We use the scattering method to calculate the gravitational wave from axions annihilation in the axion cloud formed by the superradiance process around the Kerr black hole. We consider axions annihilating to gravitons as a three-body decay process and then calculate the corresponding decay width. In this approach, we can simply obtain the radiation power of gravitational wave and give the analytical approximate result with the spin effects of the Kerr black hole. Our study can also provide a cross-check to the numerical results in the traditional method.

China

Jing Yang

Fa Peng Huang

Gravitational waves from axions annihilation through quantum field theory

Motivated by current status of dark matter (DM) search, a new type of DM production mechanism is proposed based on the dynamical process of a strong first-order phase transition in the early Universe, namely, the filtered DM mechanism. We study the hydrodynamic effects on the DM relic density. By detailed calculations, we demonstrate that the hydrodynamic modes with the corresponding hydrodynamic heating effects play essential roles in determining the DM relic density. The corresponding phase transition gravitational wave could help to probe this new mechanism.

Siyu Jiang

Chong Sheng Li

Hydrodynamic effects on the filtered dark matter produced by a first-order phase transition

The bubble wall velocity is essential for the spectra of phase-transition gravitational waves, electroweak baryogenesis and the dynamical dark matter mechanism. We perform detailed calculations of the bubble wall velocity in the well-motivated inert doublet model using the microphysical approach with some recent new methods.

Xiao Wang

Bubble wall velocity during electroweak phase transition in the inert doublet model

We study how to unravel the dark matter blind spots by phase transition gravitational waves in synergy with collider signatures at electroweak one-loop level taking the inert doublet model as an example. We perform a detailed Monte Carlo study at the future lepton colliders in the favored parameter space, which is consistent with current dark matter experiments and collider constraints. Our studies demonstrate that the Circular Electron Positron Collider and other future lepton colliders have the potential to explore the dark matter blind spots.

Yan Wang

United States

Complementary probe of dark matter blind spots by lepton colliders and gravitational waves

The Dark photon as an ultralight dark matter candidate can interact with the standard model particles via kinetic mixing. We propose to search for the ultralight dark photon dark matter using radio telescopes with solar observations. The dark photon dark matter can efficiently convert into photons in the outermost region of the solar atmosphere, the solar corona, where the plasma mass of photons is close to the dark photon rest mass. Because of the strong resonant conversion and benefiting from the short distance between the Sun and the Earth, the radio telescopes can lead the dark photon search sensitivity in the mass range of <math><mn>4</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>8</mn></mrow></msup><mi>–</mi><mn>4</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>, corresponding to the frequency 10–1000 MHz. As a promising example, the low-frequency array telescope can reach the kinetic mixing <math><mi>ε</mi><mo>∼</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup></math> (<math><msup><mn>10</mn><mrow><mo>−</mo><mn>14</mn></mrow></msup></math>) within 1 (100) h of solar observations. The future experiment square kilometer array phase 1 can reach <math><mrow><mi>ε</mi><mo>∼</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>16</mn></mrow></msup><mi>–</mi><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup></mrow></math> with 1 h of solar observations.

Haipeng An

Jia Liu

Wei Xue

Radio-frequency Dark Photon Dark Matter across the Sun

Extra <math><mi>C</mi><mi>P</mi></math>-violating source for electroweak baryogenesis can dynamically appear at finite temperature in the complex two-Higgs doublet model, which might help to alleviate the strong constraints from the electric dipole moment experiments. In this scenario, we study the detailed phase transition dynamics and the corresponding gravitational wave signals in synergy with the collider signals at future lepton colliders. For some parameter spaces, various phase transition patterns can occur, such as the multistep phase transition and supercooling. Gravitational waves complementary to collider signals can help to pin down the underlying phase transition dynamics or different phase transition patterns.

Xinmin Zhang

Gravitational wave and collider signals in complex two-Higgs doublet model with dynamical <math><mi>C</mi><mi>P</mi></math>-violation at finite temperature

We study phenomenological consequences of the strong first-order electroweak phase transition in an extension of the standard model with an inert doublet and vectorlike leptons motivated by the muon <math><mi>g</mi><mo>−</mo><mn>2</mn></math> anomaly and dark matter. We find that a condition for the strong first-order electroweak phase transition inevitably induces a large logarithmic enhancement in <math><mi>Z</mi></math> boson decays, which relegates the explanation of the anomalous muon <math><mi>g</mi><mo>−</mo><mn>2</mn></math> at below <math><mrow><mn>2</mn><mi>σ</mi></mrow></math> level. Our analysis shows that future lepton collider experiments, especially the Giga-<math><mrow><mi>Z</mi></mrow></math> at the International Linear Collider and Tera-<math><mrow><mi>Z</mi></mrow></math> at the Circular Electron Positron Collider as well as Future Circular Collider have great capability to explore the nature of the electroweak phase transition, which is complementary to conventional approaches via measurements of the triple Higgs boson coupling and gravitational waves.

South Korea

Eibun Senaha

Enhanced <math><mrow><mi>Z</mi></mrow></math> boson decays as a new probe of first-order electroweak phase transition at future lepton colliders

Taking the 3-3-1 models (with <math><mi>S</mi><mi>U</mi><msub><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow><mrow><mi>c</mi></mrow></msub><mo>⊗</mo><mi>S</mi><mi>U</mi><msub><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow><mrow><mi>L</mi></mrow></msub><mo>⊗</mo><mi>U</mi><msub><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow><mrow><mi>Y</mi></mrow></msub></math> gauge group) as examples, we study that a class of new physics models with extended gauge group could undergo one or several first-order phase transitions associated with the spontaneously symmetry breaking processes during the evolution of the universe, which can produce detectable phase transition gravitational wave (GW) signals at future GW experiments, such as LISA, BBO, DECIGO, SKA and aLIGO. These GW signals can provide new sources of GWs with different peak frequencies, and can be used to probe the evolution history of the universe.

Probing the gauge symmetry breaking of the early universe in 3-3-1 models and beyond by gravitational waves

Motivated by the absence of dark matter signals in direct detection experiments and the discovery of gravitational waves (GWs) at aLIGO, we discuss the possibility to explore a generic classes of scalar dark matter models using the complementary searches via phase transition GWs and the future lepton collider signatures. We focus on the inert scalar multiplet dark matter models and the mixed inert scalar dark matter models, which could undergo a strong first-order phase transition during the evolution of the early universe, and might produce detectable phase transition GW signals at future GW experiments, such as LISA, DECIGO and BBO. We find that the future GW signature, together with the collider signature at future lepton collider, could further explore the model’s blind spot parameter region, at which the dark matter-Higgs coupling is identically zero, thus avoiding the dark matter spin-independent direct detection constraints.

Jiang-Hao Yu

Exploring inert dark matter blind spots with gravitational wave signatures

By assuming a dynamical source of <math><mi>C</mi><mi>P</mi></math> violation, the tension between sufficient <math><mi>C</mi><mi>P</mi></math> violation for successful electroweak baryogenesis and strong constraints from current electric dipole moment measurements could be alleviated. We study how to explore such scenarios through gravitational wave detection, collider experiments, and their possible synergies with a well-studied example.