Introducing the Higgs Boson

“As a layman, I would now say, I think we have it!”

Rolf Heuer, Director General of CERN research lab in Geneva, Switzerland, was exuberant last week as researchers from the Large Hadron Collider there announced the discovery of a new fundamental particle. Since then, the Higgs boson and its 83-year-old Scottish namesake Peter Higgs have been catapulted upward into international fame. The discovery made the cover of last week’s Economist, has been re-packaged as a spoof reveal by the late Steve Jobs and has been explained as an animated comic. The Bay Area has a big community of physicists involved with the project, and the Physics Department at UC Berkeley has scheduled a special seminar on the topic this coming Friday.

But what is this new particle all about, and what’s a boson, anyway?

Any particle of matter can be classified into one of two categories depending on how it behaves in the presence of other particles like it. Fermions, which are one of these particle types, prefer to keep a healthy distance between each other. The fermionic nature of electrons has a huge influence on their spatial arrangement in matter. It explains why magnets are magnetic, why gold is a conductor but wood is not, and more fundamentally, why carbon, oxygen, and all the other elements have the distinctive properties that facilitate life and chemistry as we know it here on Earth.

In contrast to fermions, particles that are bosons love to sit on top of each other, and there is no limit to the number of bosons that can occupy a point in space at a given time. Photons (the fundamental particles of light) are bosons, for example, and you can light up an empty room as brightly as you want without running out of space.

The idea behind the Higgs boson was born in 1964 when three independent groups of scientists, including Peter Higgs, were playing with new theories of bosons. Theories until this point predicted that all of the elementary bosons ought to be massless. (This is true of the photon, but eventually turned out to be quite wrong for the W and Z bosons, which are responsible for radioactivity.) Higgs and his colleagues realized that the massless boson rule could be circumvented if they postulated that the Universe was enveloped in a theoretical construct called a field. An immediate consequence was that all of the known elementary particles—bosons and fermions alike—get their mass through interactions with this field. Given enough energy packed into a sufficiently small space, Higgs and his colleagues also predicted that it should be possible to coerce the field into spitting out a brand new elementary particle. It was a beautiful piece of mathematics, but in physics theories ultimately live or die by whether or not their predictions are born out in nature, and so began the 48-year hunt to find the elusive “God particle.”

With the latest announcement, is it finally safe to say that Higgs was right? CERN researchers have been cagey in their answers. Director General Heuer was quick to point out that they have definitely discovered a new particle (with odds better than a million to one), and that they know it is a boson, which is what Higgs and colleagues predicted. Still, it might not be quite what the theorists had in mind, and many checks are still being performed. Depending on your favorite theory, a single Higgs boson may not even suffice, and this could simply be one of many. In the end, confirmation of the Higgs won’t be the final word in particle physics. The theory of the new particle has almost nothing to say about other deep questions involving gravity or string theory. Alas, in science it often seems to be turtles all the way down.

More information on the Higgs can be learned this Friday at noon at UC Berkeley’s Valley Life Science Building (Chan Shun Auditorium), where the Physics Department will be holding a panel discussion with some of Berkeley’s professors, postdocs, and graduate students involved with the new discovery at CERN.

The Higgs Boson Explained

Panel Discussion
July 13 | 12-1 p.m. | Valley Life Sciences' Chan Shun Auditorium

Sponsor: Department of Physics

On Friday, July 13 at noon, join faculty and other members of the Physics
Department who will help the campus community understand the significance of
discovering the Higgs Boson, the particle that was predicted by Peter Higgs almost
50 years ago. Mark Richards, Executive Dean of the College of Letters & Sciences,
will host this discussion for the Berkeley community.

Event Contact: 510-642-7166