Particles not particularly useful

Jefferson Lab physicists find a 'strange quark' does less than earlier research indicated.

Nuclear physicists learned during recent testing at Jefferson Lab in Newport News that a puzzling subatomic particle contributes little to the electric and magnetic fields that hold atoms together.

The subatomic particles are strange quarks, which quickly appear and disappear inside of protons. Protons are an integral part of atoms - the basic units of matter.

"Whether it totally changes how we look at the proton is not clear," said Kent Paschke, a physicist involved in the research. "But it has changed the footing."

About one year ago, Jefferson Lab researchers announced that strange quarks might contribute to the proton's electric and magnetic fields. Scientists did not know how much strange quarks influenced those fields, but research indicated that they could account for as much as 10 percent of the magnetic field.

That meant researchers might have found a key ingredient in the recipe that creates magnetism.

But recent tests - the most precise ever - showed that strange quarks contribute to less than 1 percent of the electric field and no more than 5 percent of the magnetic field.