Harry Cliff: Particle Physics and the Large Hadron Collider | Lex Fridman Podcast #92 | Summary and Q&A
The Large Hadron Collider is a massive particle accelerator that aims to understand the fundamental building blocks of the universe by studying particles such as the beauty quark, and it has the potential to answer some of the biggest questions in modern physics.
Questions & Answers
Q: How does the LHC work to study particles and their interactions?
The LHC works by accelerating particles, such as protons, to nearly the speed of light and then colliding them together. This collision creates high-energy conditions that allow scientists to study the properties and interactions of various particles. Detectors surrounding the collision point record the particles produced from the collision, which provides valuable information about the fundamental particles and their behavior.
Q: What is the significance of the discovery of the Higgs boson at the LHC?
The discovery of the Higgs boson at the LHC confirmed the existence of the Higgs field, which is responsible for giving mass to particles. This discovery completed the standard model of particle physics and provided a deeper understanding of why particles have the masses they do. It also opened up possibilities for further research and exploration of the fundamental laws of the universe.
Q: Are there any potential implications or applications of the research conducted at the LHC?
The research conducted at the LHC has the potential to answer some of the biggest questions in modern physics, such as the nature of dark matter, the possible existence of extra dimensions, and the unification of fundamental forces. It could lead to new innovations and technologies, as well as a deeper understanding of the fundamental laws that govern our universe.
Q: Are there any other theories or experiments being explored at the LHC besides the search for new particles?
Besides searching for new particles, the LHC is also being used to study the properties of known particles, such as the top quark and the Higgs boson, with high precision. Scientists are also conducting experiments to understand the behavior of matter and antimatter, as well as the possible formation of quark-gluon plasma, which is believed to have existed shortly after the Big Bang. The LHC is a versatile tool for various areas of research in particle physics.
In this conversation, Lex Friedman speaks with Harry Cliff, a particle physicist at the University of Cambridge working on the Large Hadron Collider beauty experiment. They discuss the Large Hadron Collider (LHC), the study of particle physics, and the search for new particles. They also touch on the concept of fields, the discovery of quarks, and the role of mass in the standard model of physics.
Questions & Answers
Q: What is the Large Hadron Collider (LHC) and how does it work?
The LHC is a 27-kilometer circumference particle accelerator buried 100 meters underground in Switzerland. It is used to understand the fundamental building blocks of the universe, similar to a gigantic microscope. It accelerates particles to nearly the speed of light and smashes them together to study the resulting particles and their interactions.
Q: What are quantum fields and how do they differ from particles?
Quantum fields are invisible, fluid-like objects that exist everywhere in space. They are the real building blocks of the universe, unlike particles which are not fundamental. Particles are actually ripples or vibrations in these fields. Fields, like the magnetic field, exist everywhere and fill the whole universe.
Q: Why is the study of vacuum important in particle physics?
In particle physics, the term "vacuum" refers to the study of the structure of empty space. It is important because particles are not the fundamental ingredients of the universe. The real building blocks are the quantum fields. Understanding the vacuum allows us to gain insight into the nature of particles and their interactions.
Q: Are you comfortable with the idea that the fundamental nature of reality is fields rather than particles?
Yes, the idea that particles are not really fundamental and are instead vibrations in fields is appealing and magical. It challenges the conventional view of atoms and opens up possibilities for new ways of understanding the universe.
Q: How does the LHC create disturbances in the Higgs field?
The LHC smashes protons into each other at high energies, which creates disturbances in the Higgs field. These disturbances are known as Higgs bosons. The detection of the Higgs boson is proof of the existence of the Higgs field. The Higgs field is believed to be responsible for giving particles mass.
Q: Why does the size of the LHC matter for particle acceleration?
The size of the LHC is important because it allows particles to be accelerated over and over again. The larger the machine, the more times particles can be accelerated and collide with each other. Smaller machines would require stronger magnets to bend the particles, which may not be feasible at the time.
Q: How do the magnetic fields in the LHC help accelerate particles?
The LHC uses magnets to steer and accelerate particles. As particles pass through metal boxes with alternating electric fields, they experience attractive and repulsive forces, causing them to gain speed. These magnetic fields must be synchronized with the particles' movement to achieve proper acceleration.
Q: What is the history of the standard model of particle physics?
The standard model of particle physics describes the fundamental particles and forces of the universe. It began with the discovery of electrons and the nucleus of atoms in the late 19th century. In the 20th century, experiments with cosmic rays and particle accelerators led to the discovery of a zoo of particles. Theorists proposed symmetries and quarks as the underlying structures. The standard model also includes the electromagnetic force, strong force, and weak force.
Q: How do investigators know that quarks are real if they have not been directly observed?
Quarks were inferred from scattering experiments where electrons were fired at protons. The electrons would bounce off hard objects inside the proton, which were determined to be quarks. Additionally, the quark model successfully predicts the existence of new particles and their interactions in experiments.
Q: Why are some particles massless while others have mass?
The Higgs field is introduced in the standard model to explain the origin of mass in particles. Particles like electrons interact with the Higgs field, causing them to acquire mass. The photon and gluons, which transmit the electromagnetic and strong forces, are massless particles. If the Higgs field were turned off, all particles in the standard model would be massless.
Particle physicists use accelerators like the LHC to study the fundamental building blocks of the universe. These building blocks are not particles, but invisible fields that are present everywhere. Particles are actually vibrations in these fields. The discovery of quarks and the introduction of the Higgs field in the standard model have provided insights into the nature of matter and the origin of mass. The study of particles and fields at the LHC continues to push the boundaries of our understanding of the universe.
Summary & Key Takeaways
The Large Hadron Collider (LHC) is a 27 kilometer circumference particle accelerator located in Switzerland that aims to understand the basic building blocks of the universe.
The LHC works by colliding particles together at high energies in order to study the properties and interactions of these particles.
The discovery of the Higgs boson at the LHC was a major breakthrough, confirming the existence of the Higgs field, which gives mass to particles, and completing the standard model of particle physics.