arXiv subjects

G. Carosi

Publications and source records attributed to G. Carosi.

At least 19 recordsLinked to original sources

arXiv2025

Search for Axion Dark Matter from 1.1 to 1.3 GHz with ADMX

Axion dark matter can satisfy the conditions needed to account for all of the dark matter and solve the strong CP problem. The Axion Dark Matter eXperiment (ADMX) is a direct dark matter search using a haloscope to convert axions to photons in an external magnetic field. Key to this conversion is the use of a microwave resonator that enhances the sensitivity at the frequency of interest. The ADMX experiment boosts its sensitivity using a dilution refrigerator and near quantum-limited amplifier to reduce the noise level in the experimental apparatus. In the most recent run, ADMX searched for axions between 1.10-1.31 GHz to extended Kim-Shifman-Vainshtein-Zakharov (KSVZ) sensitivity. This Letter reports on the results of that run, as well as unique aspects of this experimental setup.

hep-ex↗

arXiv2025

QSHS: An Axion Dark Matter Resonant Search Apparatus

We describe a resonant cavity search apparatus for axion dark matter constructed by the Quantum Sensors for the Hidden Sector (QSHS) collaboration. The apparatus is configured to search for QCD axion dark matter, though also has the capability to detect axion-like particles (ALPs), dark photons, and some other forms of wave-like dark matter. Initially, a tuneable cylindrical oxygen-free copper cavity is read out using a low noise microwave amplifier feeding a heterodyne receiver. The cavity is housed in a dilution refrigerator and threaded by a solenoidal magnetic field, nominally 8T. The apparatus also houses a magnetic field shield for housing superconducting electronics, and several other fixed-frequency resonators for use in testing and commissioning various prototype quantum electronic devices sensitive at a range of axion masses in the range 2.0 to 40 micro-eV/c2. The apparatus as currently configured is intended as a test stand for electronics over the relatively wide frequency band attainable with the TM010 cavity mode used for axion searches. We present performance data for the resonator, dilution refrigerator, and magnet, and plans for the first science run.

physics.ins-det↗

arXiv2025

Axion Dark Matter eXperiment around 3.3 μeV with Dine-Fischler-Srednicki-Zhitnitsky Discovery Ability

We report the results of a QCD axion dark matter search with discovery ability for Dine Fischler Srednicki Zhitnitsky (DFSZ) axions using an axion haloscope. Sub-Kelvin noise temperatures are reached with an ultra low-noise Josephson parametric amplifier cooled by a dilution refrigerator. This work excludes (with a 90% confidence level) DFSZ axions with masses between 3.27 to 3.34 $μ$eV, assuming a standard halo model with a local energy density of 0.45 GeV/cm$^3$ made up 100% of axions.

hep-ex↗

arXiv2025

Revealing the loss mechanisms of a 3D superconducting microwave cavity for use in a dark matter search

Superconducting microwave cavities have found applications in many areas including quantum computing, particle accelerators, and dark matter searches. Their extremely high quality factors translate to very narrow bandwidth, which makes them key components of sensitive detectors. In this study, we aim to understand the loss mechanisms of an aluminium cavity and how they change as the cavity material transitions from the superconducting to normal state. We found that at temperatures not much lower than the transition temperature $T_c$, losses are dominated by quasiparticle excitations and are well described by the BCS theory. The exponential decrease of the quasiparticle density below $T_c$ results in a 1000-fold increase of the quality factor, as well as a shift of the resonance frequency due to the change of the kinetic inductance of the superconductor. At very low temperatures, losses due to two-level systems begin to dominate giving a peak in the quality factor of about 27.6 million at 130 mK. Understanding the loss mechanisms is invaluable, as the working temperature of the cavity may vary during operation regardless of its application.

