Clues to exotic particles found again

An experiment that found hints of what could be new subatomic particles last year has done it again.

A new analysis of data taken at Brookhaven National Laboratory in Upton, N.Y., shows that particles called muons wobble in a magnetic field faster than predicted by the prevailing theory of particle physics. Because the speed-up can’t be the handiwork of known particles, unknown ones may be responsible, says B. Lee Roberts of Boston University, a member of the experimental team.

Yet that’s just what he and his colleagues announced a year and a half ago (SN: 2/17/01, p. 102: Muon orbits may defy main physics theory), and then they had to back away. It turned out that they were relying on a calculation that was revealed last December to include a simple arithmetic error. After the calculations were corrected, the predicted and measured wobble rates weren’t so different.

Still, some disagreement with theory remained. Now, after analyzing many more muons, Lee and his colleagues say they have renewed confidence that the discrepancy suggests the presence of exotic new particles or some other unusual physics. The team reports its latest analysis in the Sept. 2 Physical Review Letters.

More Stories from Foogue on Physics