A dark matter telescope probing the 6 to 60 GHz band

Abstract

In this article we present the Dark-photons&Axion-Like particles Interferometer (DALI), a novel experiment designed for the detection of photon-mixing cold dark matter in the microwave band between 6 and 60 GHz. DALI is a haloscope for the simultaneous search for axions, axion-like particles and dark photons, with a number of novelties that make it unique. First, it is a dark matter telescope, with a capacity for pointing, tracking and rastering objects and areas in the sky. This potentially allows one to detect relativistic dark matter particles, substructures and flows, without compromising the simultaneous scanning for dark matter relic particles present in the laboratory. Second, it has been designed using commercial technology. This will allow feasible manufacture at a reasonable cost, thereby mitigating the need for R&D and facilitating maintenance. Finally, it benefits from a high sensitivity over a broad band of frequencies with only minimal reconfiguration.

Superdense beaming of axion dark matter in the vicinity of the light cylinder of pulsars

“…The direct detection of neutron star axions at the Earth position by dark matter halohelio-tele-scopes [64,80,81] is an interesting question. Relativistic aberration transforms the regular semi-isotropic dipole pattern of radio-emission into a narrower beam of light JCAP08(2022)026 with a high directionality in the observer's line-of-sight.…”

Superdense beaming of axion dark matter in the vicinity of the light cylinder of pulsars

“…The direct detection of neutron star axions at the Earth position by dark matter halohelio-tele-scopes [57,66,67] is an interesting question. Relativistic aberration transforms the regular semi-isotropic dipole pattern of radio-emission into a narrower beam of light with a high directionality in the observer's line-of-sight.…”

Experimental measurement of the quality factor of a Fabry-Pérot open-cavity axion haloscope

“…Interestingly, a higher relative permittivity, 𝜀 𝑟 , results in a higher peak at the expense of a narrower full width at half maximum of the Lorentzian spectral feature originating from interferometry. An instantaneous scanning bandwidth of several dozens of megahertz with a quality factor of the order of 𝑄 ∼ 10 4 is aimed for in this implementation to render the weak signal originating from axion-to-photon conversion detectable in a reasonable acquisition time, which is tenable according to simulations [13]. The aim of this work is to verify experimentally the quality factor provided by a resonator made of multiple ceramic layers.…”

“…Here, embedding grains or wires of a superconducting metal in a material transparent to microwave radiation provides the desired inhomogeneity of the magnetic field that enables the search for axion. Intended to perform a tunable broad band scan for axion at high-frequency, the Dark-photons & Axion-Like particles Interferometer (DALI) [13,14] incorporates a Fabry-Pérot (FP) resonator, composed of ceramic layers, instead of a resonant cavity, or rather than superconducting wire planes as adopted in Sikivie's approach. This set-up can extend the quest for the axion to a range of masses which remains poorly explored, in part since in the Sikivie's cavity-haloscope the resonant frequency, 𝜈 0 , scales inversely on size, or the distance between the movable dielectric rods used for tuning, 𝑑, in the form 𝜈 0 ∼ 𝑐/𝑑, 𝑐 being the speed of light; while the coherence volume, which boosts the output power, decreases accordingly, lowering the sensitivity.…”