Twice during the last month the discovery of the pentaquark has been named among the top science stories for 2003. Researchers working at the Department of Energy's Jefferson Lab, located in Newport News, Va., are among those to identify some of the most convincing evidence yet of the subatomic particle's existence.
Discover Magazine's January 2004 issue listed the discovery at #9 in its "100 Top Science Stories of 2003" tally. And the American Institute of Physics listed the discovery among its Top 3 Physics Stories for 2003 in its Dec. 2 edition of Bulletin of Physics News (issue #664).
The particle was found while analyzing data at the Spring-8 particle accelerator in Japan after being predicted by Dmitri Diakonov, a theorist at the Nordic Institute of Theoretical Physics in Copenhagen, Denmark. Physicists have been hunting for five-quark states for over 35 years. The pentaquark is made up of two up quarks, two down quarks and an anti-strange quark.
Jefferson Lab researcher Stepan Stepanyan reported "convincing evidence" of a subatomic particle with five quarks, at the May 19-24 Conference on the Intersections of Particle and Nuclear Physics in New York City. Stepanyan was representing a multi-national collaboration of researchers as he presented Jefferson Lab's research supporting existence of the pentaquark. The research was funded through DOE's Office of Science.
According to Jefferson Lab Experimental Hall B Leader Volker Burkert, the pentaquark discovery could have profound implications not only for baryon spectroscopy, but for hadronic physics in general-a major research focus at many nuclear physics laboratories around the world.
"In a sense, it is really a new kind of matter," says nuclear physicist Ken Hicks of Ohio University. "For all we know it could have played a role in the early universe, very close to the Big Bang."
Submitted: Wednesday, December 24, 2003 - 2:00pm