Concept
Baryon asymmetry refers to the observed imbalance between baryons (matter) and antibaryons (antimatter) in the universe, which is not accounted for by the Standard Model of particle physics. This asymmetry is crucial for the existence of the universe as we know it, as a perfect balance would have led to mutual annihilation, leaving behind only radiation.
Relevant Degrees
Concept
Baryogenesis is the theoretical process that attempts to explain the imbalance between matter and antimatter in the universe. It involves mechanisms that violate baryon number conservation, CP symmetry, and thermal equilibrium to produce a surplus of baryons over antibaryons after the Big Bang.
Concept
Sakharov conditions are a set of three criteria proposed by Andrei Sakharov in 1967 that are necessary for baryogenesis, the process that led to the matter-antimatter asymmetry in the universe. These conditions are baryon number violation, C and CP violation, and a departure from thermal equilibrium, all of which are essential to explain why there is more matter than antimatter in the universe today.
Concept
CP violation refers to the phenomenon where the laws of physics change when particles are replaced with their antiparticles (C symmetry) and their spatial coordinates are inverted (P symmetry). This violation is crucial in explaining the matter-antimatter asymmetry in the universe, as it allows for processes that favor matter over antimatter.
Concept
Matter-antimatter asymmetry refers to the observed imbalance between matter and antimatter in the universe, where matter vastly outnumbers antimatter despite theories suggesting they should have been created in equal amounts during the Big Bang. This asymmetry is a fundamental question in physics and has implications for understanding the evolution of the universe and the laws governing particle interactions.
Concept
The Standard Model is a fundamental theory in physics that describes the electromagnetic, weak, and strong nuclear interactions, which govern the behavior of all known subatomic particles. It successfully unifies three of the four fundamental forces of nature, but does not include gravity, and predicts the existence of particles like the Higgs boson, which was confirmed experimentally in 2012.
Concept
The cosmic microwave background (CMB) is the thermal radiation left over from the Big Bang, providing a snapshot of the infant universe approximately 380,000 years after its birth. It serves as a critical piece of evidence for the Big Bang theory and offers insights into the early universe's conditions, composition, and large-scale structure.
Concept
Leptogenesis is a theoretical framework in cosmology that explains the matter-antimatter asymmetry of the universe through the generation of an excess of leptons over antileptons in the early universe. This asymmetry is then converted into baryon asymmetry via sphaleron processes, providing a possible explanation for the observed dominance of matter over antimatter.
Concept
Electroweak baryogenesis is a theoretical framework that attempts to explain the observed asymmetry between matter and antimatter in the universe through processes occurring during the electroweak phase transition in the early universe. It suggests that conditions during this phase transition could violate CP symmetry and baryon number conservation, leading to an excess of baryons over antibaryons.
Concept
Annihilation refers to the process in which a particle and its corresponding antiparticle collide and convert their mass into energy, often in the form of photons. This phenomenon is a fundamental concept in particle physics and highlights the equivalence of mass and energy as described by Einstein's equation E=mc².
Concept
Big Bang nucleosynthesis refers to the process that occurred within the first few minutes of the universe's existence, leading to the formation of the lightest elements such as hydrogen, helium, and small amounts of lithium and beryllium. This process provides critical evidence for the Big Bang theory and helps explain the observed abundance of light elements in the universe today.
Concept
Lepton number violation refers to processes in which the total lepton number, a conserved quantum number in the Standard Model of particle physics, is not conserved. Such violations could provide insights into physics beyond the Standard Model, potentially explaining phenomena like neutrino masses and the matter-antimatter asymmetry in the universe.
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