MADMAX, the MAgnetized Disc and Mirror Axion eXperiment, will use a novel dielectric haloscope concept to detect dark matter axions in a mass range around 100 mueV through axion-photon conversion in the presence of a strong magnetic field. I'll present the status of ongoing R&D on the detector design, in particular on the booster and piezo motors needed to scan the mass range. Preliminary...
The helioscope experiment BabyIAXO, which will be the predecessor of IAXO (the International AXion Observatory), poses a lot of physical challenges regarding its components. The mounting precision of magnet, optics and detector as well as physical effects like gravitation and the size of vacuum tight windows have been studied with a ray tracer based on the REST (Rare Event Searches with TPCs)...
Current results and developments for the Dark Matter halo axion search in the microwave range at the Grenoble Axion Haloscope platform will be presented.
In particular the possibilities offered by the Grenoble hybrid magnet currently under commissioning will be highlighted. These include the prospects of axion search below 500 MHz at DFSZ sensitivity, in collaboration with CAPP (GraHal-CAPP...
WISP Searches on a Fiber Interferometer (WISPFI) is a novel tabletop experiment using interferometric techniques applied to photonic crystal fibers searching for a resonant photon-axion conversion. It is independent of the local dark matter density which can highly reduce the sensitivity of axion experiments and could as well be the reason behind the null results of dark matter searches so...
Many Dark Sector models contain photon-coupled long-lived particles. An outstanding example is an axion-like particle decaying into two photons. The forward physics detectors at the LHC, e.g., FASER, were shown to be particularly suitable for hunting ~sub-GeV ALPs thanks to numerous photons produced in pp collisions, which in turn are efficiently converted into ALPs by the Primakoff...
Axions are among the best motivated candidates for new physics. If the Peccei-Quinn symmetry associated with an axion has been ever restored after inflation, axion strings form and inevitably produce a contribution to the stochastic gravitational wave background. In this talk I will discuss the resulting gravitational wave spectrum by combining effective field theory analysis with numerical...
The cosmic microwave background (CMB) holds intriguing evidence of cosmic birefringence - an isotropic rotation of the polarization direction, manifesting in the CMB's parity odd spectra. This phenomenon finds a compelling explanation within axion physics, where a light scalar field interacts with the electromagnetic field through a Chern-Simons interaction, violating parity.
In this...
Axions and axion-like particles (ALPs) are among the most popular candidates that explain the origin of the mysterious dark matter. The most popular ALP production mechanism studied in the literature is the misalignment mechanism, where an ALP field with a quadratic or cosine potential has negligible kinetic energy initially, and it starts oscillating when its mass becomes comparable to the...
In this talk I will discuss how Supernovae (SN) can be exploited to severely constrain the parameter space of axion-like-particles (ALPs) coupled to nucleons. In particular, I will provide a continuous extension of the ALPs emission rates to the case of strong nuclear couplings, in which they could enter the trapping regime. This approach allowed us to extend the usual cooling bound from the...
Ultralight bosons exhibit coherent wave behavior when their occupation number reaches a significant threshold. If these bosons interact with the Standard Model sector of particle physics, their oscillating background can generate a minute signal. In the vicinity of a rapidly rotating black hole, ultralight bosons falling within a specific mass range can accumulate via superradiance, resulting...
In axion-like dark matter cosmologies a very dense axion star forms in the center of every dark matter halo. When such axion stars are massive enough they become unstable and quickly decay via parametric resonance into radio photons. In this talk, based on 2302.10206 and 2301.09769, I will highlight the cosmological consequences of such a decay. In particular, the huge number of radio photons...
The upcoming helioscope IAXO is sensitive to realistic QCD axion models, making it one of the most exciting future axion searches. In case of a discovery, IAXO will serve as new probe of solar physics, potentially allowing us to study solar metallicities, magnetic fields, and to distinguish different solar or axion models.
To further add to this list, I will show in this talk how an “axion...
The Sun represents a particularly interesting source for keV axions since a fraction of them would be trapped into the solar gravitational field and would then accumulate over cosmic times. The decay of such trapped axions into photons would contribute to the observed X-rays coming from the Sun. The requirement that the axion-induced photons flux should not exceed the solar X-ray measurements...
Pulsar polarization arrays have the potential to probe the axion photon coupling up to ∼ $10^{-14}$ − $10^{-17}$, with a mass range ∼ $10^{-27}$ − $10^{-21}$eV. In this work, we will present the result of using the cross-correlation method to search for the stochastic axion dark matter signal in the Parkes Pulsar Timing Array data.
