Muon physics: Have we found a new force of nature? | Alex Keshavarzi | TEDxManchester
TLDRThis talk explores three major mysteries in particle physics: the accelerating expansion of the universe attributed to dark energy, the presence of dark matter, and the matter-antimatter asymmetry. It introduces the Standard Model of particle physics and highlights the role of the muon in potentially discovering new particles or forces. The Muon g-2 experiment at Fermilab has found discrepancies in the muon's wobbling behavior, suggesting the existence of unknown forces or particles. The results are promising, with a 99.9975% chance of new discoveries, but further research is needed to confirm these findings.
Takeaways
- 🌌 The universe is expanding from the Big Bang and its expansion is accelerating, not slowing down as expected.
- 🌑 Dark energy, an unknown force, is causing the universe's accelerated expansion and makes up about 74% of the universe's energy content.
- 🌚 Dark matter, unseen and undetected on Earth, makes up approximately 21% of the universe's energy content and is crucial for the gravitational effects observed in galaxies.
- 🤔 Matter and antimatter should have been created in equal amounts during the Big Bang, yet the universe is predominantly composed of matter, with an apparent asymmetry.
- 🔬 The Standard Model of particle physics is a well-tested theory that explains the known particles and forces but does not account for dark energy, dark matter, or the matter-antimatter asymmetry.
- 🧲 The muon, a heavy cousin of the electron, is used in experiments to search for new particles and forces by measuring its wobble in a magnetic field.
- 🌀 The muon g-2 experiment at Fermilab aims to measure the wobble of muons to an unprecedented precision to detect any deviations from the Standard Model predictions.
- 📊 The muon g-2 experiment's results suggest that muons wobble faster than predicted by the Standard Model, indicating a possible new particle or force.
- 🚀 The chance that the muon g-2 experiment's result is a statistical fluke is extremely low (one in forty thousand), suggesting a strong indication of new physics.
- ⚠️ While the results are exciting, they have not yet reached the 'discovery threshold' of one in 3.5 million, meaning no definitive discovery has been claimed.
- 🔮 The muon g-2 experiment will continue to provide insights into the fundamental nature of the universe and may help solve the mysteries of dark energy, dark matter, and the matter-antimatter asymmetry.
Q & A
What is the ultimate goal in the field of particle physics?
-The ultimate goal in particle physics is to describe all the particles and forces that make up our universe.
What are the three big mysteries about our universe mentioned in the script?
-The three big mysteries are the accelerating expansion of the universe due to dark energy, the existence of dark matter, and the matter-antimatter asymmetry.
What is dark energy and why is it significant?
-Dark energy is an unknown force causing the universe's expansion to accelerate. It is significant because it makes up about 74% of the energy content of our universe, and its nature is still a mystery.
What is dark matter and how do we know it exists?
-Dark matter is a form of matter that does not interact with light or other electromagnetic radiation, making it invisible. Its existence is inferred from astrophysical observations, such as gravitational effects on visible matter.
What percentage of the universe's energy content is made up of dark matter?
-Dark matter makes up approximately 21% of the universe's energy content.
Why is the matter-antimatter asymmetry a problem in understanding the universe?
-The matter-antimatter asymmetry is a problem because, according to our current theories, matter and antimatter should have been created in equal amounts during the Big Bang, yet we observe a universe predominantly made of normal matter.
What is the standard model of particle physics?
-The standard model of particle physics is a theory that describes how all known particles and forces interact to form the structures of matter we observe.
How many fundamental particles are there in the standard model?
-There are 17 fundamental particles in the standard model.
What is the muon and why is it significant in particle physics?
-The muon is a subatomic particle similar to an electron but about 200 times heavier. It is significant because it can be used to search for new particles and forces that could explain the universe's mysteries.
What is the muon g-2 experiment and what does it aim to measure?
-The muon g-2 experiment, conducted at Fermilab, aims to measure the precession rate (wobbling) of muons in a magnetic field. Any deviation from the standard model's predictions could indicate the presence of new particles or forces.
What was the significance of the muon g-2 experiment's first result in April 2021?
