Purdue University News Service 1132 Engineering Administration Building West Lafayette, IN 47907-1132 Voice: 317-494-2096 FAX: 317-494-0401
NOTE TO JOURNALISTS: A high-resolution color graphic depicting an artist's conception of the new electron model is available. Ask for the photo called Koltick/Electron.
January 10, 1997
RESEARCH SHEDS LIGHT ON ELECTRON'S STRUCTURE
WEST LAFAYETTE, Ind. ã According to recent measurements by Purdue University physicists, an electron may not be a simple negative point charge, as scientists often describe it.
"Science and engineering students have learned for years that the electron has a constant electronic strength, but now we've seen that this may not be the case," says David Koltick, professor of physics at Purdue.
Koltick says his research shows that the electromagnetic force from the electron, or its electronic strength, may increase toward the particle's central core.
According to his data, surrounding the electron's core is a fuzzy "cloud" of virtual particles, which wink in an out of existence in pairs ã one particle in the pair is positively charged, the other negatively charged.
The pairs essentially cancel each other out so that they do not "add" any net electric charge to the electron, Koltick says, but the cloud plays a key role in how we perceive the electromagnetic force from the electron.
"The cloud of virtual particles acts like a screen or curtain that shields the true value of the central core," Koltick explains. "As we probe into the cloud, getting closer and closer to the core charge, we 'see' less of the shielding effect and more of the core. This means that the electromagnetic force from the electron as a whole is not constant, but rather gets stronger as we go through the cloud and get closer to the core.
"Ordinarily when we look at or study an electron it is from far away and we don't realize the core is being shielded. We are the first researchers to actually measure this effect."
Koltick's results appear in the Jan. 20 issue of the journal Physical Review Letters.
Koltick and his colleagues also determined that the strong nuclear force, which is the "glue" that holds together elementary particles such as protons, gets weaker closer to the core charge. Other researchers also have seen this effect in the strong force.
"Because the electromagnetic charge is in effect becoming stronger as we get closer and the strong force is getting weaker, there is a possibility that these two forces may at some energy be equal," Koltick says. "Many physicists have speculated that when and if this is determined, an entirely new and unique physics may be discovered."
To obtain their results, Koltick and his colleagues, Purdue physics Professor Edward Shibata and former doctoral students Barry Howell and Ilan Levine, collided very high-speed beams of particles at a facility at the Japanese Laboratory for High Energy Physics.
aas/koltick.electron/9701f13
Source: David Koltick, (317) 494-5557; home, (317) 447-7932; e-mail, [email protected]
Writer: Amanda Siegfried, (317) 494-4709; home, (317) 497- 1245; e-mail, [email protected]
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