antimatter

Public lecture by Dr. Gerald Gabrielse

Our universe is made of matter. Yet the Big Bang produced essentially equal amounts of matter and antimatter according to our most fundamental understanding of the building blocks of nature. The inability of our fundamental theory to describe this basic feature of our universe is the great frustration of modern physics. In this one-hour lecture, held on Feb. 19, 2021, Dr. Gerald Gabrielse, Northwestern University, gives an introduction to antimatter and matter, explains the theoretical framework that explains particle interactions, and gives examples of attempts to solve the mystery of antimatter.

From Reccom Magazine, Feb. 26, 2021: Chuck Brown of the Fermilab SeaQuest research team is quoted in this piece on the sea of quarks inside the proton. The article discusses Fermilab’s contributions to the SeaQuest and NuSea experiments.

Protons are built from three quarks — two “up” quarks and one “down” quark. But they also contain a roiling sea of transient quarks and antiquarks that fluctuate into existence before swiftly annihilating one another. At the Fermilab-hosted SeaQuest experiment, researchers report that that lopsidedness persists in a realm of previously unexplored quark momenta.

From Forbes, Feb. 10, 2021: Fermilab scientist Don Lincoln explains why there should be equal amounts of matter and antimatter in the universe. There aren’t. He discusses several current theories that try to explain the discrepancy. Better understanding this imbalance is an aim of ongoing experiments, such as DUNE, which is being built at Fermilab.

From New Scientist, Jan. 25, 2021: The Big Bang left us the universe — and a major set of mysteries around antimatter, dark matter, dark energy, and cosmic inflation. While the Large Hadron Collider looks at what the laws of physics were like a trillionth of a second after the Big Bang, Dan Hooper, head of theoretical astrophysics at Fermilab, thinks the answers to these puzzles may depend on better understanding that first fraction of a second — even closer to the universe’s beginning.

Matter and antimatter particles can behave differently, but where these differences show up is still a puzzle. Scientists on the LHCb experiment at the Large Hadron Collider study much more subtle differences between matter particles and their antimatter equivalents. A recent analysis allowed them to revisit an old mystery — an asymmetry between asymmetries.

Handedness — and the related concept of chirality — are double-sided ways of understanding how matter breaks symmetries. Different-handed object pairs reveal some puzzling asymmetries in the way our universe works.

Einstein’s equation E = mc2and the theory of the Big Bang are both generally accepted physics theories, and yet, between them, they make an unphysical prediction. They predict that matter and antimatter should be observed in equal quantities. Yet the universe is made only of matter. Why is that? In this 11-minute episode of Subatomic Stories, Fermilab scientist Don Lincoln explains what is going on.