We discuss the PQ-quality and the possible hierarchical patterns of axion scales (and couplings) for extra-dimensional axions that originate from higher-dimensional p-form gauge fields. As a concrete example, we consider a 5-dim model on Z2-orbifold involving 1-form and 3-form gauge fields, and examine how the warped geometry and fixed-point interactions affect the PQ-quality and axion scale...
We construct a model of the quintessence axion based on a gauged chiral U(1) symmetry and an additional flat fifth dimension. The required high qualities are guaranteed by the brane separation. The observed cosmological constant (i.e., the potential energy of the quintessence axion) is determined by the size of the extra dimension and the axion decay constant F_a is fixed almost at F_a ≃ 10^17...
Searching for Solar and Reactor Axions with XENONnT and RELICS
Axions can be produced in the Sun through processes such as inverse Compton scattering, the Primakoff effect, and the Fe57 deexcitation, and detected in noble liquid experiments via the inverse Primakoff effect and the axio-electric effect. Liquid xenon experiments, with their large exposure, low background, and low-energy...
The dark photon is a well motivated candidate for the dark matter. A primary tool in this search is the cavity haloscope, which facilitates resonantly enhanced conversion to photons from dark photons. We re-examining the data taken by the Taiwan Axion Search Experiment with Haloscope (TASEH) experiment, and derive a world-leading constraint on the dark photon with mass in the 19.46 - 19.84...
Gravitational wave (GW) birefringence is a remarkable phenomenon which provides a window to test partiy violation in gravity. In this talk, I would discuss our recent studies on the GW birefringence in the FDM and symmetron models. In particular, inspired by the complicated distributions of the Fuzzy dark matter (FDM) and the symmetron field in our Galaxy, we are led to considering the GW...
We present a new framework of grand unification that is equipped with an axion solution to the strong CP problem without a domain wall problem when the Peccei–Quinn (PQ) symmetry is spontaneously broken after inflation. Our grand unified theory (GUT) is based on a symmetry breaking pattern, SU(10) × SU(5)1 → SU(5)V ⊃ SU(3)C × SU(2)L × U(1)Y, where SU(5)1 and a special embedding of SU(5)2 ⊂...
The hot interiors of massive stars in the later stages of their evolution provide an ideal place for the production of heavy axion-like particles (ALPs) with mass up to O(100 keV) range. We show that a fraction of these ALPs could stream out of the stellar photosphere and subsequently decay into two photons that can be potentially detected on or near the Earth. In particular, we estimate the...
The preferred axion models are a set of minimal QCD axion models that abide by standard cosmological constraints in the post-inflationary PQ breaking scenario. It turns out that some of these models predict a period of early matter domination, driven by the additional particle content. I will discuss how this leads to a greater number of models with consistent cosmologies and alters the axion...
Rotating primordial black holes (PBHs) in the early universe can emit particles through superradiance, a process particularly efficient when the particle's Compton wavelength is comparable to the PBH's gravitational radius. Superradiance leads to an exponential growth of particle occupation numbers in gravitationally bound states. We present an analysis of heavy bosonic dark matter (DM)...
DarkSHINE is a fixed-target experiment initiative to search for light Dark Matter and mediators at SHINE (Shanghai high repetition rate XFEL and extreme light facility, being the 1st hard X-ray FEL in China) under construction targeting completion in 2025/2026. DarkSHINE aims to search for the new mediator, Dark Photon, bridging the Dark sector and the ordinary matter. In this contribution, we...
The axion is particularly well motivated candidate for the dark matter comprising most of the mass of our visible Universe, leading to worldwide experimental and observational efforts towards its discovery. A primary technique in this search is the cavity haloscope, which is used to enhance the rate that dark matter axions convert to photons in a background electromagnetic field. As we...
