Michigan: The Axion Solves Three Mysteries of the Universe

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Michigan: The Axion Solves Three Mysteries of the Universe

Post by bystander » Tue Mar 10, 2020 5:31 pm

The Axion Solves Three Mysteries of the Universe
University of Michigan, Ann Arbor | 2020 Mar 10
A hypothetical particle called the axion could solve one of physics’ great mysteries: the excess of matter over antimatter, or why we’re here at all.

According to the Standard Model of particle physics, when our universe was born, the meeting of matter and antimatter should have annihilated each other. That means that nothing—no Earth, no sun, no galaxies, no humans—would exist. But we do.

“There’s a clear contradiction with the Standard Model,” said ... Raymond Co. “Why is the whole universe filled with matter, and very, very little antimatter?”

The Standard Model of particle physics explains three fundamental forces in the universe: electromagnetism, the weak force, and the strong force. Electromagnetism is the force between any particles that have a charge. The weak force causes neutrons to break down, and the strong force explains why subatomic particles such as neutrons and protons hold together.

But there are a few contradictions within the Standard Model, one of them being the imbalance between matter and antimatter. The Standard Model also does not explain the existence of dark matter, nor does it explain an observed property of neutrons.

To solve the neutron problem, physicists in 1977 proposed a hypothetical particle called the axion. Five years later, the axion was found capable of solving the problem of dark matter as well. Now, Co and co-author Keisuke Harigaya ... are suggesting that the axion may explain yet another problem: the imbalance between matter and antimatter. ...

Paper Sheds Light on Infant Universe and Origin of Matter
Institute for Advanced Study, Princeton | 2020 Mar 10

Axiogenesis ~ Raymond T. Co, Keisuke Harigaya
Last edited by bystander on Fri Jun 26, 2020 9:23 pm, edited 1 time in total.
Reason: Updated links on Axiogenesis paper
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IAS: Case for Axion Origin of Dark Matter Gains Traction

Post by bystander » Fri Jun 26, 2020 9:36 pm

Case for Axion Origin of Dark Matter Gains Traction
Institute for Advanced Study, Princeton | 2020 Jun 26
In a new study of axion motion, researchers propose a scenario known as “kinetic misalignment” that greatly strengthens the case for axion/dark matter equivalence. The novel concept answers key questions related to the origins of dark matter and provides new avenues for ongoing detection efforts. ...

The existence of dark matter has been confirmed by several independent observations, but its true identity remains a mystery. According to this study, axion velocity provides a key insight into the dark matter puzzle. Previous research efforts have successfully accounted for the abundance of dark matter in the universe; however certain factors, such as the underproduction of axions with stronger ordinary matter interactions, remained unexplored.

By assigning a nonzero initial velocity to the axion field, the team discovered a mechanism -- termed kinetic misalignment -- producing far more axions in the early universe than conventional mechanisms. The motion, generated by breaking of the axion shift symmetry, significantly modifies the conventional computation of the axion dark matter abundance. Additionally, these dynamics allow axion dark matter to react more strongly with ordinary matter, exceeding the prediction of the conventional misalignment mechanism.

Axion Kinetic Misalignment Mechanism ~ Raymond T. Co et al
Axion Kinetic Misalignment and Parametric Resonance from Inflation ~ Raymond T. Co et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor