Conveners
Axion Physics and Experiments
- Nick Houston (Beijing University of Technology)
Axion Physics and Experiments
- Nick Houston (Beijing University of Technology)
Axion Physics and Experiments
- Qiaoli Yang (Jinan University)
Axion Physics and Experiments
- Qiaoli Yang (Jinan University)
We discuss a possibility that a superconformal dynamics induces the emergence of a global U(1)PQ symmetry to solve the strong CP problem through the axion. Fields spontaneously breaking the U(1)PQ symmetry couple to new quarks charged under the ordinary color SU(3)C and a new SU(N) gauge group. The theory flows into an IR fixed point where the U(1)PQ breaking fields hold a large anomalous...
The cosmological axions/axion-like particles can compose a significant part of dark matter, however the uncertainty of their mass is large. Here we propose to search the axions broadbandly using a cylindrical capacitor, in which the static electric field converts dark matter axions into an oscillating magnetic field. A superconductor ring-coil pickup system can further boost the sensitivity....
In this talk I will present a new idea to search for axion dark matter. It is based on the backscattering of a powerful electromagnetic wave that is produced due to the stimulated decay of ambient axions. This backscattering, the echo, is a negligible (but detectable) signal with frequency spectrum centered at one half the axion mass. In the mass range where the axion is motivated to be the...
Axion-like particles (ALPs) appear in various new physics models with spontaneous global symmetry breaking. When the ALP mass is in the range of MeV to GeV, the cosmology and astrophysics bounds are so far quite weak. In this work, we investigate such light ALPs through the ALP-strahlung production process $pp \to V a (\to \gamma\gamma)$ at the 14 TeV LHC with an integrated luminosity of 3000...
We generalize the recently proposed PT-symmetric axion haloscope to a larger array with more PT-symmetric structures. The optimized signal-to-noise ratio (SNR) has a greater enhancement, as well as the signal power. Furthermore, we show that the robustness of the detector towards the variations of the array coupling is the strongest when a binary tree structure is introduced which contains a...
Solutions to the $\mu$ problem in supersymmetry based on the Kim-Nilles mechanism naturally feature a Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) axion with decay constant of order the geometric mean of the Planck and TeV scales, consistent with astrophysical limits. We investigate minimal models of this type with two gauge singlet fields that break a Peccei-Quinn symmetry, and extensions with...
In the framework where the strong coupling is dynamical, the QCD sector may confine at a much higher temperature than it would in the Standard Model, and the temperature-dependent mass of the QCD axion evolves in a non-trivial way. We find that, depending on the evolution of $\Lambda_{QCD}$, the axion field may undergo multiple distinct phases of damping and oscillation leading generically to...
In this talk, I will propose the use of the Earth as a transducer for ultralight dark-matter detection. In particular I will point out a novel signal of kinetically mixed dark-photon dark matter: a monochromatic oscillating magnetic field generated at the surface of the Earth. Similar to the signal in a laboratory experiment in a shielded box (or cavity), this signal arises because the lower...
Cosmic birefringence is predicted if an axion-like particle (ALP) moves after the recombination. We show that this naturally happens if the ALP is coupled to the dark matter density because it then acquires a large effective mass after the matter-radiation equality. We give a simple model to realize this scenario, where dark matter is made of hidden monopoles, which give the ALP such a large...
The QCD axion mass may receive contributions from small-size instantons or other Peccei-Quinn breaking effects. I show that it is possible for such a heavy QCD axion to induce slow-roll inflation if the potential is sufficiently flat near its maximum by balancing the small instanton contribution with another Peccei-Quinn symmetry breaking term. In addition, requiring the axion hilltop...
The motion of the axion field explosively produces hidden photons due to the tachyonic instability. We consider the Abelian Higgs model coupled to the hidden photon which leads to the effective mass of the Higgs. When the axion starts to oscillate and the hidden photon are produced, the Higgs is trapped by the effective mass. If the vacuum energy of the Higgs dominates the universe, then the...
We explore a novel detection possibility for solar axions, which relies only on their couplings to nucleons, via the axion-induced dissociation of deuterons into their constituent neutrons and protons. An opportune target for this process is the now-concluded Sudbury Neutrino Observatory (SNO) experiment, which relied upon large quantities of heavy water to resolve the solar neutrino problem....
We study thermal axion production around the confinement scale. At higher temperatures, we extend current calculations to account for the masses of heavy quarks, whereas we quantify produc- tion via hadron scattering at lower temperatures. Matching our results between the two opposite regimes provides us with a continuous axion production rate across the QCD phase transition. We employ such a...
Thermal axion production in the early universe goes through several mass thresholds, and the resulting rate may change dramatically across them. Focusing on the KSVZ and DFSZ frameworks for the invisible QCD axion, we perform a systematic analysis of thermal production across thresholds and provide smooth results for the rate. The QCD phase transition is an obstacle for both classes of models....
We propose a model for the QCD axion which is realized through a coupling of the Peccei-Quinn scalar field to magnetically charged fermions at high energies. We show that the axion of this model solves the strong CP problem and then integrate out heavy magnetic monopoles using the Schwinger proper time method. We find that the model discussed yields axion couplings to the Standard Model which...
Ultralight bosons behave like coherent waves when the occupation number is large enough. If they are coupled to the Standard Model sector of the particle physics, such an oscillating background can induce a tiny signal. Near a fast rotating black hole, axion within one order of the mass window can accumulate through superradiance, with a large density saturating the non-linear...
Axions and other light, weakly interacting particles might be copiously produced in stars. Can we detect them? Here I will discuss the strategies, challenges and possibilities to detect stellar axions and axion-like particles with existent and next-generation instruments.