We derive new constraints on millicharged dark matter from the multimessenger observation of GW170817. In the neutron star merger event GW170817, the first detection of a gamma-ray burst (GRB) delayed by approximately 1.7 seconds relative to the gravitational wave emission was observed. Utilizing this delay, we constrain the millicharge parameter of dark matter within the large-scale structure...
In this talk, I will present the latest results from the Fermilab Muon g-2 experiment and the current status of the PSI muEDM experiment. I will also discuss how these muon storage experiments can be used to search for new particles, such as axions.
We show that scalar perturbations in the early universe could produce a significant amount of these particles primarily through mass parametric resonance effects. Notably, this mechanism does not generate additional isocurvature perturbations.
We present a detailed phenomenological study of a light dilaton $\varphi$, arising from the spontaneous breaking of approximate scale invariance in a nearly conformal theory. Particular care is taken to account for the dilaton’s enhanced coupling to photons, originating from loops of the conformal sector, which significantly shortens its lifetime and relaxes constraints from $K \to \pi + {\rm...
Though most axion dark matter experiments use static background fields, the axion also induces transitions between oscillating modes of an excited cavity. This "heterodyne" detection approach benefits from the very high quality factors available in superconducting cavities, and has a parametrically enhanced signal power at low axion masses. I will review recent experimental progress on this...
QCD axion can explain the strong CP problem and dark matter (DM) simultaneously. If the Peccei-Quinn (PQ) symmetry is spontaneously broken after inflation, string-wall network would dominate the energy density in the Universe. In this talk, we consider a mixing coupling of the PQ scalar with a light scalar field which induces an extra axion potential. When the PQ scalar is mixed nonlinearly,...
Constraints on axions as hot dark matter (HDM) from $\Delta N_{\rm eff}$ provide an important and independent probe of axion properties. In hadronic axion models such as the KSVZ model, the axion thermalization rate below the QCD crossover temperature is typically estimated under two key assumptions: (1). thermal corrections to the reaction amplitudes are negligible at $T < M_{\rm th}/2$ with...
Ultralight charged bosons can extract energy, angular momentum, and charge from a Kerr–Newman black hole (BH) due to superradiant instability, resulting in the formation of a BH–condensate system. In this work, we focus on a scalar field with a minicharge and numerically investigate in detail the evolution of this system. We find that even a tiny initial mass asymmetry between the positively...
As an alternative theory to cold dark matter (CDM), fuzzy dark matter (FDM) has recently attracted widespread attention. FDM consists of ultra-light bosons with masses around 10^{-22} eV. At typical galactic velocities, their de Broglie wavelength can reach kiloparsec (kpc) scales, thereby exhibiting unique wave-like behavior on galactic scales. This leads to complex evolutionary dynamics and...
Superconducting radio-frequency (SRF) cavities, renowned for their exceptionally high quality factors (~10^10), have emerged as powerful tools for probing fundamental physics beyond the Standard Model. In this talk, I will introduce the first-ever scan search for dark photon dark matter using a tunable SRF cavity, achieving unprecedented sensitivity to the kinetic mixing coefficient parameter...
I will present a composite dark matter framework based on the confinement dynamics of a dark SU(N) Yang-Mills sector. This theory gives rise to composite bound states, glueballs, that in the absence of fermions serve as dark matter candidates. I will review recent developments in understanding glueball production in the early Universe and delineate the parameter space where they can account...
Haloscoope experiment, with the assumption that the Dark Matter is completely made of Axions, provides the highest Axion search sensitivity. The TASEH experiment is a Haloscope experiment with a copper coated stainless steel cavity inside a 9T magnet in a Dilution Refrigerator operating at 50 mK base temperature. An amplification chain with a self-developed Josephson Parametric Amplifier has...
In this talk I propose a laser-assisted method for the search of light dark particles such as axion-like particle and dark photon. I will first introduce strong-field QED framework and laser-assisted Compton scattering. Then I will discuss the laser-induced Compton scattering to dark particles and show the prospect of detection.
