Arch2008 said:http://www.guardian.co.uk/science/2008/apr/26/universe.physics
This says 10^-32 second after the BB.
Baryon asymmetry refers to the unequal abundance of matter and antimatter in the universe. Baryons are particles made up of three quarks, such as protons and neutrons, and their corresponding antiparticles are called anti-baryons. The existence of baryon asymmetry is a fundamental puzzle in physics, as the laws of physics suggest that matter and antimatter should have been created in equal amounts during the Big Bang.
The time of baryon asymmetry is a period in the early universe, believed to have occurred within the first few seconds after the Big Bang, where the asymmetry between matter and antimatter first appeared. This time is also referred to as the "epoch of baryogenesis".
The exact mechanism for the creation of baryon asymmetry is still unknown, but it is believed to be linked to a process called baryogenesis. This process involves violations of two fundamental symmetries in physics, known as C-symmetry (charge conjugation symmetry) and CP-symmetry (combined charge and parity symmetry). These violations could have caused a slight imbalance between matter and antimatter, resulting in the surplus of matter that we see in the universe today.
One of the main pieces of evidence for baryon asymmetry is the observed abundance of matter and antimatter in the universe. If matter and antimatter were created in equal amounts, they would have annihilated each other, leaving behind only energy. However, we see that the universe is mostly made up of matter, indicating that there was a slight excess of matter over antimatter in the early universe.
Understanding baryon asymmetry is important because it is a fundamental puzzle in physics that could provide insights into the origins and evolution of the universe. It could also help us better understand the fundamental laws of physics and potentially lead to new discoveries. Additionally, it has implications for our understanding of why the universe is made up of matter and why antimatter seems to have disappeared.