cond-mat.supr-con↗

arXiv2025

Improved Receiver Noise Calibration for ADMX Axion Search: 4.54 to 5.41 $μ$eV

Axions are a well-motivated candidate for dark matter. The preeminent method to search for axion dark matter is known as the axion haloscope, which makes use of the conversion of axions to photons in a large magnetic field. Due to the weak coupling of axions to photons however, the expected signal strength is exceptionally small. To increase signal strength, many haloscopes make use of resonant enhancement and high gain amplifiers, while also taking measures to keep receiver noise as low as possible such as the use of dilution refrigerators and ultra low-noise electronics. In this paper we derive the theoretical noise model based on the sources of noise found within a typical axion haloscope receiver chain, using the Axion Dark Matter eXperiment (ADMX) as a case study. We present examples of different noise calibration measurements at 1280~MHz taken during ADMX's most recent data-taking run. These new results shed light on a previously unidentified interaction between the cavity and JPA, as well as provide a better understanding of the systematic uncertainty on the system noise temperature used in the axion search analysis for this data-taking run. Finally, the consistency between the measurements and the detailed model provide suggestions for future improvements within ADMX and other axion haloscopes to reach a lower noise temperature.

hep-ex↗

arXiv2024

Search for non-virialized axions with 3.3-4.2 $μ$eV mass at selected resolving powers

The Axion Dark Matter eXperiment is sensitive to narrow axion flows, given axions compose a fraction of the dark matter with a non-negligible local density. Detecting these low-velocity dispersion flows requires a high spectral resolution and careful attention to the expected signal modulation due to Earth's motion. We report an exclusion on the local axion dark matter density in narrow flows of $ρ_a \gtrsim 0.03\,\mathrm{GeV/cm^3}$ and $ρ_a \gtrsim 0.004\,\mathrm{GeV/cm^3}$ for Dine-Fischler-Srednicki-Zhitnitski and Kim-Shifman-Vainshtein-Zakharov axion-photon couplings, respectively, over the mass range $3.3-4.2\,μ\text{eV}$. Measurements were made at selected resolving powers to allow for a range of possible velocity dispersions.

astro-ph.CO↗

arXiv2024

First Results from a Broadband Search for Dark Photon Dark Matter in the $44$ to $52\,μ$eV range with a coaxial dish antenna

We present first results from a dark photon dark matter search in the mass range from 44 to 52 $μ{\rm eV}$ ($10.7 - 12.5\,{\rm GHz}$) using a room-temperature dish antenna setup called GigaBREAD. Dark photon dark matter converts to ordinary photons on a cylindrical metallic emission surface with area $0.5\,{\rm m}^2$ and is focused by a novel parabolic reflector onto a horn antenna. Signals are read out with a low-noise receiver system. A first data taking run with 24 days of data does not show evidence for dark photon dark matter in this mass range, excluding dark photon - photon mixing parameters $χ\gtrsim 10^{-12}$ in this range at 90% confidence level. This surpasses existing constraints by about two orders of magnitude and is the most stringent bound on dark photons in this range below 49 $μ$eV.

hep-ex↗

arXiv2023

Axion Dark Matter eXperiment: Run 1A Analysis Details

The ADMX collaboration gathered data for its Run 1A axion dark matter search from January to June 2017, scanning with an axion haloscope over the frequency range 645-680 MHz (2.66-2.81 ueV in axion mass) at DFSZ sensitivity. The resulting axion search found no axion-like signals comprising all the dark matter in the form of a virialized galactic halo over the entire frequency range, implying lower bound exclusion limits at or below DFSZ coupling at the 90% confidence level. This paper presents expanded details of the axion search analysis of Run 1A, including review of relevant experimental systems, data-taking operations, preparation and interpretation of raw data, axion search methodology, candidate handling, and final axion limits.

