A University of Illinois at Chicago physicist will receive more than a half-million dollars to study something she'll never, ever directly see. Her subject is a sub-atomic particle called the "top quark."
Theories of its existence have been proven correct. But questions remain about this short-lived, tiny bit of matter considered a fundamental building block of our universe.
Assistant professor of physics Cecilia Gerber won a five-year, $523,000 National Science Foundation Career grant to answer two lingering questions about the top quark: are these particles produced singly as well as in pairs, and is there another "generation" of quarks beyond the three already known?
Gerber will use the Tevatron collider at the Fermi National Accelerator Laboratory in Batavia, Ill., where protons and anti-protons are continuously accelerated in opposite directions along parallel tracks, crossing at points where they crash and divide into sub-atomic bits that include quarks. Experiments at Fermilab's Tevatron -- the world's highest-energy particle accelerator -- confirmed the existence of the top quark back in 1995.
"The 'standard model' of atomic particles and fields, formulated in the 1970s, seems to be more or less correct, but it's not telling us the whole story," said Gerber. "There could be more than three generations of quarks. Nothing in the standard model limits it to just three. Also, the standard model does not explain why there's a hierarchy in particle mass -- why one type of quark has to be heavier than another."
To answer these questions, Gerber needs to gather and analyze a mound of data from particles shattered in the Tevatron collider. She'll also need to build a replacement for a special instrument called a silicon vertex detector.
Gerber helped build the present detector when she was a research associate at Fermilab, prior to joining the UIC faculty. She's co-principal investigator in a $1.7-million National Science Foundation major instrumentation grant to build the new detector. Constant atomic bombardment is expected to wear out the existing detector within the next three years. Gerber says her work will require at least that many years' worth of data.
Top quarks appear for a split second after 250 million collisions in the Tevatron, hidden among lots of other sub-atomic bits that cloud up the picture. Gerber will use a dedicated computer to sort out the conflicting information gathered from data runs to find the signatures of top quarks she wants to study.
"We have to develop a lot of clever techniques in order to find this needle in the haystack," she said. "It's going to precisely test the standard model in a way that has never been done before."
While Gerber's work is not designed for any immediate practical application, she hastens to point out that the quest for pure discovery has a long history of opening the way for technological advancements.
Gerber noted that when quantum theory was developed in the early 20th century by Niels Bohr and Ernest Rutherford to explain how matter behaved, "they weren't thinking about whether it would lead to development of transistors or computers."
"We cannot afford not to try to understand more," she said. "Otherwise we would never advance beyond our current technology."
For more information about UIC, visit www.uic.edu
RSS