Asia Pacific Physics Week 2024 (APPW2024)

Wednesday, Nov. 6, 2024 

3:30 PM - 4:00 PM  C. N. Yang Award Talk  Kyohei Mukaida (High Energy Accelerator Research Organization (KEK)) 

How did the hot Universe begin?

Kyohei Mukaida

Institute of Particle and Nuclear Studies, KEK

Observations of the cosmic microwave background (CMB) and light elements strongly suggest that our Universe began from an extremely hot phase, known as the Big Bang. Standard cosmology is based on the Big Bang theory, supplemented by cosmic inflation, which is the accelerated expansion phase that occurred prior to the hot Universe. This accelerated expansion phase not only resolves major issues in Big Bang cosmology but also perfectly aligns with the CMB observations. 

The energy driving this accelerated expansion must be converted into relativistic particles, including those in our Standard Model, through a process known as reheating. Understanding the reheating process is crucial for addressing the question of how our hot Universe began and may also be related to the production of other relics, such as dark matter and baryon asymmetry, both of which are necessary to explain the current Universe. 

In this talk, I will discuss my attempts to understand the reheating process and its implications.