Jefferson Lab in the News
Like teen-age girls, quarks travel in packs, wiggling constantly, kept close together by a force stronger than peer pressure or even gossip.
Quarks in Cosmos Excite Physicists
Quarks, those fundamental particles that tantalize physicists, might truly be stellar.
Recently, astrophysicists announced that evidence suggesting that two collapsed, dense stars, thought to be composed of neutrons, might instead be made of quarks freed from the usual strong force that restrains their behavior.
The research is the latest on the "spectacular interaction" between the expanding cosmos and its tiniest constituents, said physicist Hans C. von Baeyer of the College of William and Mary.
"You'd think [particle physics and quarks] would have little to do with the cosmos," he said. But, "all these laws of the laboratory have to apply to the entire universe."
While many scientists view dubiously the findings from NASA's Chandra X-ray Observatory, "free" quarks have not been seen before outside the lab. Physicists have pursued them since the 1960s, and their elusiveness gave the hunt "a residual kind of romance," von Baeyer said.
"If you found such a star, smaller than a neutron star, that would be a biggie," said physicist Mark Sher of William and Mary, whose research areas include theoretical particle physics and cosmology.
If the controversial research holds up, "the theorists will have to sit down and think about the implications," said Will Brooks of the Thomas Jefferson National Accelerator Facility in Newport News. "It's already strange to think of a star as neutrons."
In ordinary matter, like this newspaper, groups of quarks make up the larger, familiar particles of our everyday lives, protons and neutrons. Like teen-age girls, quarks travel in packs, wiggling constantly, kept close together by a force stronger than peer pressure or even gossip. They have different personalities, or "flavors" - sometimes they're up, sometimes down, sometimes they're charming. They wear bizarre tops and bottoms, and sometimes they're flat-out strange.
In some dying stars bigger than our own sun, gravity squeezes the stellar material, squishing the electrons and protons to form neutrons. Astrophysicists think that in some bigger stars, those neutrons might break down into quarks.
Until now, free quarks have been observed only indirectly and fleetingly, in the wreckage of atoms smashed at particle labs like the Jefferson lab, where scientists focus on the structure of matter and how quarks relate.
The new work suggests that in the pressure cauldron of a star, quarks can end up packed together so tightly that they coalesce into a soup, Brooks said. Piled on top of each other, the triplets or doublets of quarks dissolve, freeing individual quarks - just as all quarks were in the immediate aftermath of the Big Bang.
To understand the earliest moments of the universe will require the understanding of matter, scientists say.
It's this criss-crossing of the mind-bending minute with the almost unimaginably massive that should be the focus of both physical and astronomical research in the coming decades as scientists strive to answer the most profound questions about the universe, according to a new report from the National Academies of Science.
"Recent advances made by physicists in understanding matter, space, and time and by astronomers in understanding the universe as a whole have paved the way to answer the really big questions," said Michael Turner, who led the panel that wrote the report, "Connecting Quarks with the Cosmos."