arXiv subjects

D. H. Speller

Publications and source records attributed to D. H. Speller.

7 recordsLinked to original sources

arXiv2026

Search for Dark Photons between 16.96--19.52 $μ$eV with the HAYSTAC Experiment

We report dark photon results from HAYSTAC Phase II using data from previously reported axion searches. Additionally, we present an analysis of an unpublished dataset covering a region between 19.46--19.52 $μ$eV. This region overlaps with a recently reported dark photon signal at 19.5 $μ$eV with a kinetic coupling strength of $|χ_{\text{rand}}| \simeq 6.5 \times 10^{-15}$ resulting from a reanalysis of previously published data from the TASEH collaboration. Given HAYSTAC's sensitivity, if such a signal were present, it would have appeared as a large $17.1σ$ excess above the noise. However, no such signal was observed. We thus exclude couplings $|χ_{\text{rand}}|\geq 4.90\times10^{-15}$ at the 90\% confidence level over the newly reported region. In addition, using our previously reported axion data, we exclude couplings $|χ_{\text{rand}}|\geq2.90\times 10^{-15}$ between 16.96--19.46 $μ$eV at the 90\% confidence level.

hep-ex↗

arXiv2025

Dark Matter Axion Search with HAYSTAC Phase II

This Letter reports new results from the HAYSTAC experiment's search for dark matter axions in our galactic halo. It represents the widest search to date that utilizes squeezing to realize sub-quantum limited noise. The new results cover 1.71 $μ$eV of newly scanned parameter space in the mass ranges 17.28-18.44 $μ$eV and 18.71-19.46 $μ$eV. No statistically significant evidence of an axion signal was observed, excluding couplings $|g_γ|\geq$ 2.75$\times$$|g_γ^{\text{KSVZ}}|$ and $|g_γ|\geq$ 2.96$\times$$|g_γ^{\text{KSVZ}}|$ at the 90$\%$ confidence level over the respective region. By combining this data with previously published results using HAYSTAC's squeezed state receiver, a total of 2.27 $μ$eV of parameter space has now been scanned between 16.96-19.46 $μ$eV, excluding $|g_γ|\geq$ 2.86$\times$$|g_γ^{\text{KSVZ}}|$ at the 90$\%$ confidence level. These results demonstrate the squeezed state receiver's ability to probe axion models over a significant mass range while achieving a scan rate enhancement relative to a quantum-limited experiment.

hep-ex↗

arXiv2023

New Results from HAYSTAC's Phase II Operation with a Squeezed State Receiver

A search for dark matter axions with masses $>10 μeV/c^{2}$ has been performed using the HAYSTAC experiment's squeezed state receiver to achieve sub-quantum limited noise. This report includes details of the design and operation of the experiment previously used to search for axions in the mass ranges $16.96-17.12$ and $17.14-17.28 μeV/c^{2}$($4.100-4.140$GHz) and $4.145-4.178$GHz) as well as upgrades to facilitate an extended search at higher masses. These upgrades include improvements to the data acquisition routine which have reduced the effective dead time by a factor of 5, allowing for the new region to be scanned $\sim$1.6 times faster with comparable sensitivity. No statistically significant evidence of an axion signal is found in the range $18.44-18.71μeV/c^{2}$($4.459-4.523$GHz), leading to an aggregate upper limit exclusion at the $90\%$ level on the axion-photon coupling of $2.06\times g_γ^{KSVZ}$.

hep-ex↗

arXiv2022

EIT spectroscopy of high-lying Rydberg states in $^{39}K$

We present a study of the Rydberg spectrum in $^{39}K$ for $nS$ and $nD_{3/2}$ series connected to $5^2P_{1/2}$ using two-photon spectroscopy based on EIT in a heated vapor cell. We observed some 80 transitions from $5P_{1/2}$ to Rydberg states with principal quantum numbers $n\sim50-90$, and determined their transition frequencies and state energies with sub-GHz precision. Our spectroscopy results lay the groundwork for using Rydberg atoms as sensitive microwave photon detectors in searches for dark matter axions in the $\sim40-200$ $μ$eV mass range, which is a prime range for future axion searches suggested by theory studies.

physics.atom-ph↗

arXiv2020

A quantum-enhanced search for dark matter axions

In dark matter axion searches, quantum uncertainty manifests as a fundamental noise source, limiting the measurement of the quadrature observables used for detection. We use vacuum squeezing to circumvent the quantum limit in a search for a new particle. 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 favored by recent theoretical projections. We observe no signature of dark matter axions in the combined $16.96-17.12$ and $17.14-17.28\spaceμ\text{eV}/c^2$ mass window for axion-photon couplings above $g_γ = 1.38\times g_γ^\text{KSVZ}$, reporting exclusion at the 90% level.

quant-ph↗

arXiv2020

An improved analysis framework for axion dark matter searches

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 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 $g_γ$ 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.

astro-ph.IM↗

arXiv2018

Results from phase 1 of the HAYSTAC microwave cavity axion experiment

We report on the results from a search for dark matter axions with the HAYSTAC experiment using a microwave cavity detector at frequencies between 5.6-5.8$\, \rm Ghz$. We exclude axion models with two photon coupling $g_{aγγ}\,\gtrsim\,2\times10^{-14}\,\rm GeV^{-1}$, a factor of 2.7 above the benchmark KSVZ model over the mass range 23.15$\,<\,$$m_a \,$<$\,$24.0$\,μ\rm eV$. This doubles the range reported in our previous paper. We achieve a near-quantum-limited sensitivity by operating at a temperature $T<hν/2k_B$ 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.

hep-ex↗