Nearby dwarf spheroidal galaxies are ideal targets in the search for indirect dark matter (DM) signals. In this work, we analyze MUSE spectroscopic observations of a sample of five galaxies, composed of both classical and ultra-faint dwarf spheroidals. The goal is to search for radiative decays of axion-like particles (ALPs) in the mass range of 2.7-5.3 eV. After taking into account the...
Axions and axion-like particles (ALPs) are pseudo Nambu-Goldstone bosons interacting with the SM fields via classically shift-invariant operators starting at dimension-5. Loop diagrams where the ALP is present as a virtual particle are generally UV-divergent and require renormalization. Consequently, dimension-6 SMEFT operators are generated as counterterms at the scale of global symmetry...
We present the construction of Effective Field Theories (EFTs) in which a chiral fermion, charged under both gauge and global symmetries, is integrated out via Path Integral formalism. These symmetries can be spontaneously broken, and the global ones might also be anomalous. This setting is typically served to study the structure of low-energy axion EFTs, where the anomalous global symmetry...
We present preliminary results for the QCD contribution to the axion-photon coupling obtained via lattice simulations. For sufficiently small background electromagnetic fields, the topological charge exhibits a linear response to the scalar product between E and B, whose slope can be interpreted as the axion-photon coupling. The reasons for this interpretation are explained. In order to...
Dark Matter has eluded us for decades and continues to do so. Currently lepton colliders provide exclusion limits on individual dark matter models, but many models may have either identical or indistinguishable signals. Hence there is a need for new methods or observables to determine the nature of the dark matter, especially if more than one candidate is present. Using $e^+ e^-$ processes...
Isotope shift frequencies figure among the most precisely measured physical quantities but are highly challenging to predict from first principles. In recent years King plots emerged as powerful data-driven tools that eliminate the theoretical uncertainties on the Standard Model nuclear parameters and can place bounds on new light mediators between neutrons and electrons.
We develop a...
CP-violating probes are among the most promising and yet relatively unexplored ways to look for Axion-Like Particles (ALPs) and to investigate their phenomenology. With this work we construct the most general effective Chiral Lagrangian describing the interactions of a light CP-violating ALP $\phi$ with mesons, baryons, leptons and photons at energies below the QCD confinement scale ($m_\phi...
We discuss simple scenarios where quark flavor-violating couplings generate the observed dark
matter abundance through freeze-in of an axion-like particle with mass in the few keV range. We show that these
scenarios are constrained by supernovae, structure formation and collider bounds and can be almost entirely probed by future X-ray telescopes.
We consider a model involving a visible QCD axion with mass in the MeV range with flavour non-universal couplings to the Standard Model (SM) first generation quarks and with all the SM leptons. Such a heavy axion must evade a variety of stringent constraints which precisely fix the couplings to the SM fields. While this heavy axion cannot be a Dark Matter (DM) candidate, as it decays...
Recent experimental advances further constrain electroweak-scale WIMPs produced via thermal freeze-out, leading to a shift away from this standard paradigm. Here we consider an axion-like particle (ALP), the pseudo-Goldstone boson of an approximate U(1) global symmetry spontaneously broken at a high scale fa, as a mediator between the Standard Model (SM) particles and the dark matter (DM)...
We consider models of light dark matter and light mediator, having mass of the order of a few MeV to a few GeV. In each case, the dark matter achieves relic density through mechanisms beyond the paradigm of typical freeze-in or freeze-out. The light mediators in these models, namely dark scalars, vectors or ALPs, couple to the SM particles. These interactions can be constrained by...
Ultralight dark matter (ULDM) is known to form self-gravitating bound states through relaxation of the field, through gravity or self-interactions. The canonical example is a boson star, which is self-gravitating and has been studied for decades. In this talk, I will discuss a related but distinct bound state we call a gravitational atom, which is bound by the gravitational potential of some...
Photon–axion-like particle (ALP) oscillations result in the survival of gamma rays from distant sources above TeV energies. Studies of events observed by CAST, Fermi-LAT, and IACT have constrained the ALP parameters. We investigate the effect of photon-ALP oscillations on the gamma-ray spectra of the first extragalactic neutrino source, TXS 0506+056, for observations by Fermi-LAT and MAGIC...