hep-ex↗

arXiv2023

Non-Virialized Axion Search Sensitive to Doppler Effects in the Milky Way Halo

The Axion Dark Matter eXperiment (ADMX) has previously excluded Dine-Fischler-Srednicki-Zhitnisky (DFSZ) axions between 680-790 MHz under the assumption that the dark matter is described by the isothermal halo model. However, the precise nature of the velocity distribution of dark matter is still unknown, and alternative models have been proposed. We report the results of a non-virialized axion search over the mass range 2.81-3.31 μeV, corresponding to the frequency range 680-800 MHz. This analysis marks the most sensitive search for non-virialized axions sensitive to Doppler effects in the Milky Way Halo to date. Accounting for frequency shifts due to the detector's motion through the Galaxy, we exclude cold flow relic axions with a velocity dispersion of order 10^-7 c with 95% confidence.

astro-ph.CO↗

arXiv2023

Search for a dark-matter induced Cosmic Axion Background with ADMX

We report the first result of a direct search for a Cosmic ${\it axion}$ Background (C$a$B) - a relativistic background of axions that is not dark matter - performed with the axion haloscope, the Axion Dark Matter eXperiment (ADMX). Conventional haloscope analyses search for a signal with a narrow bandwidth, as predicted for dark matter, whereas the C$a$B will be broad. We introduce a novel analysis strategy, which searches for a C$a$B induced daily modulation in the power measured by the haloscope. Using this, we repurpose data collected to search for dark matter to set a limit on the axion photon coupling of a C$a$B originating from dark matter cascade decay via a mediator in the 800-995 MHz frequency range. We find that the present sensitivity is limited by fluctuations in the cavity readout as the instrument scans across dark matter masses. Nevertheless, we suggest that these challenges can be surmounted using superconducting qubits as single photon counters, and allow ADMX to operate as a telescope searching for axions emerging from the decay of dark matter. The daily modulation analysis technique we introduce can be deployed for various broadband RF signals, such as other forms of a C$a$B or even high-frequency gravitational waves.

hep-ex↗

arXiv2023

Axion Dark Matter

Axions are well-motivated dark matter candidates with simple cosmological production mechanisms. They were originally introduced to solve the strong CP problem, but also arise in a wide range of extensions to the Standard Model. This Snowmass white paper summarizes axion phenomenology and outlines next-generation laboratory experiments proposed to detect axion dark matter. There are vibrant synergies with astrophysical searches and advances in instrumentation including quantum-enabled readout, high-Q resonators and cavities and large high-field magnets. This white paper outlines a clear roadmap to discovery, and shows that the US is well-positioned to be at the forefront of the search for axion dark matter in the coming decade.

hep-ex↗

arXiv2023

Low Frequency (100-600 MHz) Searches with Axion Cavity Haloscopes

We investigate reentrant and dielectric loaded cavities for the purpose of extending the range of axion cavity haloscopes to lower masses, below the range where the Axion Dark Matter eXperiment (ADMX) has already searched. Reentrant and dielectric loaded cavities were simulated numerically to calculate and optimize their form factors and quality factors. A prototype reentrant cavity was built and its measured properties were compared with the simulations. We estimate the sensitivity of axion dark matter searches using reentrant and dielectric loaded cavities inserted in the existing ADMX magnet at the University of Washington and a large magnet being installed at Fermilab.

hep-ph↗

arXiv2022

ADMX-Orpheus First Search for 70 $μ$eV Dark Photon Dark Matter: Detailed Design, Operations, and Analysis

Dark matter makes up 85% of the matter in the universe and 27% of its energy density, but we do not know what comprises dark matter. It is possible that dark matter may be composed of either axions or dark photons, both of which can be detected using an ultra-sensitive microwave cavity known as a haloscope. The haloscope employed by ADMX consists of a cylindrical cavity operating at the TM$_{010}$ mode and is sensitive to the QCD axion with masses of few $μ$eV. However, this haloscope design becomes challenging to implement for higher masses. This is because higher masses require smaller-diameter cavities, consequently reducing the detection volume which diminishes the detected signal power. ADMX-Orpheus mitigates this issue by operating a tunable, dielectrically-loaded cavity at a higher-order mode, allowing the detection volume to remain large. This paper describes the design, operation, analysis, and results of the inaugural ADMX-Orpheus dark photon search between 65.5 $μ$eV (15.8 GHz) and 69.3 $μ$eV (16.8 GHz), as well as future directions for axion searches and for exploring more parameter space.

