Workshop on Very Light Dark Matter 2023

Session

Afternoon session-1

Mar 28, 2023, 2:00 PM

Mario Royal Kaikan (Chino, Nagano) + Online

Conveners

Afternoon session-1

• Tomohiro Fujita

Afternoon session-1

• Wen Yin

12. The evolution of domain wall network with inflationary fluctuations under the asymmetric potential

Junseok Lee

3/28/23, 2:00 PM

Domain wall networks can induce cosmological problems. Previous work has shown that networks with initial inflationary fluctuations are long-lived despite being under population bias. This is due to large scale correlations, which cannot be seen in white noise case. However, the fate of these networks under potential bias is not well-understood. In our research, we investigate the time...

11. Weak lensing and cosmic birefringence

Fumihiro Naokawa

3/28/23, 2:20 PM

Cosmic birefringence a newly reported signal from CMB and promising probe for new physics. In this talk, I am going to talk about weak lensing correction to Cosmic Birefringence signal. It will be important to use highly improved data by next generated CMB observations in the near future.

13. Cosmic birefringence tomography with late-time polarization signals

Toshiya Namikawa

3/28/23, 2:40 PM

In this presentation, I consider polarization signals after the reionization epoch to constrain rotation angles of CMB polarization plane for the cosmic birefringence tomography. The late-time polarization signals, the so-called polarized SZ (pSZ) effect, arises in the process of the scattering of the cosmic microwave background (CMB) photons off the electrons. The pSZ signals can be...

30. Axion Dark Matter from Frictional Misalignment

Alexandros Papageorgiou

3/29/23, 4:30 PM

We study the impact of sphaleron-induced thermal friction on the axion dark-matter abundance due to the interaction of an axion-like particle (ALP) with a dark non-abelian gauge sector in a secluded thermal bath. Thermal friction can either enhance the axion relic density by delaying the onset of oscillations or suppress it by damping them. We derive an analytical formula for the frictional...

22. Hybrid inflation driven by QCD axion

Yuma Narita

3/29/23, 5:10 PM

Inflation plays a central role in modern cosmology. In order to reheat the Universe, inflaton must couple to the Standard Model particles, including gluons. Meanwhile, the QCD axion may couple to gluons to solve the strong CP problem. In this study, we investigate the inflationary scenario involving a QCD axion and a scalar field coupled to gluons. We find that this scenario can solve the...