The unresolved nature of the Dark Matter permeating our Universe is one of the most pressing questions of modern science. It is connected to our very understanding of reality at the most fundamental level. The axion DM paradigm has recently emerged as one of the most compelling hypothesis to solve this question: Dark Matter would be composed by very light and very feebly interacting axions. This paradigm is strongly motivated by theory, and predicts a clear signal in terrestrial experiments called axion haloscopes. Pioneering experiments have reached enough sensitivity to test some realistic axion models in limited mass ranges, so far without a positive signal. However, there is still a large viable axion parameter space to be explored. The methods used to date will be inefficient to perform such a challenging task. Here our DarkQuantum consortium proposes a new way of addressing this gap using quantum sensing technologies and hybrid quantum systems. Specifically, we will combine quantum technologies and well established particle physics environments at CERN or DESY devoted to the detection of axions in the galactic halo. Building quantum-enhanced setups in particle physics environments is extremely challenging and needs expertise from very different fields of physics. Our consortium brings together experts from quantum circuits, very-low temperature cryogenics, quantum measurements and particle physics, to build two quantumenhanced haloscopes with unprecedented sensitivity and mass scanning range. The novel sensing strategies of the DarkQuantum project could lead to the experimental detection of axions for the first time. Such a fundamental discovery in connection with the long-standing DM problem would lead to a breakthrough in Physics
After the work developed in the last 6 years (MICAD and RADESUP projects), which have led to the design and manufacture of different haloscopes for the CAST magnet at the 8.4 GHz frequency, and the design of a haloscope in the 250 - 450 MHz band for the BabyIAXO magnet, this project has two main objectives: the fabrication and radio frequency (RF) characterization of the haloscope for BabyIAXO (which will also serve as a test bench for the gravitational wave detection study being carried out by another node of this coordinated project) and the study of improvements in high frequency haloscopes, focused on solenoid magnets, which are the usual ones in this type of detection and the type that LSC will acquire shortly.
The research team RADESUP is formed by researches from the Polytechnic University of Cartagena (UPCT) and the University of Valencia (UV). The team also includes personnel from the Conseil Européen pour la Recherche Nucléaire (CERN, Geneva, Switzerland) and from the Yebes Observatory. All of them belong to the Relic Axion Detector Exploratory Setup (RADES) team. The ultimate goal of the subproject is the detection of axion through its coupling with a strong magnetic field in a microwave resonant cavity.
We propose the study of new concepts for Dark Matter axion detection, based in the axion haloscope concept, but with RF-filter inspired geometries. This study could open new experimental lines to be applied at large-scale in IAXO in the future. For the near-term, we propose the realization of a small exploratory setup (RADES) that would be tested in the CAST magnet (activity approved by the CERN SPSC). This activity is the specific objective of one of the subprojects, with which the needed know-how, normally not present in particle physics groups, is incorportated to the community: RF cavities and filters (UPCT,UV) and low noise RF sensors (Yebes).
Pseudoscalar QCD axions and axion-like Particles (ALPs) are an excellent candidate for Dark Matter or can act as a mediator particle for Dark Matter. Since the discovery of the Higgs boson, we know that fundamental scalars exist and it is timely to explore the Axion/ALP parameter space more intensively. A look at the allowed axion/ALP parameter space makes it clear that these might exist at low mass (below few eV), as (part of) Dark Matter. Alternatively they might exist at higher mass, above roughly the MeV scale, potentially as a Dark Matter mediator particle. AxScale explores parts of these different mass regions, with complementary techniques but with one research team.
Firstly, with RADES, it develops a novel concept for a filter-like cavity for the search of QCD axion Dark matter at a few tens of a micro-eV. Dark Matter Axions can be discovered by their resonant conversion in that cavity embedded in a strong magnetic field. The `classical axion window' has recently received much interest from cosmological model-building and I will implement a novel cavity concept that will allow to explore this Dark Matter parameter region.
Secondly, AxScale searches for axions and ALPs using the NA62 detector at CERN's SPS. Especially the mass region above a few MeV can be efficiently searched by the use of a proton fixed-target facility. During nominal data taking NA62 investigates a Kaon beam. NA62 can also run in a mode in which its primary proton beam is fully dumped. With the resulting high interaction rate, the existence of weakly coupled particles can be efficiently probed. Thus, searches for ALPs from Kaon decays as well as from production in dumped protons with NA62 are foreseen in AxScale. More generally, NA62 can look for a plethora of `Dark Sector' particles with recorded and future data. With the AxScale program I aim at maximizing the reach of NA62 for these new physics models.