The Particle at the End of the Universe: How the Hunt for the Higgs Boson Leads Us to the Edge of a New World by Sean Carroll Read Free Book Online Page A

a medium through which other particles move, affecting their properties along the way.

One major difference between the Higgs field and other fields is that the resting value of the Higgs is away from zero. All fields undergo tiny vibrations due to the intrinsic uncertainties of quantum mechanics. A larger vibration appears to us as a particle, in this case the Higgs boson.
    As we travel through space, we’re surrounded by the Higgs field and moving within it. Like the proverbial fish in water, we don’t usually notice it, but that field is what brings all the weirdness to the Standard Model.
    Executive summary
    There is a great deal of profound and challenging physics associated with the idea of the Higgs boson. But for right now let’s just give the overall summary of how the Higgs field works and why it’s important. Without further ado:
The world is made of fields —substances spread through all of space that we notice through their vibrations, which appear to us as particles. The electric field and the gravitational field might seem familiar, but according to quantum field theory even particles like electrons and quarks are really vibrations in certain kinds of fields.
The Higgs boson is a vibration in the Higgs field, just as a photon of light is a vibration in the electromagnetic field.
The four famous forces of nature arise from symmetries —changes we can make to a situation without changing anything important about what happens. (Yes, it makes no immediate sense that “a change that doesn’t make a difference” leads directly to “a force of nature” . . . but that was one of the startling insights of twentieth-century physics.)
Symmetries are sometimes hidden and therefore invisible to us. Physicists often say that hidden symmetries are “broken,” but they’re still there in the underlying laws of physics—they’re simply disguised in the immediately observable world.
The weak nuclear force, in particular, is based on a certain kind of symmetry. If that symmetry were unbroken, it would be impossible for elementary particles to have mass . They would all zip around at the speed of light.
But most elementary particles do have mass, and they don’t zip around at the speed of light. Therefore, the symmetry of the weak interactions must be broken.
When space is completely empty, most fields are turned off, set to zero. If a field is not zero in empty space, it can break a symmetry. In the case of the weak interactions, that’s the job of the Higgs field. Without it, the universe would be an utterly different place.
    Got all that? It’s a bit much to swallow, admittedly. It will make more sense when we complete our journey through the rest of the chapters. Trust me.
    The rest of the book will be a back-and-forth journey through the ideas behind the Higgs mechanism and the experimental quest to discover the boson. We’ll start with a quick overview of how the particles and forces of the Standard Model fit together, then explore the astonishing ways in which physicists use technology and gumption to discover new particles. After that it’s back to theory, as we think about fields and symmetries and how the Higgs can hide symmetries from our view. Finally we can show how the Higgs was discovered, how the news was spread, who will get the credit, and what it means for the future.
    It should be clear why Leon Lederman thought that the God Particle was an appropriate name for the Higgs boson. That boson is the hidden piece of equipment that explains the magic trick the universe is pulling on us, giving particles different masses and thereby making particle physics interesting. Without the Higgs, the intricate variety of the Standard Model would collapse to a featureless collection of pretty much identical particles, and all of the fermions would be essentially massless. There would be no atoms, no chemistry, no life as we know it. The Higgs boson, in a very real sense, is what brings the universe to