-The first result from the muon g-2 experiment suggested that muons wobble faster than predicted by the standard model, indicating the possible influence of new particles or forces, although it has not yet reached the threshold for a definitive discovery.
What is the statistical significance threshold for claiming a discovery in particle physics?
-In particle physics, a discovery is claimed when the chance that the result is a fluke is less than one in 3.5 million.
Outlines
🌌 Mysteries of the Universe in Particle Physics
The speaker introduces three major mysteries in our understanding of the universe within the field of particle physics. The first mystery is the accelerating expansion of the universe, attributed to an unknown force called dark energy, which is estimated to constitute approximately 74% of the universe's energy content. The second mystery is dark matter, which is suggested to make up about 21% of the universe's energy content and is hypothesized to exist due to gravitational effects observed in galaxy clusters, despite not being directly observed. The third mystery pertains to the asymmetry between matter and antimatter, as theories predict equal amounts of both should have been created during the Big Bang, yet only matter is observed in the universe. The speaker emphasizes that solving these mysteries could involve the discovery of new particles or forces.
🔬 The Standard Model and the Muon's Role
The standard model of particle physics is presented as a comprehensive theory describing the known particles and forces in the universe, represented by 17 fundamental particles. This model has been instrumental in technological advancements such as solar power and nuclear fusion. However, it fails to account for the mysteries of dark energy, dark matter, and the matter-antimatter asymmetry. The speaker then introduces the muon, a heavier cousin of the electron, as a crucial tool in the search for new physics. Muons interact with all particles in the universe, and by measuring their precession (wobbling) rate in a magnetic field, physicists can detect deviations from the standard model, potentially revealing new particles or forces.
📊 Muon G-2 Experiment: A Potential Breakthrough
The speaker discusses the muon g-2 experiment at Fermilab, which measures the precession rate of muons in a magnetic field. The experiment's first results, released in April 2021, indicate a significant discrepancy between the observed precession rate and the prediction from the standard model. This suggests the presence of new particles or forces not accounted for in the current theory. The experimental results have a high statistical significance, with only a one in forty thousand chance of being a fluke. However, physicists require an even higher level of certainty, setting the threshold for a discovery at one in 3.5 million. While the experiment has not yet reached this threshold, the results are promising and further analysis will be conducted in the coming years. The implications of these findings could be profound, potentially shedding light on the fundamental mysteries of the universe.
Mindmap
Keywords
💡Universe
💡Dark Energy
💡Dark Matter
💡Big Bang
💡Standard Model of Particle Physics
💡Muon
💡Antimatter
💡Cosmic Rays
💡Fermilab Muon g-2 Experiment
💡Matter-Antimatter Asymmetry
Highlights
The ultimate goal in particle physics is to describe all particles and forces in the universe.
Despite progress, there are still big mysteries about the universe's composition and origin.
The universe is expanding, and its expansion is accelerating, a phenomenon attributed to dark energy.
Dark energy is unknown and makes up about 74% of the universe's energy content.
85% of the universe's matter is dark matter, detected indirectly through gravitational effects.
Dark matter is not directly observed on Earth but is inferred from astrophysical observations.
The matter-antimatter asymmetry is a puzzle, as the universe should contain equal amounts of both.
The Big Bang should have created matter and antimatter in equal amounts, but only matter is observed.
The standard model of particle physics describes known particles and forces but cannot explain dark energy, dark matter, or the matter-antimatter asymmetry.
The muon, a heavy cousin of the electron, is used to search for new particles and forces.
Muons wobble in a magnetic field, and their rate of wobbling can indicate interactions with unknown particles or forces.
The muon g-2 experiment at Fermilab measures the wobbling of muons to search for new physics.
The muon g-2 experiment's results suggest muons wobble faster than predicted by the standard model.
The discrepancy in muon wobbling speed could indicate new particles or forces not in the standard model.
The chance that the muon g-2 experiment's result is a fluke is statistically very low (1 in 40,000).
The experiment has not yet reached the discovery threshold of 1 in 3.5 million for claiming a new particle or force.
The muon g-2 experiment will continue to release results in the coming years, testing our understanding of the universe.
Particle physics experiments have historically led to advancements in technology and human civilization.
Transcripts
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