. This doubles the range reported in our previous paper. We achieve a near-quantum-limited sensitivity by operating at a temperature T<hν/2kB and incorporating a Josephson parametric amplifier (JPA), with improvements in the cooling of the cavity further reducing the experiment’s system noise temperature to only twice the standard quantum limit at its operational frequency, an order of magnitude better than any other dark matter microwave cavity experiment to date. This result concludes the first phase of the HAYSTAC program utilizing a conventional copper cavity and a single JPA.
We report on the first results from a new microwave cavity search for dark matter axions with masses above 20 μeV. We exclude axion models with two-photon coupling g_{aγγ}≳2×10^{-14} GeV^{-1} over ...the range 23.55<m_{a}<24.0 μeV. 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.
The manipulation of quantum states of light
holds the potential to enhance searches for fundamental physics. Only recently has the maturation of quantum squeezing technology coincided with the ...emergence of fundamental physics searches that are limited by quantum uncertainty
. In particular, the quantum chromodynamics axion provides a possible solution to two of the greatest outstanding problems in fundamental physics: the strong-CP (charge-parity) problem of quantum chromodynamics
and the unknown nature of dark matter
. In dark matter axion searches, quantum uncertainty manifests as a fundamental noise source, limiting the measurement of the quadrature observables used for detection. Few dark matter searches have approached this limit
, and until now none has exceeded it. Here we use vacuum squeezing to circumvent the quantum limit in a search for dark matter. By preparing a microwave-frequency electromagnetic field in a squeezed state and near-noiselessly reading out only the squeezed quadrature
, we double the search rate for axions over a mass range favoured by some recent theoretical projections
. We find no evidence of dark matter within the axion rest energy windows of 16.96-17.12 and 17.14-17.28 microelectronvolts. Breaking through the quantum limit invites an era of fundamental physics searches in which noise reduction techniques yield unbounded benefit compared with the diminishing returns of approaching the quantum limit.
Background Approximately 5% to 10% of asthmatic patients achieve incomplete symptom control on current therapies. The association of IL-13 with asthma pathology and reduced corticosteroid sensitivity ...suggests a potential benefit of anti–IL-13 therapy in refractory asthma. GSK679586, a humanized mAb, inhibits IL-13 binding to both IL-13 receptor α1 and α2. Objectives We sought to evaluate the efficacy and safety of GSK679586 in patients with severe asthma refractory to maximally indicated doses of inhaled corticosteroids. Methods Patients who remained symptomatic (Asthma Control Questionnaire score ≥1.5) after uptitration to 1000 μg/d fluticasone propionate or greater were randomized to 3 once-monthly intravenous infusions of 10 mg/kg GSK679586 (n = 99) or placebo (n = 99). Results Treatment differences in adjusted mean change from baseline over 12 weeks were nonsignificant for Asthma Control Questionnaire symptom scores (the primary end point; GSK679586 = −0.31, placebo = −0.17, P = .058) and FEV1 (GSK679586 = −0.01, placebo = 0.03, P = .276). Similar analyses in patients with increased serum IgE levels, blood eosinophil counts, or both were also negative. Incidence of asthma exacerbations was similar between treatments. Most adverse events were nonserious and unrelated to treatment. Two GSK679586-treated patients had treatment-related serious adverse events (lethargy and supraventricular extrasystoles). Conclusions Although well tolerated, GSK679586 did not demonstrate clinically meaningful improvements in asthma control, pulmonary function, or exacerbations in patients with severe asthma. Further studies are needed to determine whether therapies targeting IL-13, the functionally related IL-4 cytokine, or both can provide clinical benefit in patients with severe refractory asthma or a subpopulation of these patients beyond that achievable with high-dose corticosteroids.
In experiments searching for axionic dark matter, the use of the standard threshold-based data analysis discards valuable information. We present a Bayesian analysis framework that builds on an ...existing processing protocol B. M. Brubaker, L. Zhong, S. K. Lamoreaux, K. W. Lehnert, and K. A. van Bibber, Phys. Rev. D 96, 123008 (2017) to extract more information from the data of coherent axion detectors such as operating haloscopes. The analysis avoids logical subtleties that accompany the standard analysis framework and enables greater experimental flexibility on future data runs. Performing this analysis on the existing data from the HAYSTAC experiment, we find improved constraints on the axion-photon coupling gγ while also identifying the most promising regions of parameter space within the 23.15 – 24.0 μ eV mass range. A comparison with the standard threshold analysis suggests a 36% improvement in scan rate from our analysis, demonstrating the utility of this framework for future axion haloscope analyses.
Nuclear spin-dependent parity violation arises from weak interactions between electrons and nucleons and from nuclear anapole moments. We outline a method to measure such effects, using a ...Stark-interference technique to determine the mixing between opposite-parity rotational/hyperfine levels of ground-state molecules. The technique is applicable to nuclei over a wide range of atomic number, in diatomic species that are theoretically tractable for interpretation. This should provide data on anapole moments of many nuclei and on previously unmeasured neutral weak couplings.
Abstract
Dual phase xenon detectors are widely used in experimental
searches for galactic dark matter particles. The origin of single
electron backgrounds following prompt scintillation and ...proportional
scintillation signals in these detectors is not fully understood,
although there has been progress in recent years. In this paper, we
describe single electron backgrounds in
83m
Kr
calibration events and their correlation with drift and extraction
fields, using the Particle Identification in Xenon at Yale (PIXeY)
dual-phase xenon time projection chamber. The single electron
background induced by the Fowler-Nordheim (FN) effect is measured,
and its electric field dependence is quantified. The photoionization
of grids and impurities by prompt scintillation and proportional
scintillation also contributes to the single electron background.