Physicists have performed the first run of a new experiment to detect axions — hypothetical particles that are predicted to be among the lightest particles in the universe. The team reports that in the first month of observations, the experiment detected no sign of axions within the mass range of 0.31 to 8.3 nanoelectronvolts. This means that axions within this mass range either don’t exist or they have an even smaller effect on electricity and magnetism than previously thought.