July 9, 2012
Duke's deep bench scores on the Higgs boson search
Physicists and their students play a critical role in new particle discovery.
By Ashley Yeager
After the flurry of announcements on July 4 that something strikingly similar to the Higgs boson had finally been found, it became much more clear just how deeply involved Duke physicists are in hunting for the elusive particle.
It turns out that 11 of Duke's 56 physicists, not including emeriti professors, are involved in the search either at the Large Hadron Collider (LHC) near Geneva, Fermilab or at both facilities. The department also supports five graduate students and 10 undergraduates who are beginning their careers in physics with one of the greatest hunts in science history.
For one of the scientists involved, assistant professor Ayana Arce, the announcement of the discovery was "thrilling." But she said she really wanted to "stand up and cheer" for the technical slides presented at the seminar.
These slides, she explained, "painted a clear picture of how our work in the Duke ATLAS group, which spreads out over different areas of LHC physics, converged to support this discovery." The technical details also presented the detector's "near-flawless performance" and "all the hard-earned improvements" in efficiency and in predictions of what the signal of the collisions should look like, she said.
Duke physics professor Seog Oh has been involved with the LHC-Higgs search since 1995, and led a team to design and construct one of the critical ATLAS detector components called the TRT, the Transition Radiation Tracker. It traces the particles left over after the protons slam into each other in the accelerator, and it then identifies electrons.
"This work was much more than just a job or a responsibility," Oh said. "I wanted to build something with a beauty that I could really be proud of, as I appreciate and envy well-designed and well-constructed gadgets and machines."
These are the undergrad students working on LHC-based projects. Credit: CERN/Duke.
Oh is also the Duke team leader of the ATLAS experiment and over the past decade has watched as his university collaborators have taken on the difficult task of calibrating and understanding the TRT detector.
"As we expected, it played a crucial role in discovering the new particle, which is likely the Higgs boson. Although there was great buzz in the ATLAS collaboration weeks prior to the formal announcement, the announcement itself was a really gratifying experience because I was a true partner of such a significant discovery," Oh said. "It was many small steps over the years that finally led to one giant step."
Both Oh and Arce, like many of the other physicists, realize that the Duke team's work is not done. The ATLAS team needs to determine whether it has found the Higgs boson predicted by the standard model that explains nature, or if it has instead found one of its cousins predicted to exist by a more complex model of the universe called SUSY.
Oh explained that the next step is to search for what lies beyond the standard model, which is incomplete, since it can't explain gravity or dark matter. "Depending on what Mother Nature had in mind when the universe was created, there could be many additional discoveries, or none whatsoever," he said.
"This is one area where many in the Duke high energy physics group, including myself, are looking for particles which can shed light beyond the standard model. Any discoveries beyond the standard model will have far-reaching consequences, even beyond that of the discovery of the Higgs boson," he said.
The team will be hunting for these particles using both the ATLAS experiment at LHC and a new experiment called Mu2e at Fermilab. At the US-based facility, the team will be searching for the "direct conversion of a muon to an electron, which is sensitive to the new physics and much more sensitive than the ATLAS experiment can ever be," Oh said.
"This new particle opens up a lot of concrete questions that we have to answer, if it is going to lead us to a clearer picture of how the universe works," Arce said, adding that it's exactly the kind of challenge that she likes to take on.