hep-ex↗

arXiv2022

Search for 70 μeV Dark Photon Dark Matter with a Dielectrically-Loaded Multi-Wavelength Microwave Cavity

Microwave cavities have been deployed to search for bosonic dark matter candidates with masses of a few $μ$eV. However, the sensitivity of these cavity detectors is limited by their volume, and the traditionally-employed half-wavelength cavities suffer from a significant volume reduction at higher masses. ADMX-Orpheus mitigates this issue by operating a tunable, dielectrically-loaded cavity at a higher-order mode, which allows the detection volume to remain large. The ADMX-Orpheus inaugural run excludes dark photon dark matter with kinetic mixing angle $χ> 10^{-13}$ between 65.5 $μ$eV (15.8 GHz) and 69.3 $μ$eV (16.8GHz), marking the highest-frequency tunable microwave cavity dark matter search to date.

hep-ex↗

arXiv2022

Multi-mode Analysis of Surface Losses in a Superconducting Microwave Resonator in High Magnetic Fields

This paper reports on a surface impedance measurement of a niobium titanium superconducting radio frequency (SRF) cavity in a magnetic field (up to $10\,{\rm T}$). A novel method is employed to decompose the surface resistance contributions of the cylindrical cavity end caps and walls using measurements from multiple $TM$ cavity modes. The results confirm that quality factor degradation of a NbTi SRF cavity in a high magnetic field is primarily from surfaces perpendicular to the field (the cavity end caps), while parallel surface resistances (the walls) remain relatively constant. This result is encouraging for applications needing high Q cavities in strong magnetic fields, such as the Axion Dark Matter eXperiment (ADMX), because it opens the possibility of hybrid SRF cavity construction to replace conventional copper cavities.

physics.acc-ph↗

arXiv2022

New Horizons: Scalar and Vector Ultralight Dark Matter

The last decade has seen unprecedented effort in dark matter model building at all mass scales coupled with the design of numerous new detection strategies. Transformative advances in quantum technologies have led to a plethora of new high-precision quantum sensors and dark matter detection strategies for ultralight ($<10\,$eV) bosonic dark matter that can be described by an oscillating classical, largely coherent field. This white paper focuses on searches for wavelike scalar and vector dark matter candidates.

hep-ex↗

arXiv2021

Search for "Invisible" Axion Dark Matter in the $3.3\text{-}4.2~μ$eV Mass Range

We report the results from a haloscope search for axion dark matter in the $3.3\text{-}4.2~μ$eV mass range. This search excludes the axion-photon coupling predicted by one of the benchmark models of "invisible" axion dark matter, the KSVZ model. This sensitivity is achieved using a large-volume cavity, a superconducting magnet, an ultra low noise Josephson parametric amplifier, and sub-Kelvin temperatures. The validity of our detection procedure is ensured by injecting and detecting blind synthetic axion signals.

hep-ex↗

arXiv2021

Dark Matter Axion Search Using a Josephson Traveling Wave Parametric Amplifier

We present a new exclusion bound of axion-like particle dark matter with axion-photon couplings above $\mathrm{10^{-13}}$ $\mathrm{GeV^{-1}}$ over the frequency range 4796.7--4799.5 MHz, corresponding to a narrow range of axion masses centered around 19.84 $μ$eV. This measurement represents the first implementation of a Josephson Traveling Wave Parametric Amplifier (JTWPA) in a dark matter search. The JTWPA was operated in the insert of the Axion Dark Matter eXperiment (ADMX) as part of an independent receiver chain that was attached to a 0.588-liter cavity. The ability of the JTWPA to deliver high gain over a wide (3 GHz) bandwidth has engendered interest from those aiming to perform broadband axion searches, a longstanding goal in this field.

hep-ex↗