When the subatomic particles called neutrinos slam into atomic nuclei, the invisible missiles don't behave quite as expected, new findings indicate. While the discrepancy is small, researchers say its significance could be great. It may point to a previously unrecognized fundamental force of nature.
So far, physicists have identified only four such forces: gravity, electromagnetism, and the weak and strong forces. An analysis unveiled late last month at Fermi National Accelerator Laboratory (Fermilab) in Batavia, Ill., suggests that another type of weak force may have influenced neutrinos in an experiment conducted there in 1996 and 1997.