Fermilab’s Tevatron laid groundwork in search for ‘God particle’
By Jenette Sturges ~ firstname.lastname@example.org July 7, 2012 10:28PM
CMS scientist Oliver Gutsche (center right) can hardly contain his excitement, while he and fellow scientists Patty McBride (left) Dan Green and Rick Cavanaugh use a laptop to contact colleges in Switzerland and Australia after the announcement by scientists at CERN confirming that they along with Fermilab have found the Higgs boson, early Wednesday morning, July 4, 2012. | Steven Buyansky~Sun-Times Media
Updated: August 9, 2012 6:15AM
Nearly 14 billion years ago, our hot, dense universe would have fit many thousands of times on the head of a pin.
Then it exploded, with a bit of a bang, bringing along with it time, space and matter. The universe expanded, as it continues to do today, and it cooled enough for particles to form and to begin playing with one another.
Last week, physicists came a little bit closer to understanding how, a question that has eluded the science world for the past four and a half decades, ever since physicist Peter Higgs hypothesized a new particle that helped glue everything together.
“It’s responsible for the giving other particles mass,” said theorist Joe Lykken, “The Higgs energy field is like a sticky molasses that slows other particles from moving at the speed of light.”
The Higgs boson is the particle that helps transmit mass from the Higgs field to other particles. Without it, the entire universe would behave as photons do, whirring through space too fast to interact, too fast to build atoms, molecules, or planets.
“No clumping, no atoms, no molecules,” said Fermilab physicist Rob Roser. “Life itself would not exist.”
For years, physicists have been fighting the hyperbole around the hypothesized particle, but after last week’s announcements from the world’s foremost particle physics laboratories, the Higgs boson is nearing scientific fact.
“The Higgs boson is special,” said Lykken. “When (former Fermilab Director Leon Lederman) called it the ‘God particle’, he was making a joke, but it really gets at the center of why we’re here in the first place.”
Last Monday, Fermilab physicists announced they’d been through all their data on the hunt for the Higgs boson. They were achingly close.
“We tried,” said Roser. “We tried really, really hard. We didn’t quite get there, but I think we did the best we could do.”
The Hunt for Higgs
In many ways, the story of the Higgs boson is the story of Batavia’s Fermi National Accelerator Laboratory.
“Forty-five years ago, we postulated its existence,” said Dan Green, a physicist at Fermilab who is responsible for Fermilab and the CERN facility in Switzerland working together on CERN’s Large Hadron Collider. “Twenty years ago, we began building the technology that could find it.”
That technology was the Tevatron accelerator, the 3.9-mile double ring that smashed protons and anti-protons below the Batavia prairie for 24 years before it was shuttered last September.
To better understand the tiniest building blocks of the universe, physicists energized particles, collided them into each other, and watched the results on two separate particle detectors, dubbed CDF and DZero, looking for new sub-atomic particles — quarks and bosons — formed in the process.
But the Higgs boson is very rare and very heavy, which has made its discovery more elusive than other particles.
“One out of a trillion collisions creates a Higgs boson,” said Lykken. “This is not a needle in a haystack. It’s much worse.”
On average, the Tevatron has created just 200 likely Higgs boson particles a year, enough to study but falling short of the kind of statistically significant observations that can be called a discovery.
Even more challenging, when a Higgs boson is created, it decays rapidly and its signature looks much like that of other particles, giving scientists reams of data but only brief glances of their goal.
‘Torch has been passed’
The Tevatron is one of just two machines in the world with enough power to create Higgs boson particles.
The other is the Large Hadron Collider — or the LHC — at CERN, which collides just protons, but has more power and can create many more collisions in much less time. That means more data and more possibility for finding the elusive particle.
So at 2 a.m. Wednesday, Fermilab scientists gathered around, some in their pajamas, in anticipation of CERN’s most recent discovery — a Higgs-like particle.
CERN scientists have stopped short of definitively saying they’ve discovered the Higgs boson, but the particle they’ve found is consistent with predictions made by the Standard Model and with observations made at Fermilab. Scientists will continue running the LHC through February in an attempt to confirm their findings, but it could take years for scientists to determine whether the newly discovered particle is the Higgs boson or a Higgs look-alike.
Regardless, said Green, “The torch has been passed to the LHC.”
That may be true, but it does not mean that CERN can take all the credit. For one, physicists have collaborated on the search, sharing data, but also sharing workspace on the colliders. Fermilab physicists have been at the helm of the LHC since it started up two years ago, controlling the collider from the Remote Operations Center in Fermilab’s towering Wilson Hall.
What’s more, the Large Hadron Collider could not be possible were it not for the ground-breaking work of the Tevatron.
“The Tevatron was our seed in our code development, our algorithms, the way we can analyze the data,” said Green.
Physicists at Fermilab and CERN have been fielding a lot of questions in the past week from friends and neighbors. Not just “Have you found it?” Or “Does it have any practical application?” But also “Does this mean we can travel at light speed?”
As with all good answers in science, the discovery of the Higgs-like particle has simply led to more questions — though most physicists agree that we won’t be flipping our hyper-drives into light speed anytime soon, despite all the wild speculation.
But the question on the minds of each of the 700 or so scientists, engineers, administrators and support staff who go to work every morning on the prairie-grass-covered Fermilab campus is “What’s next?”
Months of data analysis in the search for the Higgs boson kept much of the laboratory busy since September 2011, when the Tevatron shut down, obsolete in the shadow of its more powerful European cousin.
Now, without its famous collider, Fermilab is far from shuttering, but it does need to re-tool.
Already the lab has been laying the groundwork for several new endeavors at the frontiers of physics — a high-intensity proton accelerator, equipment for the Dark Energy Survey that will help scientists understand the cosmic frontier, and a proposed International Linear Collider that would complement the work being done at CERN.
In the short-term, however, it will be the work remaining on the Higgs boson and the relationships in the physics community that will keep Fermilab going.
“The Large Hadron Collider has a 20-year future that is very bright. That means the future at Fermilab is also very bright,” said Green. “This is a triumph for physics. This is a triumph for Fermilab.”