SLAC physicists react to Higgs boson announcement

The Higgs Boson particle, recently discovered in Geneva, is a groundbreaking find for the physics community. (OLLIE KHAKWANI/ The Stanford Daily)

Although the July 3 announcement regarding the discovery of the Higgs boson particle was made in Geneva, Switzerland, physicists at the SLAC National Accelerator Laboratory in Menlo Park were anything but distanced from the discovery.

Some Stanford researchers were there in Geneva. Ten Stanford-affiliated physicists were on location working for CERN at the European Laboratory for Particle Physics, some were in attendance at the International Conference of High Energy Physics in Melbourne, Australia, and some 25 theorists and six experimentalists waited until midnight to watch the announcement from SLAC itself.

The announcement revealed the findings of two independent research projects based at the Large Hadron Collider in Geneva — Compact Muon Solenoid (CMS) and ATLAS — which confirmed the existence of a particle that fit the profile constructed for the Higgs boson after years of speculation. Several SLAC physicists played a role in the ATLAS project.

“We saw the… reconstructed mass from the two experiments was roughly the same, 125 to 126 gigaelectron volts,” said SLAC experimental physicist Tim Barklow. “They both saw roughly the same signal and the same decay modes and roughly the same mass. And they both achieved that independently, so it was just absolute confirmation that a new particle had been seen.”

The important discovery of the particle resulted in an outpouring of praise and awe from scientists across the globe. The Higgs boson would explain the origin of mass through the establishment of a Higgs field, a ubiquitous quantum field responsibly for giving elementary particles their mass.

“What’s important is this thing called the Higgs field… and that’s what makes things have mass, that’s what makes things even exist,” said Andy Freeberg, director of media relations for SLAC. “So finding this Higgs boson, this particle, is sort of evidence for the fact that the Higgs field exists.”

Freeberg compares the Higgs field to a magnetic field. While in a magnetic field, objects are acted upon based on their mass, and a Higgs field would in and of itself determine this mass. The mass would be decided based on the extent to which the Higgs field interacts with different types of particles.

“The Higgs boson confirms what has been a crucial part of our understanding of subatomic particles for several decades,” Barklow said. “[It] has been theorized to give mass to all the fundamental particles in nature. And… the particle associated with this Higgs field has now been discovered after decades of searching.”

On top of the 40-odd SLAC physicists who played a direct role in the ATLAS project, research conducted at SLAC in the 1990s also paved the way for the discovery of the particle. Although SLAC’s particle collider is no longer in use, it facilitated research on the Z boson, another elementary particle. The understanding of the Z boson “helped determined where to look for the Higgs boson,” according to Freeburg.

Despite this landmark discovery in physics, however, both Barklow and Freeberg say that there is still much more ground to cover. The complexities of the Higgs boson and Higgs field still need to be mapped out. Their hope is that pinning down these specifics will allow the world of physics to apply this knowledge to other pressing questions, such as the existence of supersymmetry.

“This really key model, the standard model of physics, works,” Freeberg said, “and all of the major pieces are potentially now in place.”