Three Colorado State University researchers hope 70,000 electronic and plastic precision parts will help unravel one of the most compelling mysteries surrounding the birth of the universe.
The parts–now in production at Colorado State and at several regional businesses–are part of a major international research effort to replicate the conditions present when the universe was less than a millionth of a second old.
The inch-long precision pieces, produced by physics professors Robert Wilson, Walter Toki and John Harton, will measure the distance and movement of certain particles of matter and anti-matter as they collide with each other. The collisions produce a very concentrated amount of pure energy, which in turn creates different types of matter and anti-matter. The project, housed at Stanford University, was designated a top scientific priority by President Bill Clinton.
Researchers hope this experiment, known as BaBar, explains why the universe is presently known to be composed primarily of matter, when matter and anti-matter were supposedly present in equal quantities at the moment of the Big Bang between 10 billion and 20 billion years ago.
This question has plagued scientists for years because it contradicts the fundamental laws that govern the way particles behave over time.
Wilson explained that after the Big Bang, particles and anti-particles should have interacted and annihilated each other as the universe cooled, leaving nothing but radiation. Instead, this very small violation of particle behavior is believed to be the reason more matter than anti-matter developed as the universe aged, leading to everything we see today.
"This is a hot area of high-energy physics, a frontier of the unknown," Wilson said. "It is daunting to think our experiments are probing the birth of the universe so closely." The project’s name, BaBar, refers to the B/B-bar system of particles, or mesons, that seem occasionally to violate the seemingly inviolable laws of particle behavior. Mesons are subatomic particles made up of pairs of quarks–thought to be the elementary particles of normal matter–and their anti-matter counterparts known as anti-quarks. Mesons play a role as the "glue" that keeps atomic nuclei from flying apart.
Most particles and anti-particles decay at similar rates. However, particles in the B/B-bar system occasionally decay at different rates over time, resulting in anti-particles that are slightly different.
"Should this violation be observed in the decay rates of these particular particles, there is reason to hope for a breakthrough in understanding how the universe was created," Wilson said.
"If there is such a violation, as we think there is, we must then ask ourselves if our current Standard Model outlining the behavior of particles correctly describes the effect–or is there something missing from this theory?" The parts produced by the Colorado State team will be installed in an experimental detector used to precisely measure the decay rates of these particles. The detector then will become part of a 1.5-mile circular collider under construction at Stanford.
The collisions produce pairs of B-mesons that decay quickly into long-lived particles that can be seen by the detector. High voltage wires precisely held by Colorado State’s components inside the detector will collect the electrical signals these particles leave behind, while other apparatus will record individual flashes of light with intensities less than 1 trillionth that of sunlight.
"We hope to be the scientists who have the first glimpse of these rare particle decays, which may explain in part the birth of the universe and how matter and anti-matter evolved," Toki said.
BaBar scientists–including those from Colorado State– already are simulating the experiment to prepare for the onslaught of data produced by the collisions, Toki said.
The physicists, with the aid of project engineer David Warner and a team including research assistants, graduate students and undergraduates at Colorado State, spent three years designing the parts. Some electronic components were designed in partnership with a group of scientists in France and tested in a particle beam in operation in Switzerland, Wilson said.
Colorado State’s portion of the research operates on a $250,000 annual grant from the U.S. Department of Energy and an additional $350,000 from the agency over the last two years to fund design work, produce equipment necessary to test the parts, and assemble the components.
The BaBar experiment represents one of the largest international undertakings in science history, including more than 530 physicists and engineers from 10 countries. Wilson is chairman of the governing council for the $85 million project, scheduled to begin experiments in 1999.
A consortium of Japanese universities, laboratories and private industry is building a similar particle collider that also is scheduled to begin experiments in 1999, which gives the BaBar project a special urgency for the scientists involved.
"It’s become a race against time," Wilson said. "Only recently was the computer technology developed to make this kind of an experiment possible. Now, the rush is on to find out if our theories about the birth of the universe are correct."